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Shaydakov ME, Diaz JA, Eklöf B, Lurie F. Venous valve hypoxia as a possible mechanism of deep vein thrombosis: a scoping review. INT ANGIOL 2024; 43:309-322. [PMID: 38864688 DOI: 10.23736/s0392-9590.24.05170-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2024]
Abstract
INTRODUCTION The pathogenesis of deep vein thrombosis (DVT) has been explained by an interplay between a changed blood composition, vein wall alteration, and blood flow abnormalities. A comprehensive investigation of these components of DVT pathogenesis has substantially promoted our understanding of thrombogenesis in the venous system. Meanwhile, the process of DVT initiation remains obscure. This systematic review aims to collect, analyze, and synthesize the published evidence to propose hypoxia as a possible trigger of DVT. EVIDENCE ACQUISITION An exhaustive literature search was conducted across multiple electronic databased including PubMed, EMBASE, Scopus, and Web of Science to identify studies pertinent to the research hypothesis. The search was aimed at exploring the connection between hypoxia, reoxygenation, and the initiation of deep vein thrombosis (DVT). The following key words were used: "deep vein thrombosis," "venous thrombosis," "venous thromboembolism," "hypoxia," "reoxygenation," "venous valve," and "venous endothelium." Reviews, case reports, editorials, and letters were excluded. EVIDENCE SYNTHESIS Based on the systematic search outcome, 156 original papers relevant to the issue were selected for detailed review. These studies encompassed a range of experimental and observational clinical research, focusing on various aspects of DVT, including the anatomical, physiological, and cellular bases of the disease. A number of studies suggested limitations in the traditional understanding of Virchow's triad as an acceptable explanation for DVT initiation. Emerging evidence points to more complex interactions and additional factors that may be critical in the early stages of thrombogenesis. The role of venous valves has been recognized but remains underappreciated, with several studies indicating that these sites may act as primary loci for thrombus formation. A collection of studies describes the effects of hypoxia on venous endothelial cells at the cellular and molecular levels. Hypoxia influences several pathways that regulate endothelial cell permeability, inflammatory response, and procoagulation activity, underpinning the endothelial dysfunction noted in DVT. CONCLUSIONS Hypoxia of the venous valve may serve as an independent hypothesis to outline the DVT triggering process. Further research projects in this field may discover new molecular pathways responsible for the disease and suggest new therapeutic targets.
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Affiliation(s)
- Maxim E Shaydakov
- Division of Vascular Surgery, University of Pittsburgh Medical Center, Pittsburg, PA, USA -
| | - Jose A Diaz
- Division of Surgical Research, Vanderbilt University Medical Center, Nashville, TN, USA
| | | | - Fedor Lurie
- Jobst Vascular Institute, ProMedica Health System, Toledo, OH, USA
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Kim KW, Lee C, Im G, Kang HJ, Jo MS, Jeon SJ, Kim JS, Lee SB, Kim MU, Choi YH, Kim HH. Optimal thrombin injection method for the treatment of femoral artery pseudoaneurysm. J Thromb Haemost 2024; 22:1389-1398. [PMID: 38278416 DOI: 10.1016/j.jtha.2023.12.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Revised: 12/06/2023] [Accepted: 12/27/2023] [Indexed: 01/28/2024]
Abstract
BACKGROUND Iatrogenic femoral artery pseudoaneurysm (IFP) incidence is increasing with increase in diagnostic and therapeutic angiography, and so, the less invasive percutaneous thrombin injection (PTI) is the most widely used treatment. Moreover, studies that minimize PTI complications and highlight therapeutic effects are lacking. OBJECTIVES This study performed in vitro thrombosis modeling of pseudoaneurysms and analyzed thrombosis within and thromboembolism outside the sac during thrombin injection. METHODS We evaluated PTI in terms of thrombin injection location (at the junction of the IFP sac and neck, the center, and the dome, located farthest from the neck of the sac), thrombin injection time (5 and 8 seconds), and blood flow rate (ranging from 210 mL/min to 300 mL/min). Porcine blood was used as the working fluid in this study. RESULTS Thrombin injection at the junction of the IFP sac and the pseudoaneurysm neck led to less thrombosis within the sac but substantial thrombi consistently outside the sac, whereas thrombin injected at the sac center mostly led to complete thrombosis within the sac, preventing further blood flow into the sac and reducing likelihood of thrombi outside the sac. A longer thrombin injection time enhanced the therapeutic effect and decreased the possibility of thromboembolism. Thromboembolism occurred more frequently at flow rates of >240 mL/min. CONCLUSION The thrombin injection site in a pseudoaneurysm significantly influences thrombogenesis within and thromboembolism outside the sac. Thus, slow and deliberate injection of thrombin into the center of the sac could potentially reduce complications and enhance treatment efficacy.
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Affiliation(s)
- Kyung-Wuk Kim
- Department of Mechanical Engineering, Soongsil University, Seoul, Republic of Korea
| | - Changje Lee
- Research Institute of Maritime Industry, Korea Maritime and Ocean University, Busan, Republic of Korea
| | - Gyeongtae Im
- Process Analysis Team, Mirae Energy & Environment, Hazardous Material & Health, and Safety & Security-code Research Institute, Iljik-ro, Gwangmyeong-si, Gyeonggi-do, Republic of Korea
| | - Hyo-Jeong Kang
- School of Mechanical Material Convergence Engineering, Gyeongsang National University, Jinju, Gyeongnam, Republic of Korea
| | - Mun-Seong Jo
- School of Mechanical Material Convergence Engineering, Gyeongsang National University, Jinju, Gyeongnam, Republic of Korea
| | - Sang-Jin Jeon
- School of Mechanical Material Convergence Engineering, Gyeongsang National University, Jinju, Gyeongnam, Republic of Korea
| | - Jeong-Sik Kim
- School of Mechanical Material Convergence Engineering, Gyeongsang National University, Jinju, Gyeongnam, Republic of Korea
| | - Seung Bae Lee
- Department of Urology, Sheikh Khalifa Specialty Hospital, United Arab Emirates
| | - Min Uk Kim
- Department of Radiology, Seoul National University College of Medicine, SMG-SNU Boramae Medical Center, Dongjak-gu, Seoul, Republic of Korea
| | - Young Ho Choi
- Department of Radiology, Seoul National University College of Medicine, SMG-SNU Boramae Medical Center, Dongjak-gu, Seoul, Republic of Korea.
| | - Hyoung-Ho Kim
- School of Mechanical Material Convergence Engineering, Gyeongsang National University, Jinju, Gyeongnam, Republic of Korea.
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Steins K, Goolsby C, Grönbäck AM, Charlton N, Anderson K, Dacuyan-Faucher N, Prytz E, Andersson Granberg T, Jonson CO. Recommendations for Placement of Bleeding Control Kits in Public Spaces-A Simulation Study. Disaster Med Public Health Prep 2023; 17:e527. [PMID: 37852924 DOI: 10.1017/dmp.2023.190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2023]
Abstract
OBJECTIVE Bleeding control measures performed by members of the public can prevent trauma deaths. Equipping public spaces with bleeding control kits facilitates these actions. We modeled a mass casualty incident to investigate the effects of public bleeding control kit location strategies. METHODS We developed a computer simulation of a bomb exploding in a shopping mall. We used evidence and expert opinion to populate the model with parameters such as the number of casualties, the public's willingness to aid, and injury characteristics. Four alternative placement strategies of public bleeding control kits in the shopping mall were tested: co-located with automated external defibrillators (AEDs) separated by 90-second walking intervals, dispersed throughout the mall at 10 locations, located adjacent to 1 exit, located adjacent to 2 exits. RESULTS Placing bleeding control kits at 2 locations co-located with AEDs resulted in the most victims surviving (18.2), followed by 10 kits dispersed evenly throughout the mall (18.0). One or 2 kit locations placed at the mall's main exits resulted in the fewest surviving victims (15.9 and 16.1, respectively). CONCLUSIONS Co-locating bleeding control kits with AEDs at 90-second walking intervals results in the best casualty outcomes in a modeled mass casualty incident in a shopping mall.
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Affiliation(s)
- Krisjanis Steins
- Department of Science and Technology, Linköping University, Sweden
| | - Craig Goolsby
- Department of Emergency Medicine, Harbor-UCLA Medical Center, Torrance, CA, USA
- David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | | | - Nathan Charlton
- Department of Emergency Medicine, University of Virginia, Charlottesville, VA, USA
| | - Kevin Anderson
- F. Edward Hebert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Nicole Dacuyan-Faucher
- Department of Emergency Medicine, Harbor-UCLA Medical Center, Torrance, CA, USA
- The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Erik Prytz
- Department of Computer and Information Science, Linköping University, Sweden
- Center for Disaster Medicine and Traumatology, and Department of Biomedical and Clinical Sciences, Linköping University, Sweden
| | | | - Carl-Oscar Jonson
- Center for Disaster Medicine and Traumatology, and Department of Biomedical and Clinical Sciences, Linköping University, Sweden
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Wang SH, Shyu VBH, Chiu WK, Huang RW, Lai BR, Tsai CH. An Overview of Clinical Examinations in the Evaluation and Assessment of Arterial and Venous Insufficiency Wounds. Diagnostics (Basel) 2023; 13:2494. [PMID: 37568858 PMCID: PMC10417660 DOI: 10.3390/diagnostics13152494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Revised: 07/11/2023] [Accepted: 07/17/2023] [Indexed: 08/13/2023] Open
Abstract
Arterial and venous insufficiency are two major causes of chronic wounds with different etiology, pathophysiology, and clinical manifestations. With recent advancements in clinical examination, clinicians are able to obtain an accurate diagnosis of the underlying disease, which plays an important role in the treatment planning and management of patients. Arterial ulcers are mainly caused by peripheral artery diseases (PADs), which are traditionally examined by physical examination and non-invasive arterial Doppler studies. However, advanced imaging modalities, such as computed tomography angiography (CTA) and indocyanine green (ICG) angiography, have become important studies as part of a comprehensive diagnostic process. On the other hand, chronic wounds caused by venous insufficiency are mainly evaluated by duplex ultrasonography and venography. Several scoring systems, including Clinical-Etiology-Anatomy-Pathophysiology (CEAP) classification, the Venous Clinical Severity Score (VCSS), the Venous Disability Score, and the Venous Segmental Disease Score (VSDS) are useful in defining disease progression. In this review, we provide a comprehensive overlook of the most widely used and available clinical examinations for arterial and venous insufficiency wounds.
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Affiliation(s)
- Szu-Han Wang
- Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, Keelung Branch, Keelung 204, Taiwan; (S.-H.W.); (V.B.-H.S.); (B.-R.L.)
- Graduate Institute of Biomedical Informatics, Taipei Medical University, Taipei 110, Taiwan
| | - Victor Bong-Hang Shyu
- Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, Keelung Branch, Keelung 204, Taiwan; (S.-H.W.); (V.B.-H.S.); (B.-R.L.)
- College of Medicine, Chang Gung University, Taoyuan 333, Taiwan;
| | - Wen-Kuan Chiu
- Division of Plastic Surgery, Department of Surgery, Wan Fang Hospital, Taipei Medical University, Taipei 116, Taiwan;
- Department of Surgery, School of Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan
| | - Ren-Wen Huang
- College of Medicine, Chang Gung University, Taoyuan 333, Taiwan;
- Division of Trauma Plastic Surgery, Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, Taoyuan 333, Taiwan
| | - Bo-Ru Lai
- Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, Keelung Branch, Keelung 204, Taiwan; (S.-H.W.); (V.B.-H.S.); (B.-R.L.)
- College of Medicine, Chang Gung University, Taoyuan 333, Taiwan;
| | - Chia-Hsuan Tsai
- Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, Keelung Branch, Keelung 204, Taiwan; (S.-H.W.); (V.B.-H.S.); (B.-R.L.)
- College of Medicine, Chang Gung University, Taoyuan 333, Taiwan;
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Toro EF, Celant M, Zhang Q, Contarino C, Agarwal N, Linninger A, Müller LO. Cerebrospinal fluid dynamics coupled to the global circulation in holistic setting: Mathematical models, numerical methods and applications. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2022; 38:e3532. [PMID: 34569188 PMCID: PMC9285081 DOI: 10.1002/cnm.3532] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 09/13/2021] [Indexed: 06/13/2023]
Abstract
This paper presents a mathematical model of the global, arterio-venous circulation in the entire human body, coupled to a refined description of the cerebrospinal fluid (CSF) dynamics in the craniospinal cavity. The present model represents a substantially revised version of the original Müller-Toro mathematical model. It includes one-dimensional (1D), non-linear systems of partial differential equations for 323 major blood vessels and 85 zero-dimensional, differential-algebraic systems for the remaining components. Highlights include the myogenic mechanism of cerebral blood regulation; refined vasculature for the inner ear, the brainstem and the cerebellum; and viscoelastic, rather than purely elastic, models for all blood vessels, arterial and venous. The derived 1D parabolic systems of partial differential equations for all major vessels are approximated by hyperbolic systems with stiff source terms following a relaxation approach. A major novelty of this paper is the coupling of the circulation, as described, to a refined description of the CSF dynamics in the craniospinal cavity, following Linninger et al. The numerical solution methodology employed to approximate the hyperbolic non-linear systems of partial differential equations with stiff source terms is based on the Arbitrary DERivative Riemann problem finite volume framework, supplemented with a well-balanced formulation, and a local time stepping procedure. The full model is validated through comparison of computational results against published data and bespoke MRI measurements. Then we present two medical applications: (i) transverse sinus stenoses and their relation to Idiopathic Intracranial Hypertension; and (ii) extra-cranial venous strictures and their impact in the inner ear circulation, and its implications for Ménière's disease.
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Affiliation(s)
| | - Morena Celant
- Department of MathematicsUniversity of TrentoTrentoItaly
| | - Qinghui Zhang
- Laboratory of Applied Mathematics, DICAMUniversity of TrentoTrentoItaly
| | | | | | - Andreas Linninger
- Department of BioengineeringUniversity of Illinois at ChicagoChicagoIllinoisUSA
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Jones G, Parr J, Nithiarasu P, Pant S. A physiologically realistic virtual patient database for the study of arterial haemodynamics. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2021; 37:e3497. [PMID: 33973397 DOI: 10.1002/cnm.3497] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 04/30/2021] [Accepted: 04/30/2021] [Indexed: 06/12/2023]
Abstract
This study creates a physiologically realistic virtual patient database (VPD), representing the human arterial system, for the primary purpose of studying the effects of arterial disease on haemodynamics. A low dimensional representation of an anatomically detailed arterial network is outlined, and a physiologically realistic posterior distribution for its parameters constructed through the use of a Bayesian approach. This approach combines both physiological/geometrical constraints and the available measurements reported in the literature. A key contribution of this work is to present a framework for including all such available information for the creation of virtual patients (VPs). The Markov Chain Monte Carlo (MCMC) method is used to sample random VPs from this posterior distribution, and the pressure and flow-rate profiles associated with each VP computed through a physics based model of pulse wave propagation. This combination of the arterial network parameters (representing a virtual patient) and the haemodynamics waveforms of pressure and flow-rates at various locations (representing functional response and potential measurements that can be acquired in the virtual patient) makes up the VPD. While 75,000 VPs are sampled from the posterior distribution, 10,000 are discarded as the initial burn-in period of the MCMC sampler. A further 12,857 VPs are subsequently removed due to the presence of negative average flow-rate, reducing the VPD to 52,143. Due to undesirable behaviour observed in some VPs-asymmetric under- and over-damped pressure and flow-rate profiles in left and right sides of the arterial system-a filter is proposed to remove VPs showing such behaviour. Post application of the filter, the VPD has 28,868 subjects. It is shown that the methodology is appropriate by comparing the VPD statistics to those reported in literature across real populations. Generally, a good agreement between the two is found while respecting physiological/geometrical constraints.
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Affiliation(s)
- Gareth Jones
- College of Engineering, Swansea University, Swansea, UK
| | - Jim Parr
- Applied Technologies, McLaren Technology Centre, Woking, UK
| | | | - Sanjay Pant
- College of Engineering, Swansea University, Swansea, UK
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Differences in Femoral Artery Occlusion Pressure between Sexes and Dominant and Non-Dominant Legs. ACTA ACUST UNITED AC 2021; 57:medicina57090863. [PMID: 34577785 PMCID: PMC8471356 DOI: 10.3390/medicina57090863] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 08/21/2021] [Accepted: 08/21/2021] [Indexed: 11/17/2022]
Abstract
Background and Objectives: Blood flow restriction during low-load exercise stimulates similar muscle adaptations to those normally observed with higher loads. Differences in the arterial occlusion pressure (AOP) between limbs and between sexes are unclear. We compared the AOP of the superficial femoral artery in the dominant and non-dominant legs, and the relationship between blood flow and occlusion pressure in 35 (16 males, 19 females) young adults. Materials and Methods: Using ultrasound, we measured the AOP of the superficial femoral artery in both legs. Blood flow at occlusion pressures ranging from 0% to 100% of the AOP was measured in the dominant leg. Results: There was a significant difference in the AOP between males and females in the dominant (230 ± 41 vs. 191 ± 27 mmHg; p = 0.002) and non-dominant (209 ± 37 vs. 178 ± 21 mmHg; p = 0.004) legs, and between the dominant and non-dominant legs in males (230 ± 41 vs. 209 ± 37 mmHg; p = 0.009) but not females (191 ± 27 vs. 178 ± 21 mmHg; p = 0.053), respectively. Leg circumference was the most influential independent predictor of the AOP. There was a linear relationship between blood flow (expressed as a percentage of unoccluded blood flow) and occlusion pressure (expressed as a percentage of AOP). Conclusions: Arterial occlusion pressure is not always greater in the dominant leg or the larger leg. Practitioners should measure AOP in both limbs to determine if occlusion pressures used during exercise should be limb specific. Occlusion pressures used during blood flow restriction exercise should be chosen carefully.
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Limberg JK, Casey DP, Trinity JD, Nicholson WT, Wray DW, Tschakovsky ME, Green DJ, Hellsten Y, Fadel PJ, Joyner MJ, Padilla J. Assessment of resistance vessel function in human skeletal muscle: guidelines for experimental design, Doppler ultrasound, and pharmacology. Am J Physiol Heart Circ Physiol 2019; 318:H301-H325. [PMID: 31886718 DOI: 10.1152/ajpheart.00649.2019] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The introduction of duplex Doppler ultrasound almost half a century ago signified a revolutionary advance in the ability to assess limb blood flow in humans. It is now widely used to assess blood flow under a variety of experimental conditions to study skeletal muscle resistance vessel function. Despite its pervasive adoption, there is substantial variability between studies in relation to experimental protocols, procedures for data analysis, and interpretation of findings. This guideline results from a collegial discussion among physiologists and pharmacologists, with the goal of providing general as well as specific recommendations regarding the conduct of human studies involving Doppler ultrasound-based measures of resistance vessel function in skeletal muscle. Indeed, the focus is on methods used to assess resistance vessel function and not upstream conduit artery function (i.e., macrovasculature), which has been expertly reviewed elsewhere. In particular, we address topics related to experimental design, data collection, and signal processing as well as review common procedures used to assess resistance vessel function, including postocclusive reactive hyperemia, passive limb movement, acute single limb exercise, and pharmacological interventions.
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Affiliation(s)
- Jacqueline K Limberg
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri
| | - Darren P Casey
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, Iowa City, Iowa.,François M. Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, Iowa.,Fraternal Order of Eagles Diabetes Research, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Joel D Trinity
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | | | - D Walter Wray
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | - Michael E Tschakovsky
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Daniel J Green
- School of Human Sciences (Exercise and Sport Science), University of Western Australia, Perth, Western Australia, Australia
| | - Ylva Hellsten
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Paul J Fadel
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas
| | | | - Jaume Padilla
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri.,Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
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Doppler Flow Measurement of Lower Extremity Arteries Adjusted by Pulsatility Index. AJR Am J Roentgenol 2019; 214:10-17. [PMID: 31670583 DOI: 10.2214/ajr.19.21280] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE. The purposes of this study were to estimate the blood volume flow of the lower extremities by means of Doppler technique; to establish a quantitative relationship between volume flow and pulsatility index (PI) in both healthy subjects and patients with peripheral artery disease (PAD); and to derive arterial blood flow equations in the lower extremities for more accurate volume flow estimations. SUBJECTS AND METHODS. Sixty healthy subjects were recruited. Arterial diameter, peak systolic velocity, PI, time-averaged mean velocity, and volume flow of right lower extremity arteries were measured with duplex Doppler ultrasound. Linear regression analysis was used to evaluate the relationship between volume flow and the reciprocal of PI. This quantitative relationship was also used to assess flow changes in 10 patients with PAD before, after, or both before and after percutaneous angioplasty. RESULTS. Volume flow in the common femoral artery was 434.4 mL/min; superficial femoral artery, 172.5 mL/min; popliteal artery, 92.1 mL/min; dorsalis pedis artery, 11.8 mL/min; and common plantar artery, 12.0 mL/min. Linear relationships between the reciprocal of PI and volume flow were found and expressed as linear blood flow equations. For the patients with PAD, no statistical increase in measured flow in the downstream artery after percutaneous angioplasty was found (p = 0.1), although four arteries had decreased flow. After normalization of flow measurements with PI values, however, statistical increases were observed between percentage increment (p < 0.001) calculations. CONCLUSION. When real-time PI values are factored into blood volume flow calculations in the evaluation of lower extremity arteries, discrepancies in flow measurements can be resolved, resulting in more accurate and stable measurements of clinical and diagnostic significance.
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Gornati VC, Utsunomia K, de Lima TB, de Freitas Barão FT, Faccioli Lopes D, da Silva ES. Development of a Puncture Technique for Implanting Temporary Vascular Shunts in a Porcine Model. Ann Vasc Surg 2019; 60:455-462. [PMID: 31200035 DOI: 10.1016/j.avsg.2019.03.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 02/12/2019] [Accepted: 03/02/2019] [Indexed: 11/29/2022]
Abstract
BACKGROUND Temporary vascular shunts (TVSs) are an effective tool for rapidly restoring blood flow to a limb or organ that has experienced vascular injury and ischemia and for which revascularization is not an immediate option. Usually, through an opening in the skin, the TVS is positioned within the proximal and distal stumps of the injured vessel, restoring perfusion and stopping the ischemia. The aim of this study is to compare standard TVS technique and a developed puncture technique for implanting TVS and to evaluate the utility and feasibility of this protocol after arterial lesions, in pigs. METHODS Vascular injuries were inflicted in both hind limbs of 30 pigs, and vascular interventions were performed, using standard and puncture TVS. Because each pig was implanted with both types of TVSs, it was possible to simultaneously monitor, analyze, and compare parameters such as, the mean arterial pressure (MAP, in mm Hg), blood flow (mL/min), and insertion times, in the same animal. RESULTS It was observed that the MAP in the limbs recovered and approached systemic MAP, in 100% of the experiments, in both groups. Analysis of the blood flow data showed that this parameter was significantly reduced in the puncture TVS group (110.36 ± 9.99 mL/min vs. 153.20 ± 18.57 mL/min, P = 0.001). On the other hand, the insertion time for the standard TVS was significantly greater than that of the puncture shunt (15.32 ± 3.08 min vs. 10.37 ± 1.7 min, P = 0.001). Furthermore, it was found that the primary and secondary patency and complication rates were similar for both TVS types. CONCLUSION Thus, given the adequate MAP recovery and reduction in implantation time observed in this experimental and in an animal model study, the use of the puncture TVS technique is effective and feasible.
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Affiliation(s)
- Vitor Cervantes Gornati
- Division of Vascular and Endovascular Surgery, Universidade de São Paulo, São Paulo, SP, Brazil.
| | - Karen Utsunomia
- Division of Vascular and Endovascular Surgery, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Thaíssio Britto de Lima
- Division of Vascular and Endovascular Surgery, Universidade de São Paulo, São Paulo, SP, Brazil
| | | | - Daniel Faccioli Lopes
- Division of Vascular and Endovascular Surgery, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Erasmo Simão da Silva
- Division of Vascular and Endovascular Surgery, Universidade de São Paulo, São Paulo, SP, Brazil
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Natta L, Mastronardi VM, Guido F, Algieri L, Puce S, Pisano F, Rizzi F, Pulli R, Qualtieri A, De Vittorio M. Soft and flexible piezoelectric smart patch for vascular graft monitoring based on Aluminum Nitride thin film. Sci Rep 2019; 9:8392. [PMID: 31182738 PMCID: PMC6557862 DOI: 10.1038/s41598-019-44784-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 05/21/2019] [Indexed: 12/16/2022] Open
Abstract
Vascular grafts are artificial conduits properly designed to substitute a diseased blood vessel. However prosthetic fail can occur without premonitory symptoms. Continuous monitoring of the system can provide useful information not only to extend the graft's life but also to optimize the patient's therapy. In this respect, various techniques have been used, but all of them affect the mechanical properties of the artificial vessel. To overcome these drawbacks, an ultrathin and flexible smart patch based on piezoelectric Aluminum Nitride (AlN) integrated on the extraluminal surface of the prosthesis is presented. The sensor can be conformally wrapped around the external surface of the prosthesis. Its design, mechanical properties and dimensions are properly characterized and optimized in order to maximize performances and to avoid any interference with the graft structure during its activity. The sensorized graft is tested in vitro using a pulsatile recirculating flow system that mimics the physiological and pathological blood flow conditions. In this way, the ability of the device to measure real-time variations of the hemodynamics parameters has been tested. The obtained high sensitivity of 0.012 V Pa-1 m-2, joint to the inherent biocompatibility and non-toxicity of the used materials, demonstrates that the device can successfully monitor the prosthesis functioning under different conditions, opening new perspectives for real-time vascular graft surveillance.
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Affiliation(s)
- L Natta
- Center for Biomolecular Nanotechnologies, Istituto Italiano di Tecnologia, 73010, Arnesano, Le, Italy.
- Università del Salento, 73100, Lecce, Italy.
| | - V M Mastronardi
- Center for Biomolecular Nanotechnologies, Istituto Italiano di Tecnologia, 73010, Arnesano, Le, Italy
| | - F Guido
- Center for Biomolecular Nanotechnologies, Istituto Italiano di Tecnologia, 73010, Arnesano, Le, Italy
| | - L Algieri
- Center for Biomolecular Nanotechnologies, Istituto Italiano di Tecnologia, 73010, Arnesano, Le, Italy
- Università del Salento, 73100, Lecce, Italy
| | - S Puce
- Center for Biomolecular Nanotechnologies, Istituto Italiano di Tecnologia, 73010, Arnesano, Le, Italy
- Università del Salento, 73100, Lecce, Italy
| | - F Pisano
- Center for Biomolecular Nanotechnologies, Istituto Italiano di Tecnologia, 73010, Arnesano, Le, Italy
| | - F Rizzi
- Center for Biomolecular Nanotechnologies, Istituto Italiano di Tecnologia, 73010, Arnesano, Le, Italy
| | - R Pulli
- Università di Bari 'Aldo Moro', Department of vascular surgery, 70121, Bari, Italy
| | - A Qualtieri
- Center for Biomolecular Nanotechnologies, Istituto Italiano di Tecnologia, 73010, Arnesano, Le, Italy
| | - M De Vittorio
- Center for Biomolecular Nanotechnologies, Istituto Italiano di Tecnologia, 73010, Arnesano, Le, Italy
- Università del Salento, 73100, Lecce, Italy
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12
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Flecha I, Naylor JF, Schauer SG, Curtis RA, Cunningham CW. Combat lifesaver-trained, first-responder application of junctional tourniquets: a prospective, randomized, crossover trial. Mil Med Res 2018; 5:31. [PMID: 30208960 PMCID: PMC6136177 DOI: 10.1186/s40779-018-0178-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 09/06/2018] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Junctional hemorrhage surpassed extremity hemorrhage as the leading cause of preventable death after the resurgence of limb tourniquets during the recent conflicts in Afghanistan and Iraq. Junctional tourniquets (JTQs) were developed in response to this injury pattern. Published data for JTQ efficacy are limited and do not incorporate nonmedical, military first responders. We compared the time for effective placement and scores for device satisfaction between two different JTQs, stratified by combat lifesaver (CLS) and combat medics. METHODS We performed a prospective, randomized, crossover trial utilizing the SAM® Medical Junctional Tourniquet (SJT) and Junctional Emergency Treatment Tool (JETT™). Investigators simple randomized CLS and combat medics to SJT or JETT for their first JTQ application on mannequins with penetrating inguinal injuries. Then, participants immediately placed the other JTQ on another casualty with the same injury. The primary outcome measured was time of successful application. Success was defined as proper JTQ placement and a pressure reading of at least 180 mmHg. We compared outcomes between CLS and combat medics. Unsuccessful JTQ applications were excluded from the comparative analysis. RESULTS From June 2015 to August 2015, a total of 227 personnel (133 CLS and 94 combat medics) at Fort Hood, Texas, USA volunteered to participate in the study. Twenty-eight percent (38 of 133) of CLS and 40% (38 of 94) of combat medics placed both JTQs successfully, for a total of 152 applications (76 SJTs and 76 JETTs). We found a significant difference between applications of the JETT between the CLS and combat medics (92.0 ± 37.7 s versus 70.5 ± 20.5 s, P = 0.004). No other subgroup analyses, whether by device or user, demonstrated a significant difference in application time. Both groups preferred the SJT over the JETT. CLS disagreed with combat medics that the JETT could be easily applied by one person (median 3.0 [2.0, 4.0] versus median 4.0 [3.0, 5.0]; P = 0.006). CONCLUSION Overall, success rates for both the SJT and JETT were low. Improved training is needed to increase successful application of junctional tourniquets before widespread implementation. Combat lifesavers and combat medics prefer the SJT over the JETT.
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Affiliation(s)
- Ismael Flecha
- 21st Combat Support Hospital, Fort Hood, Killeen, 76544, TX, USA
| | - Jason F Naylor
- Madigan Army Medical Center, JBLM Fort Lewis, Lakewood, 98431, USA.
| | - Steven G Schauer
- San Antonio Military Medical Center, JBSA Fort Sam Houston, San Antonio, 78234, TX, USA.,US Army Institute of Surgical Research, JBSA Fort Sam Houston, San Antonio, 78234, TX, USA.,59th Medical Wing, JBSA Lackland, San Antonio, 78234, TX, USA
| | - Ryan A Curtis
- San Antonio Military Medical Center, JBSA Fort Sam Houston, San Antonio, 78234, TX, USA
| | - Cord W Cunningham
- San Antonio Military Medical Center, JBSA Fort Sam Houston, San Antonio, 78234, TX, USA
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13
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Breeding J, Hamp T, Grealy R, Nair P, Iyer A, Kawanishi Y. Effects of extracorporeal membrane oxygenation pump flow, backflow cannulae, mean arterial blood pressure, and pulse pressure on Doppler-derived flow velocities of the lower limbs in patients on peripheral veno-arterial extracorporeal membrane oxygenation: A pilot study. Aust Crit Care 2018; 32:206-212. [PMID: 29858038 DOI: 10.1016/j.aucc.2018.04.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 03/19/2018] [Accepted: 04/14/2018] [Indexed: 10/16/2022] Open
Abstract
BACKGROUND Reported rates of limb ischaemia on peripheral veno-arterial extracorporeal membrane oxygenation (pVA ECMO) vary from 1-52%. OBJECTIVES Primary: To explore (i) the feasibility for appropriately trained intensive care unit staff to measure Doppler derived flow velocities of the lower limbs for patients on pVA ECMO; and (ii) whether these measurements are clinically useful. Secondary: explore the relationship between ECMO pump flow, backflow cannulae (BFC) properties, mean arterial blood pressure (MAP), and pulse pressure on flow velocities. METHOD Inclusion criteria: age>18 years, on pVA ECMO >24 hours. EXCLUSION CRITERIA any guardianship limitations and patients without a BFC. Serial patients receiving pVA-ECMO over a 10 month period had Doppler derived flow velocities of the lower limbs sampled. Simultaneously, other pertinent parameters were recorded. 80% inclusion was considered clinically feasible. Study personnel were asked for feedback regarding the ease and usefulness of studies. RESULTS 15 of 17 patients were included: 88% inclusion. Mean peak systolic velocity (PSV) in the cannulated limb was 31 ± 29 cm/s in the dorsalis pedis (DP) and 27 ± 18 cm/s posterior tibial (PT). Similar flows were recorded in the non-cannulated limbs (DP 34 ± 29 cm/s, PT 44 ± 36 cm/s; P > 0.05). PSV was positively correlated with pulse pressure in cannulated and non-cannulated limbs respectively (r=0.63, P < 0.05; r=0.67 and P < 0.05). There was no significant correlation between PSV and MAP. ECMO pump flow and BFC were negatively correlated with PSV (r=-0.51, P < 0.05; r=-0.43, P < 0.05). CONCLUSION It is generally feasible for ICU staff to measure flow velocities of the lower limbs for patients on pVA ECMO. It remains unclear how clinically useful these measurements are. Doppler derived flow velocities of arteries of the lower limbs of patients on pVA ECMO appear different to non-ECMO patients. PSV in the lower limbs of patients on pVA ECMO seems to be more related to pulse pressure than to other haemodynamic parameters.
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Affiliation(s)
- Jeff Breeding
- St Vincent's Hospital Sydney, 390 Victoria St, Darlinghurst, NSW, 2010, Australia.
| | - Thomas Hamp
- St Vincent's Hospital Sydney, 390 Victoria St, Darlinghurst, NSW, 2010, Australia
| | - Robert Grealy
- St Vincent's Hospital Sydney, 390 Victoria St, Darlinghurst, NSW, 2010, Australia
| | - Priya Nair
- St Vincent's Hospital Sydney, 390 Victoria St, Darlinghurst, NSW, 2010, Australia; Garvin Institute for Medical Research, 384 Victoria St, Darlinghurst, NSW, 2010, Australia; University of New South Wales, High St, Kensington, NSW, 2052, Australia
| | - Arjun Iyer
- St Vincent's Hospital Sydney, 390 Victoria St, Darlinghurst, NSW, 2010, Australia
| | - Yujiro Kawanishi
- St Vincent's Hospital Sydney, 390 Victoria St, Darlinghurst, NSW, 2010, Australia
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14
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Gliemann L, Mortensen SP, Hellsten Y. Methods for the determination of skeletal muscle blood flow: development, strengths and limitations. Eur J Appl Physiol 2018; 118:1081-1094. [PMID: 29756164 DOI: 10.1007/s00421-018-3880-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 03/26/2018] [Indexed: 11/26/2022]
Abstract
Since the first measurements of limb blood flow at rest and during nerve stimulation were conducted in the late 1800s, a number of methods have been developed for the determination of limb and skeletal muscle blood flow in humans. The methods, which have been applied in the study of aspects such as blood flow regulation, oxygen uptake and metabolism, differ in terms of strengths and degree of limitations but most have advantages for specific settings. The purpose of this review is to describe the origin and the basic principles of the methods, important aspects and requirements of the procedures. One of the earliest methods, venous occlusion plethysmography, is a noninvasive method which still is extensively used and which provides similar values as other more direct blood flow methods such as ultrasound Doppler. The constant infusion thermodilution method remains the most appropriate for the determination of blood flow during maximal exercise. For resting blood flow and light-to-moderate exercise, the non-invasive ultrasound Doppler methodology, if handled by a skilled operator, is recommendable. Positron emission tomography with radiolabeled water is an advanced method which requires highly sophisticated equipment and allows for the determination of muscle-specific blood flow, regional blood flows and estimate of blood flow heterogeneity within a muscle. Finally, the contrast-enhanced ultrasound method holds promise for assessment of muscle-specific blood flow, but the interpretation of the data obtained remains uncertain. Currently lacking is high-resolution methods for continuous visualization and monitoring of the skeletal muscle microcirculation in humans.
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Affiliation(s)
- Lasse Gliemann
- Department of Nutrition Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Stefan P Mortensen
- Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark
| | - Ylva Hellsten
- Department of Nutrition Exercise and Sports, University of Copenhagen, Copenhagen, Denmark.
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15
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Neville RF, Gupta SK, Kuraguntla DJ. Initial in vitro and in vivo evaluation of a self-monitoring prosthetic bypass graft. J Vasc Surg 2016; 65:1793-1801. [PMID: 27693031 DOI: 10.1016/j.jvs.2016.06.114] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 06/27/2016] [Indexed: 12/22/2022]
Abstract
OBJECTIVE Prosthetic grafts used for lower extremity revascularization and dialysis access fail because of hyperplastic stenosis and thrombosis. Graft surveillance is advocated to monitor function; however, graft failure can occur between episodic examinations. An innovative sensor with wireless, microchip technology allows automated surveillance with assessment of graft function using a "cloud"-based algorithm. We performed proof-of-concept experiments with in vitro and in vivo models to assess the feasibility such a real-time graft surveillance system. METHODS A self-monitoring graft system was evaluated consisting of a prosthetic conduit of expanded polytetrafluoroethylene and a sensor unit, and a microsensor, microelectronics, battery, and remote processor with a monitor. The sensor unit was integrated on the extraluminal surface of expanded polytetrafluoroethylene grafts without compromise to the lumen of the conduit. The grafts were tested in vitro in a pulsatile, recirculating flow system under physiologic flow parameters. The hemodynamic parameters were varied to assess the ability to obtain wireless signal acquisition reflecting real-time flow properties in vitro. Segments of custom tubing with reduced diameters were inserted into the model to mimic stenosis proximal and distal to the grafts. After characterization of the initial data, the self-monitoring grafts were implanted in an ovine carotid model to assess proof of concept in vivo with 30-day follow-up of signal acquisition as well as arteriographic and histologic analysis. RESULTS In vitro flow data demonstrated the device was able to determine factors related to prosthetic graft function under varied hemodynamic flow conditions. Wireless signal acquisition using Bluetooth technology (Bluetooth SIG, Inc, Kirkland, Wash) allowed remote data analysis reflecting graft flow parameters through changes in microsensor voltage and frequency. Waveform analysis was applied to construct an algorithm using proprietary software and determine a parameter for graft flow characteristics. This algorithm allowed determination of the degree of stenosis and location of stenosis location (proximal or distal) for display on a remote monitor in real time. Subsequent in vivo experiments confirmed the ability of the system to generate signal acquisition through skin and soft tissue under biologic conditions with no arteriographic stenosis and a favorable healing response at 30-day harvest. CONCLUSIONS Initial in vitro and in vivo experiments demonstrate the ability for a self-monitoring graft system to remotely monitor hemodynamic parameters reflecting graft function using wireless data transmission. This automated system shows promise to deliver real-time data that can be analyzed by cloud-based algorithms alerting the clinician of a change in graft function or development of stenosis for further diagnostic study or intervention before graft failure.
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Affiliation(s)
- Richard F Neville
- Division of Vascular Surgery, Department of Surgery, George Washington University Medical Faculty Associates, Washington, D.C..
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16
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Geist RE, DuBois CH, Nichols TC, Caughey MC, Merricks EP, Raymer R, Gallippi CM. Experimental Validation of ARFI Surveillance of Subcutaneous Hemorrhage (ASSH) Using Calibrated Infusions in a Tissue-Mimicking Model and Dogs. ULTRASONIC IMAGING 2016; 38:346-58. [PMID: 26614530 PMCID: PMC5719486 DOI: 10.1177/0161734615617940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Acoustic radiation force impulse (ARFI) Surveillance of Subcutaneous Hemorrhage (ASSH) has been previously demonstrated to differentiate bleeding phenotype and responses to therapy in dogs and humans, but to date, the method has lacked experimental validation. This work explores experimental validation of ASSH in a poroelastic tissue-mimic and in vivo in dogs. The experimental design exploits calibrated flow rates and infusion durations of evaporated milk in tofu or heparinized autologous blood in dogs. The validation approach enables controlled comparisons of ASSH-derived bleeding rate (BR) and time to hemostasis (TTH) metrics. In tissue-mimicking experiments, halving the calibrated flow rate yielded ASSH-derived BRs that decreased by 44% to 48%. Furthermore, for calibrated flow durations of 5.0 minutes and 7.0 minutes, average ASSH-derived TTH was 5.2 minutes and 7.0 minutes, respectively, with ASSH predicting the correct TTH in 78% of trials. In dogs undergoing calibrated autologous blood infusion, ASSH measured a 3-minute increase in TTH, corresponding to the same increase in the calibrated flow duration. For a measured 5% decrease in autologous infusion flow rate, ASSH detected a 7% decrease in BR. These tissue-mimicking and in vivo preclinical experimental validation studies suggest the ASSH BR and TTH measures reflect bleeding dynamics.
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Affiliation(s)
- Rebecca E Geist
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA and North Carolina State University, Raleigh, NC, USA
| | - Chase H DuBois
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA and North Carolina State University, Raleigh, NC, USA Cortical Metrics, LLC, Chapel Hill, NC, USA and North Carolina State University, Raleigh, NC USA
| | - Timothy C Nichols
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Melissa C Caughey
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Elizabeth P Merricks
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Robin Raymer
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Caterina M Gallippi
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA and North Carolina State University, Raleigh, NC, USA
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17
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Shimamoto H, Kito H, Kawazoe K, Fujita T, Shimamoto Y. Quantitative Pulsed Doppler Measurement of Arterial Blood Flows in Humans. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/153857449202600510] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Doppler flowmetry was assessed in 11 adult patients whose admission diag noses included aneurysm of the aorta or dissections. During surgery, regional blood flows of the left common carotid artery, terminal aorta, common iliac artery, external iliac artery, or common femoral artery were measured by Dop pler method and electromagnetic flowmeter. Eighty-four arterial flow determi nation were obtained from the 11 patients studied. On comparison of simultaneous electromagnetic and Doppler measurements of blood flow, an ex cellent correlation (r=0.93) was found between the two methods. The slope of the regression line was about 0.587. Regional blood flows were measured with Doppler flowmetry in another 11 patients. The values of the left common carotid, celiac, superior mesenteric, and terminal aortic flows were 255 ± 59, 618 ± 384, 670 ± 380, and 810 ± 325 mL/min, respectively. This method seems to be valua ble clinically in quantitative measurements of arterial flows in humans.
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Affiliation(s)
- Hiroyuki Shimamoto
- Department of Cardiovascular Surgery, National Cardiovascular Center, Suita
| | - Hiroyuki Kito
- Department of Cardiovascular Surgery, National Cardiovascular Center, Suita
| | - Kohei Kawazoe
- Department of Cardiovascular Surgery, National Cardiovascular Center, Suita
| | - Tsuyoshi Fujita
- Department of Cardiovascular Surgery, National Cardiovascular Center, Suita
| | - Yoriko Shimamoto
- Department of Internal Medicine, Nakamura Hospital, Hiroshima, Japan
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18
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Henrique Rossi F, Puech-Leão P, Mitsuro Izukawa N, Pontes Junior SC, Massamitsu Kambara A, Mattos Barreto RB, Hassan Saleh M, Gomes Ferreira Petisco AC, Vasconcelos Oliveira LA. Color-Flow Duplex Hemodynamic Assessment of Runoff in Ischemic Lower Limb Revascularization. Vascular 2016; 14:149-55. [PMID: 16956487 DOI: 10.2310/6670.2006.00031] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The objective of this study was to evaluate the existence of hemodynamic arterial flow correlation between preoperative duplex scanning (DS) and intraoperative direct outflow resistance (IDOR) measurements in ischemic lower limb revascularization. Sixty-eight ischemic lower limbs were submitted to preoperative DS. Anatomic and hemodynamic arterial characteristics of the outflow system were recorded, and the results were considered in the distal anastomosis placement site decision making. IDOR measurements were obtained at the same arterial segment, and Pearson's correlation coefficient test was performed to study the preoperative DS power in predicting the intraoperative outflow resistance. DS was technically satisfactory and helped define the distal anastomosis site in 93.2% of the cases (supragenicular popliteal artery, 19 [27.9%]; infragenicular popliteal artery, 10 [14.7%]; crural artery, 31 [57.4%]). A positive correlation could be found between preoperative DS and IDOR (0.450; p < .001). This correlation was particularly powerful in the crural artery (0.715; p < .001) when compared with the popliteal arterial segment (0.237; p = .192). Preoperative DS may help define the best distal arterial and outflow segment to be revascularized based on anatomic and hemodynamic parameters. There is a positive flow correlation between preoperative DS and IDOR that seems to be stronger in crural revascularization surgery.
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Affiliation(s)
- Fabio Henrique Rossi
- Department of Vascular Surgery, Dante Pazzanese Cardiovascular Institute, São Paulo, Brazil.
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19
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Go MR, Masterson L, Vaccaro PS. Axillary-Femoral Bypass May Provide Inadequate Distal Perfusion Compared with In-Line Large Diameter Aortic Reconstruction. Ann Vasc Surg 2015; 30:158.e11-4. [PMID: 26476270 DOI: 10.1016/j.avsg.2015.09.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 08/11/2015] [Accepted: 09/09/2015] [Indexed: 11/19/2022]
Abstract
Axillary-femoral bypass is sometimes performed for complex aortoiliac occlusive disease in patients unfit for aortic surgery or in those with aortic infection. Typically, older patients with medical comorbidities that commonly accompany atherosclerotic or aneurysmal disease are involved and can tolerate the theoretic risk of limited flow volume associated with long, small diameter, axillary-femoral grafts. However, a subset of younger, healthier, more vigorous patients outside the typical atherosclerotic or aneurysmal demographic occasionally come to axillary-femoral bypass and may experience symptoms of distal hypoperfusion if flow volumes cannot meet demand. We present a series of patients with primary aortic infection treated with aortic ligation and axillary-femoral bypass, who then progressed to symptoms of visceral, spinal, or extremity ischemia from inadequate distal perfusion.
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Affiliation(s)
- Michael R Go
- Division of Vascular Diseases and Surgery, The Ohio State University Medical Center, Columbus, OH.
| | - Loren Masterson
- Division of Vascular Diseases and Surgery, The Ohio State University Medical Center, Columbus, OH
| | - Patrick S Vaccaro
- Division of Vascular Diseases and Surgery, The Ohio State University Medical Center, Columbus, OH
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20
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Weddell JC, Kwack J, Imoukhuede PI, Masud A. Hemodynamic analysis in an idealized artery tree: differences in wall shear stress between Newtonian and non-Newtonian blood models. PLoS One 2015; 10:e0124575. [PMID: 25897758 PMCID: PMC4405589 DOI: 10.1371/journal.pone.0124575] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 03/14/2015] [Indexed: 11/19/2022] Open
Abstract
Development of many conditions and disorders, such as atherosclerosis and stroke, are dependent upon hemodynamic forces. To accurately predict and prevent these conditions and disorders hemodynamic forces must be properly mapped. Here we compare a shear-rate dependent fluid (SDF) constitutive model, based on the works by Yasuda et al in 1981, against a Newtonian model of blood. We verify our stabilized finite element numerical method with the benchmark lid-driven cavity flow problem. Numerical simulations show that the Newtonian model gives similar velocity profiles in the 2-dimensional cavity given different height and width dimensions, given the same Reynolds number. Conversely, the SDF model gave dissimilar velocity profiles, differing from the Newtonian velocity profiles by up to 25% in velocity magnitudes. This difference can affect estimation in platelet distribution within blood vessels or magnetic nanoparticle delivery. Wall shear stress (WSS) is an important quantity involved in vascular remodeling through integrin and adhesion molecule mechanotransduction. The SDF model gave a 7.3-fold greater WSS than the Newtonian model at the top of the 3-dimensional cavity. The SDF model gave a 37.7-fold greater WSS than the Newtonian model at artery walls located immediately after bifurcations in the idealized femoral artery tree. The pressure drop across arteries reveals arterial sections highly resistive to flow which correlates with stenosis formation. Numerical simulations give the pressure drop across the idealized femoral artery tree with the SDF model which is approximately 2.3-fold higher than with the Newtonian model. In atherosclerotic lesion models, the SDF model gives over 1 Pa higher WSS than the Newtonian model, a difference correlated with over twice as many adherent monocytes to endothelial cells from the Newtonian model compared to the SDF model.
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Affiliation(s)
- Jared C. Weddell
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, United States of America
- * E-mail:
| | - JaeHyuk Kwack
- Department of Civil Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, United States of America
| | - P. I. Imoukhuede
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, United States of America
| | - Arif Masud
- Department of Civil Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, United States of America
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Hansen PM, Olesen JB, Pihl MJ, Lange T, Heerwagen S, Pedersen MM, Rix M, Lönn L, Jensen JA, Nielsen MB. Volume flow in arteriovenous fistulas using vector velocity ultrasound. ULTRASOUND IN MEDICINE & BIOLOGY 2014; 40:2707-2714. [PMID: 25282482 DOI: 10.1016/j.ultrasmedbio.2014.06.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 04/18/2014] [Accepted: 06/03/2014] [Indexed: 06/03/2023]
Abstract
Volume flow in arteriovenous fistulas for hemodialysis was measured using the angle-independent ultrasound technique Vector Flow Imaging and compared with flow measurements using the ultrasound dilution technique during dialysis. Using an UltraView 800 ultrasound scanner (BK Medical, Herlev, Denmark) with a linear transducer, 20 arteriovenous fistulas were scanned directly on the most superficial part of the fistula just before dialysis. Vector Flow Imaging volume flow was estimated with two different approaches, using the maximum and the average flow velocities detected in the fistula. Flow was estimated to be 242 mL/min and 404 mL/min lower than the ultrasound dilution technique estimate, depending on the approach. The standard deviations of the two Vector Flow Imaging approaches were 175.9 mL/min and 164.8 mL/min compared with a standard deviation of 136.9 mL/min using the ultrasound dilution technique. The study supports that Vector Flow Imaging is applicable for volume flow measurements.
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Affiliation(s)
- Peter Møller Hansen
- Department of Radiology, Copenhagen University Hospital, Copenhagen, Denmark.
| | - Jacob Bjerring Olesen
- Center for Fast Ultrasound Imaging, Department of Elec. Eng., Technical University of Denmark, Lyngby, Denmark
| | - Michael Johannes Pihl
- Center for Fast Ultrasound Imaging, Department of Elec. Eng., Technical University of Denmark, Lyngby, Denmark
| | - Theis Lange
- Department of Biostatistics, University of Copenhagen, Copenhagen, Denmark
| | - Søren Heerwagen
- Department of Radiology, Copenhagen University Hospital, Copenhagen, Denmark
| | | | - Marianne Rix
- Department of Nephrology, Copenhagen University Hospital, Copenhagen, Denmark
| | - Lars Lönn
- Department of Radiology, Copenhagen University Hospital, Copenhagen, Denmark; Department of Vascular Surgery, Copenhagen University Hospital, Copenhagen, Denmark
| | - Jørgen Arendt Jensen
- Center for Fast Ultrasound Imaging, Department of Elec. Eng., Technical University of Denmark, Lyngby, Denmark
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Müller LO, Toro EF. A global multiscale mathematical model for the human circulation with emphasis on the venous system. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2014; 30:681-725. [PMID: 24431098 DOI: 10.1002/cnm.2622] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 10/04/2013] [Accepted: 11/20/2013] [Indexed: 05/29/2023]
Abstract
We present a global, closed-loop, multiscale mathematical model for the human circulation including the arterial system, the venous system, the heart, the pulmonary circulation and the microcirculation. A distinctive feature of our model is the detailed description of the venous system, particularly for intracranial and extracranial veins. Medium to large vessels are described by one-dimensional hyperbolic systems while the rest of the components are described by zero-dimensional models represented by differential-algebraic equations. Robust, high-order accurate numerical methodology is implemented for solving the hyperbolic equations, which are adopted from a recent reformulation that includes variable material properties. Because of the large intersubject variability of the venous system, we perform a patient-specific characterization of major veins of the head and neck using MRI data. Computational results are carefully validated using published data for the arterial system and most regions of the venous system. For head and neck veins, validation is carried out through a detailed comparison of simulation results against patient-specific phase-contrast MRI flow quantification data. A merit of our model is its global, closed-loop character; the imposition of highly artificial boundary conditions is avoided. Applications in mind include a vast range of medical conditions. Of particular interest is the study of some neurodegenerative diseases, whose venous haemodynamic connection has recently been identified by medical researchers.
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Affiliation(s)
- Lucas O Müller
- Laboratory of Applied Mathematics, Department of Civil, Environmental and Mechanical Engineering, University of Trento, Via Mesiano 77, I-38100, Trento, Italy
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23
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Osada T, Murase N, Kime R, Katsumura T, Rådegran G. Blood flow dynamics in the limb conduit artery during dynamic knee extensor exercise assessed by continuous Doppler ultrasound measurements. JOURNAL OF PHYSICAL FITNESS AND SPORTS MEDICINE 2014. [DOI: 10.7600/jpfsm.3.409] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Calibrated image-derived input functions for the determination of the metabolic uptake rate of glucose with [18F]-FDG PET. Nucl Med Commun 2013; 35:353-61. [PMID: 24335879 PMCID: PMC3940375 DOI: 10.1097/mnm.0000000000000063] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Purpose We investigated the use of a simple calibration method to remove bias in previously proposed approaches to image-derived input functions (IDIFs) when used to calculate the metabolic uptake rate of glucose (Km) from dynamic [18F]-FDG PET scans of the thigh. Our objective was to obtain nonbiased, low-variance Km values without blood sampling. Materials and methods We evaluated eight previously proposed IDIF methods. Km values derived from these IDIFs were compared with Km values calculated from the arterial blood samples (gold standard). We used linear regression to extract calibration parameters to remove bias. Following calibration, cross-validation and bootstrapping were used to estimate the mean square error and variance. Results Three of the previously proposed methods failed mainly because of zero-crossings of the IDIF. The remaining five methods were improved by calibration, yielding unbiased Km values. The method with the lowest SD yielded an SD of 0.0017/min – that is, below 10% of the muscle Km value in this study. Conclusion Previously proposed IDIF methods can be improved by using a simple calibration procedure. The calibration procedure may be used in other studies, thus obviating the need for arterial blood sampling, once the calibration parameters have been established in a subgroup of participants. The method has potential for use in other parts of the body as it is robust with regard to partial volume effects.
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Affiliation(s)
- Bina Ahmed
- From the Department of Medicine, University of New Mexico, Albuquerque (B.A.); Department of Medicine, University of Vermont, Burlington (H.L.D)
| | - Harold L. Dauerman
- From the Department of Medicine, University of New Mexico, Albuquerque (B.A.); Department of Medicine, University of Vermont, Burlington (H.L.D)
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Wang AS, Liang DH, Bech F, Lee JT, Zarins CK, Zhou W, Taylor CA. Validation of a power law model in upper extremity vessels: potential application in ultrasound bleed detection. ULTRASOUND IN MEDICINE & BIOLOGY 2012; 38:692-701. [PMID: 22341050 DOI: 10.1016/j.ultrasmedbio.2011.12.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2010] [Revised: 12/10/2011] [Accepted: 12/19/2011] [Indexed: 05/31/2023]
Abstract
Vascular ultrasound can provide quick and reliable diagnosis of arterial bleeding but it requires trained and experienced personnel. Development of automated sonographic bleed detection methods would potentially be valuable for trauma management in the field. We propose a detection method that (1) measures blood flow in a trauma victim, (2) determines the victim's expected normal limb arterial flow using a power law biofluid model where flow is proportional to the vessel diameter taken to a power of k and (3) quantifies the difference between measured and expected flow with a novel metric, flow split deviation (FSD). FSD was devised to give a quantitative value for the likelihood of arterial bleeding and validated in human upper extremities. We used ultrasound to demonstrate that the power law with k = 2.75 appropriately described the normal brachial artery bifurcation geometry and adequately determined the expected normal flows. Our metric was then applied to three-dimensional (3-D) computational models of forearm bleeding and on dialysis patients undergoing surgical construction of wrist arteriovenous fistulas. Computational models showed that larger sized arterial defects produced larger flow deviations. FSD values were statistically higher (paired t-test) for arms with fistulas than those without, with average FSDs of 0.41 ± 0.12 and 0.047 ± 0.021 (mean ± SD), respectively. The average of the differences was 0.36 ± 0.12 (mean ± SD).
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Affiliation(s)
- Aaron S Wang
- Department of Bioengineering, Stanford University, Stanford, CA 94305-5233, USA.
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Wang AS, Abilez OJ, Zarins CK, Taylor CA, Liang DH. Power Law as a Method for Ultrasound Detection of Internal Bleeding: In Vivo Rabbit Validation. IEEE Trans Biomed Eng 2010; 57:2870-5. [DOI: 10.1109/tbme.2010.2058803] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Griffin M, Nicolaides AN, Bond D, Geroulakos G, Kalodiki E. The efficacy of a new stimulation technology to increase venous flow and prevent venous stasis. Eur J Vasc Endovasc Surg 2010; 40:766-71. [PMID: 20650668 DOI: 10.1016/j.ejvs.2010.06.019] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2010] [Accepted: 06/20/2010] [Indexed: 11/27/2022]
Abstract
OBJECTIVES Electrical stimulation of calf muscles has been shown to be effective in prevention of DVT. The aim was to determine: (a) dependence of venous blood velocity and ejected volume on the rates of stimulated calf contractions: (b) clinical factors affecting efficacy in healthy individuals. METHODS The maximum intensity stimulus tolerated was applied to calves of 24 volunteers. In popliteal veins, peak systolic velocities (PSV), ejected volume per individual stimulus (stroke volume SV) and ejected total volume flow per minute (TVF) of expelled blood were determined using ultrasound. Stimulation rates from 2 to 120 beats per minute (bpm) were applied. RESULTS Mean baseline popliteal PSV was 10 cm/s. For stimulation rates between 2 and 8 bpm, the PSV was 10 times higher and reached 96-105 cm/s. Stroke volume (SV) per individual stimulus decreased in a similar fashion. With increasing rates of stimulation the TVF increased by a factor of 12 times (from 20 ml/min to 240 ml/min). CONCLUSION Electrical stimulation is an effective method of activating the calf muscle pump. Enhancements of popliteal blood velocity and volume flow are key factors in the prevention of venous stasis and DVT. Further studies are justified to determine the stimulation rates in those with a compromised venous system.
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Affiliation(s)
- M Griffin
- The Vascular Noninvasive Screening and Diagnostic Centre, 30 Weymouth Street, London W1G 7BS, UK.
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Siesky B, Harris A, Kagemann L, Moore D, Werne A, Sheets CW, Garzozi HJ. In vitro simulation of the first technique for non-invasive measurement of volumetric ophthalmic artery blood flow in humans. Ophthalmic Surg Lasers Imaging Retina 2010; 41:375-82. [PMID: 20507024 DOI: 10.3928/15428877-20100430-13] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/27/2009] [Indexed: 11/20/2022]
Abstract
BACKGROUND AND OBJECTIVE To evaluate the accuracy, reproducibility, and variability of volumetric flow measurements taken by color Doppler imaging ultrasound, using an in vitro "phantom" model to simulate the ophthalmic artery. MATERIALS AND METHODS An agar flow phantom with two wall-less lumens was constructed to simulate the ophthalmic artery. Velocity and volumetric flow measurements were taken for various flow rates and ultrasound probe positions. The measurements were analyzed for accuracy, reproducibility, and variability. RESULTS Velocity measurements were more accurate than flow measurements (8 of 24 vs 3 of 24 accurate trials). The average coefficient of variation for volumetric blood flow was 11.4% (n = 120). Volumetric flow significantly correlated with velocity (R(2) = 0.408, n = 600, P < .001). The highest correlation was achieved using the large lumen with the probe held at 75 degrees , offset to the flow (R(2) = 0.862, n = 75). CONCLUSION Based on an in vitro model, non-invasive color Doppler imaging recordings of volumetric flow measurements in the ophthalmic artery significantly correlated with velocity and higher correlations were found using the larger lumens, although the data showed a lack of high accuracy in measurements of flow and velocity.
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Affiliation(s)
- Brent Siesky
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, USA
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Menzies-Gow NJ, Bailey SR, Katz LM, Marr CM, Elliott J. Endotoxin-induced digital vasoconstriction in horses: associated changes in plasma concentrations of vasoconstrictor mediators. Equine Vet J 2010; 36:273-8. [PMID: 15147137 DOI: 10.2746/0425164044877260] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
REASONS FOR PERFORMING STUDY Lipopolysaccharide (LPS) infusion reduces digital perfusion, but the mediators responsible remain undetermined. OBJECTIVES To identify vasoconstrictor mediators released following LPS infusion and relate their appearance in plasma to digital blood flow alterations. METHODS Blood flow in the lateral digital vessels of 6 Thoroughbred horses, following a 30 min infusion of LPS (E. coli 055:B5; 30 ng/kg), was measured using Doppler ultrasonography. Concomitant measurements of hoof wall and coronary band surface temperatures (HWST and CBST) were made. Serial blood samples were collected and plasma LPS, tumour necrosis factor alpha (TNFalpha), 5-HT, thromboxane B2 (TxB2) and endothelin measured. RESULTS Plasma LPS concentrations reached a maximum of 13.2 pg/ml during the infusion, followed by an increase in plasma TNFalpha concentration. Digital arterial and venous blood flow decreased by 43 and 63%, respectively; HWST and CBST similarly decreased. Systemic blood pressure remained unaltered. Plasma concentrations of TxB2 and 5-HT increased, coinciding with the onset of digital hypoperfusion. Plasma endothelin concentrations remained unchanged. CONCLUSIONS The temporal relationship between the onset of digital hypoperfusion and increases in plasma 5-HT and TxB2 concentrations is consistent with these platelet-derived mediators being associated with LPS-induced laminitis. POTENTIAL RELEVANCE These experimental data support the use of anti-platelet therapy in the prevention of laminitis associated with endotoxaemic conditions.
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Affiliation(s)
- N J Menzies-Gow
- Department of Veterinary Clinical Sciences, Royal Veterinary College, Hatfield, Hertfordshire AL9 7TA, UK
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Rossi FH, Leão PP, Izukawa NM, Prakasan AK. Classificação angiográfica na revascularização do membro inferior isquêmico: pode a angiografia definir a resistência do leito receptor do enxerto? J Vasc Bras 2009. [DOI: 10.1590/s1677-54492009000300004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
CONTEXTO: A arteriografia é muitas vezes utilizada como único método pré-operatório para a definição da conduta terapêutica na revascularização do membro isquêmico, seja ela realizada através de angioplastia transluminal, ou de cirurgia convencional. Ainda hoje, sua utilização é assunto de debate. OBJETIVO: Comparar um método de classificação arteriográfica simples com estudos hemodinâmicos pré e intraoperatórios do leito arterial isquêmico a ser revascularizado, com o objetivo de verificar seu poder para definir a resistência desse leito arterial. MÉTODOS: Foram analisadas 68 cirurgias de revascularização de membros inferiores isquêmicos realizadas no período de julho de 1999 a julho de 2004 no Setor de Cirurgia Vascular do Instituto Dante Pazzanese de Cardiologia. As características do leito arterial receptor do enxerto foram estudadas e comparadas através de método de classificação arteriográfica pré-operatória proposto pelos autores, análise hemodinâmica pré-operatória por eco-Doppler colorido e intraoperatória por medidas diretas de vazão, pressão e resistência. RESULTADOS: Foram observados índices de correlação de Spearman positivos (p < 0,05) entre o sistema de classificação arteriográfica pré-operatória proposto e as medidas hemodinâmicas ultrassonográficas pré-operatórias de volume de fluxo sanguíneo (p = 0,035) e as medidas diretas intraoperatórias de vazão (p = 0,006), pressão (p = 0,037) e resistência (p = 0,006). CONCLUSÃO: O método de classificação arteriográfica pré-operatória proposto pode definir a resistência do leito arterial a ser revascularizado e auxiliar na definição da conduta e do prognóstico da revascularização do membro inferior isquêmico.
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Menzies-Gow NJ, Sepulveda MF, Bailey SR, Cunningham FM, Elliott J. Roles of thromboxane A2and 5-hydroxytryptamine in endotoxin-induced digital vasoconstriction in horses. Am J Vet Res 2008; 69:199-207. [DOI: 10.2460/ajvr.69.2.199] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Menzies-Gow NJ, Marr CM. REPEATABILITY OF DOPPLER ULTRASONOGRAPHIC MEASUREMENT OF EQUINE DIGITAL BLOOD FLOW. Vet Radiol Ultrasound 2007; 48:281-5. [PMID: 17508518 DOI: 10.1111/j.1740-8261.2007.00243.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The repeatability and sensitivity of Doppler ultrasonographic measurement of lateral digital arterial and venous blood flow has not been previously determined. Doppler ultrasonography was used to measure blood flow within the forelimb lateral digital vessels in one normal adult Thoroughbred horse on six occasions and in six normal adult Thoroughbred horses on three occasions, each occasion being at least 1 h apart, to determine the within- and between-horse variation. The values obtained from the right and left lateral digital vessels did not differ significantly. The within-horse coefficients of variation (CV) for arterial and venous measurements were all acceptable (< 11%); the between-horse CV were acceptable (< 7%) for all parameters except TaVa (average velocity of first peak of arterial waveform) and TaVb (average velocity of remainder of arterial waveform). The within-horse intraclass correlation coefficients (ICC) demonstrated excellent repeatability (> or = 0.71) for all parameters except venous diameter; the between-horse ICC demonstrated good to excellent repeatability (> or = 0.67) for all parameters except TaVb. Doppler ultrasonography can detect differences of 0.005 and 0.01 ml/ min in digital arterial and venous flow, respectively, using measurements from six horses on three occasions (80% power; P < 0.05). Thus, the technique is sufficiently repeatable and sensitive to be able to detect changes in flow during different physiological or pathological states or following pharmacologic intervention.
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Affiliation(s)
- Nicola J Menzies-Gow
- Department of Veterinary Clinical Sciences, Royal Veterinary College, Hatfield, Hawkshead Lane, North Mymms, Hertfordshire AL9 7TA, UK.
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Galili O, Mannheim D, Rapaport S, Karmeli R. A novel intermittent mechanical compression device for stasis prevention in the lower limbs during limited mobility situations. Thromb Res 2007; 121:37-41. [PMID: 17439822 DOI: 10.1016/j.thromres.2007.02.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2006] [Revised: 02/20/2007] [Accepted: 02/28/2007] [Indexed: 11/16/2022]
Abstract
INTRODUCTION Intermittent pneumatic mechanical compression is commonly applied to obviate venous stasis in patients with increased risk of thromboembolism. Aviafit is a small battery-operated intermittent compression device using a patented mechanical, non-pneumatic technology. Our objective was to examine its ability to prevent venous stasis. MATERIALS AND METHODS Doppler ultrasonography was used to determine venous hemodynamics of 22 healthy volunteers in both legs, before applying the Aviafit to one randomly selected leg, upon device activation and after 30 min. Each measurement provided values for peak flow velocity (PFV) and total volume flow (TVF). RESULTS The PFV values were significantly higher in the treated leg upon activation of the Aviafit and at 30 min, compared to the baseline value and to the PFV of the untreated leg at the corresponding time points (p<0.001 for each). The TVF increased in the treated leg from baseline of 48 ml/min to 56 ml/min at T0, and then gradually decreased, similar to the untreated leg. At T30, 64% of the treated legs had a higher TVF than their untreated counterparts. CONCLUSIONS The lightweight, battery-operated and user-friendly Aviafit can provide the same hemodynamic benefits as larger conventional intermittent pneumatic compression devices. Its potential advantages for prophylaxis of thromboembolism and increased compliance in rehabilitation and homecare, and for use during long periods of immobility such as during flights, are evident.
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Affiliation(s)
- Offer Galili
- Department of Vascular Surgery, Carmel Medical Center, Haifa, 34362, Israel.
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Lindenberger M, Länne T. Sex-related effects on venous compliance and capillary filtration in the lower limb. Am J Physiol Regul Integr Comp Physiol 2007; 292:R852-9. [PMID: 17038441 DOI: 10.1152/ajpregu.00394.2006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Recent studies in humans have suggested sex differences in venous compliance of the lower limb, with lower compliance in women. Capillary fluid filtration could, however, be a confounder in the evaluation of venous compliance. The venous capacitance and capillary filtration response in the calves of 12 women (23.2 ± 0.5 years) and 16 men (22.9 ± 0.5 years) were studied during 8 min lower body negative pressure (LBNP) of 11, 22, and 44 mmHg. Calf venous compliance is dependent on pressure and was determined using the first derivative of a quadratic regression equation that described the capacitance-pressure relationship [compliance = β1 + (2·β2· transmural pressure)]. We found a lower venous compliance in women at low transmural pressures, and the venous capacitance in men was increased ( P < 0.05). However, the difference in compliance between sexes was reduced and not seen at higher transmural pressures. Net capillary fluid filtration and capillary filtration coefficient (CFC) were greater in women than in men during LBNP ( P < 0.05). Furthermore, calf volume increase (capacitance response + total capillary filtration) during LBNP was equivalent in both sexes. When total capillary filtration was not subtracted from the calf capacitance response in the calculation of venous compliance, the sex differences disappeared, emphasizing that venous compliance measurement should be corrected for the contribution of CFC.
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Affiliation(s)
- M Lindenberger
- Division of Physiology, Department of Medicine and Care, Linköping University, SE 58185 Linköping, Sweden
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Tanaka H, Shimizu S, Ohmori F, Muraoka Y, Kumagai M, Yoshizawa M, Kagaya A. Increases in blood flow and shear stress to nonworking limbs during incremental exercise. Med Sci Sports Exerc 2006; 38:81-5. [PMID: 16394957 DOI: 10.1249/01.mss.0000191166.81789.de] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE Regular exercise augments endothelium-dependent vasodilatory capacity in the vasculature located in the nonworking limbs. We determined whether blood flow as well as shear stress would change in inactive limbs during acute incremental exercise. METHODS Eight young healthy female subjects performed graded exercise on arm and leg cycle ergometers that had been modified to minimize the movement of nonworking limbs and to facilitate the placement of Doppler transducers. Both brachial and femoral blood flow was monitored using Doppler ultrasonography. EMG activity was also measured to document that there was no muscular activity in nonworking muscles. RESULTS During leg exercise, brachial blood flow and calculated shear stress gradually and curvilinearly increased (P < 0.05). At the peak work rate, there was an approximately fourfold increase in blood flow in the brachial artery (19 +/- 6 vs 77 +/- 16 mL x min(-1)). Femoral blood flow and calculated shear stress increased progressively and linearly during arm exercise (P < 0.05). CONCLUSION We concluded that blood flow to the nonworking limbs increases markedly in proportion to the work intensity. These results suggest that the conduit arteries in the nonworking limbs are exposed to increases in blood flow and shear stress during exercise.
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Affiliation(s)
- Hirofumi Tanaka
- Research Institute of Physical Fitness, Japan Women's College of Physical Education, Setagaya, Tokyo, Japan.
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Osada T. Exercise-related time course of pulsatility index in brachial artery following forearm exercise assessed by Doppler ultrasound. TOHOKU J EXP MED 2005; 203:241-52. [PMID: 15297729 DOI: 10.1620/tjem.203.241] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
At rest, vascular reactivity assessed by the changes in pulsatility index (PI) is one indicator of vessel stenosis in some clinical/basic science research. However, all types of vessel stenosis do not show an alteration in the PI, because flow perfusion may be maintained by the development of collateral vessels such as in severe arterial stenosis or non-severe arterial stenosis. Therefore at rest, changes in the PI may not always be a precise indicator of vessel stenosis. However, a few studies have used the PI following exercise, which may provide additional information on hemodynamics. The purpose of the present study was to examine the exercise-related time course of the PI in the brachial artery after ischemic or non-ischemic isometric handgrip exercise (IHE) using Doppler ultrasound, and to determine the potential use of this parameter as an indicator of vascular disease. Ten healthy young male subjects performed IHE at 10% and 30% of maximum voluntary contraction (MVC) for 2-minutes (min) with or without arterial occlusion (AO), or 2-min of AO alone. Following each 2-min session, PI was determined during the 5-min recovery period. A significant difference in the recovery PI was observed between IHE, ischemic IHE, as well as AO alone. Exercise with AO significantly increased the reduction in the PI compared to exercise alone, or AO alone, at both 10% and 30%MVC. These results suggest, exercise-induced changes in the time course of the PI during recovery may potentially be a useful diagnostic tool. Exercise-induced ischemic state may potentially be a useful indicator for detecting arteriovascular disease, even if it is not detected by AO alone.
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Affiliation(s)
- Takuya Osada
- Department of Preventive Medicine and Public Health, Tokyo Medical University, Shinjuku, Shinjuku-ku, Japan.
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Lee HG, Yum MK. Fourier transformation of arterial Doppler waveforms of the lower extremity. JOURNAL OF CLINICAL ULTRASOUND : JCU 2004; 32:277-285. [PMID: 15211673 DOI: 10.1002/jcu.20040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
PURPOSE Although it is well known that the normal, triphasic pulsatile arterial Doppler waveform changes in shape as flow is impaired, interpretation of the waveform has largely been subjective. We aimed to describe the Doppler waveforms of the lower extremity objectively using Fourier transformation. METHODS Sixty-eight zero-crossing detector arterial recordings from 25 lower extremities were grouped as follows: group 1, no ischemic symptoms with an ankle-brachial index (ABI) > 0.9 (n = 17, 8 limbs); group 2, no ischemic symptoms with ABI < 0.9 (n = 18, 5 limbs); group 3, symptoms of claudication (n = 19, 7 limbs); group 4, rest pain or tissue loss (n = 14, 5 limbs). The waveforms were Fourier transformed and their amplitudes and phases were compared up to the third harmonic (H3). RESULTS Amplitudes of both the fundamental (H1) and second harmonic (H2) were predominant in group 1. In contrast, amplitudes of the H2 and H3 decreased with altered flow (p < 0.0001 for group 1 versus others). The phases of the H1 and H2 were delayed with altered flow (p < 0.05 for group 1 versus others). Phases of the H1 were different between group 2 and 4 (p < 0.05). The difference of phase between the H3 and H1 was shortened with altered flow (p < 0.05 for group 1 or 2 versus group 4). Multivariate analysis revealed that the relative amplitudes of the H2 and H3, the phases of the H1 and H2, and the relative phase of the H3 were significant discriminators among the groups. CONCLUSION Abnormal waveforms could be characterized by the predominant amplitude of the H1, phase delay of the H1 and H2, and shortening of the relative phase of the H3. These parameters may be useful in the evaluation of Doppler waveforms in patients with peripheral arterial disease.
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Affiliation(s)
- Hong Gi Lee
- Department of Surgery, Hanyang University Kuri Hospital, 249-1 Kyomun-dong, Kuri-si, Kyunggi-do 471-020, South Korea
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Abstract
OBJECTIVE To summarize the currently published scientific evidence for the venous flow effects of mechanical devices, particularly intermittent pneumatic compression, and the relation to prevention of deep vein thrombosis (DVT). SUMMARY BACKGROUND DATA While intermittent pneumatic compression is an established method of DVT prophylaxis, the variety of systems that are available can use very different compression techniques and sequences. In order for appropriate choices to be made to provide the optimum protection for patients, the general performance of systems, and physiological effects of particular properties, must be analyzed objectively. METHODS Medline was searched from 1970 to 2002, and all relevant papers were searched for further appropriate references. Papers were selected for inclusion when they addressed specifically the questions posed in this review. RESULTS All the major types of intermittent compression systems are successful in emptying deep veins of the lower limb and preventing stasis in a variety of subject groups. Compression stockings appear to function more by preventing distension of veins. Rapid inflation, high pressures, and graded sequential intermittent compression systems will have particular augmentation profiles, but there is no evidence that such features improve the prophylactic ability of the system. CONCLUSIONS The most important factors in selecting a mechanical prophylactic system, particularly during and after surgery, are patient compliance and the appropriateness of the site of compression. There is no evidence that the peak venous velocity produced by a system is a valid measure of medical performance.
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Affiliation(s)
- Rhys J Morris
- Department of Medical Physics and Bioengineering, University of Wales College of Medicine, Cardiff, Wales.
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Klein WM, Bartels LW, Bax L, van der Graaf Y, Mali WPTM. Magnetic resonance imaging measurement of blood volume flow in peripheral arteries in healthy subjects. J Vasc Surg 2003; 38:1060-6. [PMID: 14603218 DOI: 10.1016/s0741-5214(03)00706-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
OBJECTIVE Peripheral arterial disease results in insufficient blood supply to the leg. Assessment of blood flow may provide information about severity of the disease. Magnetic resonance imaging (MRI) has potential use for simple, fast quantitative blood flow measurement. We investigated normal blood flow values for age and sex in the common femoral artery and popliteal artery in 50 healthy volunteers. In addition, we examined reproducibility and determinants of blood flow. METHODS We performed cardiac-triggered phase-contrast quantitative flow measurements in the common femoral artery and popliteal artery, and MRI of the calves in 50 healthy volunteers (age, 26-80 years). Ten persons underwent MRI three times, to analyze reproducibility. RESULTS All measurements were technically successful. Mean blood flow was 353 mL/min in the femoral artery and 61.9 mL/min in the popliteal artery. Coefficient of variation of femoral measurements was 16%, and of popliteal measurements was 19%. Femoral blood flow was significantly related to age and sex. Popliteal blood flow was significantly related to calf muscle volume, adjusted for age and sex. CONCLUSION Normal values for blood flow to the legs are presented. The measurements have reasonable reproducibility. Blood flow to the legs depends on age, sex, and calf muscle volume.
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Affiliation(s)
- Willemijn M Klein
- Department of Radilogy, University Medical Center, Utrecht, The Netherlands
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Huonker M, Schmid A, Schmidt-Trucksass A, Grathwohl D, Keul J. Size and blood flow of central and peripheral arteries in highly trained able-bodied and disabled athletes. J Appl Physiol (1985) 2003; 95:685-91. [PMID: 12433857 DOI: 10.1152/japplphysiol.00710.2001] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In a cross-sectional study, central and peripheral arteries were investigated noninvasively in high-performance athletes and in untrained subjects. The diastolic inner vessel diameter (D) of the thoracic and abdominal aorta, the subclavian artery (Sub), and common femoral artery (Fem) were determined by duplex sonography in 18 able-bodied professional tennis players, 34 able-bodied elite road cyclist athletes, 26 athletes with paraplegia, 17 below-knee amputated athletes, and 30 able-bodied, untrained subjects. The vessel cross-sectional areas (CSA) were set in relation to body surface area (BSA), and the cross-section index (CS-index = CSA/BSA) was calculated. Volumetric blood flow was determined in Sub and Fem via a pulsed-wave Doppler system and was set in relation to heart rate to calculate the stroke flow. A significantly increased D of Sub was found in the racket arm of able-bodied tennis players compared with the opposite arm (19%). Fem of able-bodied road cyclist athletes and of the intact limb in below-knee amputated athletes showed similar increases. D of Fem was lower in athletes with paraplegia (37%) and in below-knee amputated athletes proximal to the lesion (21%) compared with able-bodied, untrained subjects; CS-indexes were reduced 57 and 31%, respectively. Athletes with paraplegia demonstrated a larger D (19%) and a larger CS-index in Sub (54%) than able-bodied, untrained subjects. No significant differences in D and CS-indexes of the thoracic and abdominal aorta were found between any of the groups. The changes measured in Sub and Fem were associated with corresponding alterations in blood flow and stroke flow in all groups. The study suggests that the size and blood flow volume of the proximal limb arteries are adjusted to the metabolic needs of the corresponding extremity musculature and underscore the impact of exercise training or disuse on the structure and the function of the arterial system.
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Affiliation(s)
- M Huonker
- Medical University Hospital, Freiburg, Department of Prevention, Rehabilitation and Sportsmedicine, Freiburg, Germany.
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Osada T, Katsumura T, Murase N, Sako T, Higuchi H, Kime R, Hamaoka T, Shimomitsu T. Post-exercise Hyperemia after Ischemic and Non-ischemic Isometric Handgrip Exercise. ACTA ACUST UNITED AC 2003; 22:299-309. [PMID: 14646265 DOI: 10.2114/jpa.22.299] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Post-exercise related time course of muscle oxygenation during recovery provides valuable information on peripheral vascular disease. The purpose of the present study was to examine post-exercise hyperemia (forearm blood flow; FBF, Doppler ultrasound) assessed by peak FBF, excess FBF and the time constant for FBF (FBF(Tc)) following isometric handgrip exercise (IHE). Post-exercise hyperemia was assessed in an ischemic and non-ischemic state at different exercise intensities and durations. Peak FBF and excess FBF were defined as the maximum FBF during recovery, and the total amount of FBF volume, respectively. FBF(Tc) represents the time to reach approximately 37% of the change in FBF between peak FBF and resting FBF (delta peak FBF). Ten subjects performed IHE at "10% and 30% maximum voluntary contraction (MVC)" for 2 min with or without arterial occlusion (AO), followed by 2 min of AO alone (Study I). In Study II, six subjects performed 30%MVC-IHE with AO for "100%, 66%, 33% and 10% of the exhausted exercise duration" (time to exhaustion). In Study I, although peak FBF and excess FBF were significantly higher in ischemic than non-ischemic IHE for both 10% and 30%MVC (p<0.05), FBF(Tc) was similar in the ischemic and non-ischemic conditions. The peak FBF, excess FBF and FBF(Tc) were all significantly higher at 30% than at 10%MVC (p<0.05). In Study II, the peak FBF and excess FBF increased linearly compared to the absolute and relative exercise durations for ischemic IHE. FBF(Tc) increased exponentially when compared to the absolute and relative exercise durations. These data suggest the ischemic exercise has a larger hyperemic response compared to the non-ischemic exercise. In conclusion, the peak FBF, excess FBF and FBF(Tc) seen during post-exercise hyperemia are closely correlated with exercise intensity and duration, not only in non-ischemic, but also in the ischemic exercise. In combination with the ischemic exercise, these parameters could potentially prove to be valuable indicators of peripheral vascular disease.
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Affiliation(s)
- Takuya Osada
- Department of Preventive Medicine and Public Health, Tokyo Medical University, Japan.
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Orge F, Harris A, Kagemann L, Kopecky K, Sheets CW, Rechtman E, Zalish M. The first technique for non-invasive measurements of volumetric ophthalmic artery blood flow in humans. Br J Ophthalmol 2002; 86:1216-9. [PMID: 12386070 PMCID: PMC1771372 DOI: 10.1136/bjo.86.11.1216] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AIM To validate the first non-invasive measurements of volumetric ophthalmic artery blood flow in humans. METHODS The ophthalmic arteries of healthy normal adults were examined by Advanced Technology Laboratories (ATL, a subsidiary of Phillips Medical Systems Inc) high definition imaging (HDI) 5000 colour Doppler imaging ultrasound with a 5-12 MHZ probe. A group of 14 subjects for experiment 1 and a group of 10 subjects for experiments 2 and 3 were selected, with the examined eye chosen randomly. Peak systolic velocities (PSV) and end diastolic velocities (EDV) of the ophthalmic artery and central retinal artery were measured and recorded. Cineloops (cinegraphic videos) of the ophthalmic arteries were then recorded with the ATL HDI 5000 and values for ophthalmic artery blood flow were produced offline using experimental analysis software. Multiple regression analysis was used to compare blood flow measurements with PSV and EDV measurements in the ophthalmic artery. In two follow up experiments, intraobserver variation in obtaining cineloops and the interanalyser variability in cineloop analysis were studied. RESULTS Volumetric flow correlated with ophthalmic artery PSV and EDV (p = 0.02, r(2) = 0.5). There was no correlation with the cental retinal artery. The intraobserver coefficient of variation in obtaining cineloops was 29.89% for blood flow, 19.07% for diameter, and 22.27% for velocity. The coefficients of variation of the measurements of the two cineloop analysers were 40.21% for blood flow, 22.71% for diameter, and 26.34% for velocity. CONCLUSION Cineloop analysis produces ophthalmic artery flow measurements which correlate with PSV and EDV, suggesting validity. The intraobserver variation and cineloop analyser variation were found to be in the acceptable range.
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Affiliation(s)
- F Orge
- Departments of Ophthalmology and Physiology, Indiana University School of Medicine, Indianapolis IN, USA
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Gerrits HL, de Haan A, Sargeant AJ, van Langen H, Hopman MT. Peripheral vascular changes after electrically stimulated cycle training in people with spinal cord injury. Arch Phys Med Rehabil 2001; 82:832-9. [PMID: 11387591 DOI: 10.1053/apmr.2001.23305] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To test whether a short period of training leads to adaptations in the cross-sectional area of large conduit arteries and improved blood flow to the paralyzed legs of individuals with spinal cord injury (SCI). DESIGN Before-after trial. SETTING Rehabilitation center, academic medical center. PARTICIPANTS Nine men with spinal cord lesions. INTERVENTION Six weeks of cycling using a functional electrically stimulated leg cycle ergometer (FES-LCE). MAIN OUTCOME MEASURES Longitudinal images and simultaneous velocity spectra were measured in the common carotid (CA) and femoral (FA) arteries using quantitative duplex Doppler ultrasound examination. Arterial diameters, peak systolic inflow volumes (PSIVs), mean inflow volumes (MIVs), and a velocity index (VI), representing the peripheral resistance, were obtained at rest. PSIVs and VI were obtained during 3 minutes of hyperemia following 20 minutes of FA occlusion. RESULTS Training resulted in significant increases in diameter (p < .01), PSIVs (p < .01), and MIVs (p < .05), and reduced VI (p < .01) of the FA, whereas values in the CA remained unchanged. Postocclusive hyperemic responses were augmented, indicated by significantly higher PSIVs (p <.01) and a trend toward lower VI. CONCLUSION Six weeks of FES-LCE training increased the cross-sectional area of large conduit arteries and improved blood flow to the paralyzed legs of individuals with SCI.
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Affiliation(s)
- H L Gerrits
- Institute for Fundamental and Clinical Human Movement Sciences, Vrije University Amsterdam, Amsterdam, the Netherlands.
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Perko MJ. Duplex ultrasound for assessment of superior mesenteric artery blood flow. Eur J Vasc Endovasc Surg 2001; 21:106-17. [PMID: 11237782 DOI: 10.1053/ejvs.2001.1313] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Duplex ultrasound (DU) is recognised as a valuable tool for the assessment of blood flow in many vascular territories. The application of this technique to the superior mesenteric artery (SMA) has increased rapidly throughout the last decade. The purpose of this review is to collate currently available information on the utility of SMA DU, both in terms of research and clinical practice. Research investigations have revealed low intra- and interobserver variability in the estimation of Doppler variables, while reliable evaluation of B-mode dimensions requires repeated measurements. SMA blood flow velocity has been found to be dependent upon changes in central haemodynamics and in peripheral resistance, which was documented in studies with hypotension, medication and post-prandially. Food intake induces mesenteric vasorelaxation reflected by a 10-fold increase in the diastolic velocity. This feature has been utilised in studies on mesenteric physiology, which confirmed parasympathetic activity during hypovolaemia, and showed that exercise increases splanchnic resistance and reduces its blood flow following a 50% reduction in the hepato-splenic and a 25% reduction in the mesenteric blood flow. Clinical studies have documented high sensitivity and specificity of DU in detection of disease in splanchnic arteries. Diastolic velocity was found to be the most accurate indicator of SMA stenosis, while an absent Doppler signal from a well visualised vessel has been found to be a reliable predictor of occlusion. The high predictive value of DU in the detection of mesenteric artery disease, together with its simplicity and non-invasiveness, suggests that DU should take precedence over arteriography in both clinical practice and laboratory investigations.
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Affiliation(s)
- M J Perko
- Department of Vascular Surgery and Cardiothoracic Surgery, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
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Pfister ME, Andrews RT, Pavcnik D, Uchida BT, Rösch J. Effects of intraarterial thrombin in the swine model. J Vasc Interv Radiol 2001; 12:235-45. [PMID: 11265889 DOI: 10.1016/s1051-0443(07)61831-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
PURPOSE To evaluate the effects of catheter-directed thrombin in the peripheral arterial circulation of swine. MATERIALS AND METHODS Thrombin was injected into a single femoral artery in 20 domestic swine. Each of five animals from four dose groups received 50, 150, 250, or 1,000 U as a single dose. Bilateral femoral arterial flow was monitored for as long as 4 hours and evaluated relative to baseline and contralateral limb flow. Interval arteriographic results were evaluated by segmental patency and a numeric angiographic score. RESULTS Mean baseline flow was 136 mL/min +/- 44, with an internal arterial diameter of 3.4 mm +/- 0.5. A transient increase in blood flow after thrombin administration was followed by diminished flow and thrombosis. These findings varied directly with dose and inversely with baseline flow. Angiographic and flow abnormalities generally improved with time and recovery was generally better in swine that received 50 or 1,000 U than in other groups. However, one animal that received 1,000 U (13.2 U/mL/min) developed stable, complete limb thrombosis. The degree of recovery varied with thrombin dose and thrombus location. At doses greater than 50 U (0.33 U/mL/min +/- 0.05), abnormalities were commonly persistent. Animals receiving the 150-U dose (1.33 U/mL/min +/- 0.41) had a higher incidence of persistent distal occlusion. Distal occlusions were less likely to resolve than proximal occlusions. CONCLUSIONS The effect of intraarterial thrombin is directly related to dose and inversely related to baseline blood flow. In swine, a threshold for significant flow disruption and thrombosis exists above a dose of 50 U (0.33 U/mL/min +/- 0.05). A threshold dose for irreversible occlusion may also exist. Although small amounts of thrombin in a high-flow vessel may not cause significant complication, administration into the arterial circulation should be avoided.
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Affiliation(s)
- M E Pfister
- Dotter Interventional Institute, Oregon Health Sciences University, University Hospital South, Portland 97201-3098, USA
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Wu HD, Katz SD, Beniaminovitz A, Khan T, DiTullio MR, Homma S. Assessment of endothelium-mediated vasodilation of the peripheral circulation by transcutaneous ultrasonography and venous occlusion plethysmography. Heart Vessels 2000; 14:143-8. [PMID: 10776807 DOI: 10.1007/bf02482298] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Transcutaneous ultrasonography is a non-invasive technique with the ability to measure the volumetric blood flow of the peripheral circulation. Peripheral blood flow can be determined by high-resolution imaging of vessel diameter coupled with Doppler assessment of flow velocity. This method, however, has not been validated in vivo. Accordingly, brachial artery flow in response to intraarterial infusion of vasodilators was assessed by ultrasonography in 16 healthy subjects and compared to values obtained simultaneously by venous occlusion plethysmography. Blood flow calculated from ultrasound-derived vessel diameter and flow velocity was found to highly correlate with plethysmographic flow, with r values ranging from 0.83 to 0.99. Using this ultrasound technique combined with plethysmography, the response of conduit and resistance vessels to endothelium-mediated vasodilation was characterized. Doppler velocity rose dramatically with endothelium-dependent acetylcholine (970%), but only modestly with endothelium-independent vasodilators, nitroglycerin (292%) and nitroprusside (340%). Despite eliciting the greatest overall forearm flow response, acetylcholine resulted in a smaller increase in conduit diameter (15.4%) than nitroglycerin (21.8%), and only a comparable change than nitroprusside (14.6%). Taken together, these results suggest that acetylcholine acts predominantly on resistance vessels, whereas nitrovasodilators affect mainly conduit vessels. In summary, transcutaneous ultrasonography can be used reliably to assess flow changes in the peripheral circulation. Combined with plethysmography, this technique is useful for determining the relative contribution of conduit and resistance vessels to peripheral flow, particularly in the assessment of endothelium-mediated vasodilation.
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Affiliation(s)
- H D Wu
- Division of Cardiology, Columbia University, College of Physicians and Surgeons, New York, NY 10032, USA
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Raisis AL, Young LE, Meire H, Walsh K, Taylor PM, Lekeux P. Repeatability of Doppler ultrasound measurements of hindlimb blood flow in halothane anaesthetised horses. Equine Vet J 2000; 32:239-46. [PMID: 10836480 DOI: 10.2746/042516400776563662] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The purpose of this study was to determine the repeatability of femoral blood flow recorded using Doppler ultrasound in anaesthetised horses. Doppler ultrasound of the femoral artery and vein was performed in 6 horses anaesthetised with halothane and positioned in left lateral recumbency. Velocity spectra, recorded using low pulse repetition frequency, were used to calculate time-averaged mean velocity (TAV), velocity of component a (TaVa), velocity of component b (TaVb), volumetric flow, early diastolic deceleration slope (EDDS) and pulsatility index (PI). Within-patient variability was determined for sequential Doppler measurements recorded during a single standardised anaesthetic episode. Within-patient variability was also determined for Doppler and cardiovascular measurements recorded during 4 separate standardised anaesthetic episodes performed at intervals of at least one month. Within-patient variation during a single anaesthetic episode was small. Coefficients of variation (cv) were <12.5% for arterial measurements and <17% for venous measurements. Intraclass correlation coefficient was >0.75 for all measurements. No significant change was observed in measurements of cardiovascular function suggesting that within-patient variation observed during a single anaesthetic episode was due to measurement error. In contrast, within-patient variation during 4 separate anaesthetic episodes was marked (cv>17%) for most Doppler measurements obtained from arteries and veins. Variation in measurements of cardiovascular function were marked (cv>20%), suggesting that there is marked biological variation in central and peripheral observed. Further studies are warranted to determine the ability of this technique to detect differences in blood flow during administration of different anaesthetic agents.
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Affiliation(s)
- A L Raisis
- The Centre for Equine Studies, The Animal Health Trust, Newmarket, Suffolk, UK
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Bønnelykke Sørensen V, Wroblewski H, Galatius S, Haunsø S, Kastrup J. Assessment of continuous skeletal muscle blood flow during exercise in humans. Microvasc Res 2000; 59:301-9. [PMID: 10684736 DOI: 10.1006/mvre.1999.2219] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The ability to measure regional blood flow from exercising skeletal muscles is of great interest. However, noninvasive techniques such as venous occlusion plethysmography and pulsed Doppler duplex ultrasonography only allow determination of blood flow at rest. The aim of our study was to investigate the influence of position on continuous measured skeletal muscle blood flow response in the upright and supine positions during graded maximal exercise by means of the local (133)Xenon washout technique with portable CdTe(Cl) detectors. Fifteen healthy subjects (8 women and 7 men, mean age 46 +/- 11 years) performed graded maximal bicycle exercise in both supine and upright positions in random order on 2 subsequent days. Blood flow in the musculus tibialis anterior was measured using the local (133)Xenon washout technique. A total of 55-110 MBq of (133)Xenon dissolved in isotonic saline was injected intramuscularly and the gamma emission was registered by light-weight portable CdTe(Cl) detectors. During supine exercise skeletal muscle blood flow increased continuously with increasing work load. However, during upright exercise blood flow increased only at the initial three work loads, then it decreased gradually. Immediately after exercise blood flow returned to preexercise values for both positions. The skeletal muscle blood flow at maximum work load for each subject was 74% (relative flow values) (P < 0.05) higher in the supine compared with the upright position. There was no significant difference in absolute or relative blood flow values at similar time points. Exercise time was longer in the supine (1345 +/- 548 s) compared with the upright position (1148 +/- 453 s) (P < 0.005). The local (133)Xenon washout technique with portable CdTe(Cl) detectors allows continuous determination of skeletal muscle blood flow during graded bicycle exercise in supine and upright positions. Furthermore, blood flow at maximum work load and exercise time was increased in supine compared with upright exercise.
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Delis KT, Labropoulos N, Nicolaides AN, Glenville B, Stansby G. Effect of intermittent pneumatic foot compression on popliteal artery haemodynamics. Eur J Vasc Endovasc Surg 2000; 19:270-7. [PMID: 10753690 DOI: 10.1053/ejvs.1999.1028] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE the aim was to investigate the effect of intermittent pneumatic foot compression (IPC(foot)) on popliteal artery haemodynamics in normal individuals and in patients with intermittent claudication due to peripheral vascular disease (PVD) (Fontaine stage II). MATERIAL AND METHODS popliteal artery volume flow [vFl], pulsatility index [PI], mean velocity [mV], peak systolic [PSV] and end diastolic velocity [EDV], in 25 limbs of 20 normal subjects and 40 limbs of 32 stable claudicants were obtained in the sitting position before, during and within 30 seconds after the application of IPC(foot)(applied pressure: 120 mmHg; inflation time: 3 seconds; deflation time: 17 seconds) using colour-flow duplex imaging (CFDI). The reproducibility of flow velocity estimations using CFDI in the horizontal [hor] (recovery) and sitting [sit] positions was evaluated in 20 limbs of normal controls and 20 limbs of claudicants. RESULTS popliteal artery vFl, mV, PSV and PI measurements were performed with a coefficient of variation (CV) of less than 14.6% among claudicants and of less than 13.3% in normal subjects. EDV is the least reproducible parameter with an overall CV range of 10.2-21.5% in normal controls and 9.1-18.6% in arteriopaths. On application of IPC(foot)popliteal artery vFl increased by 111% in the control group (p<0.001) and by 51% in the claudicants (p<0.001). Within 30 seconds of the cessation of pump action flow decreased significantly in both groups (p<0.001), but maintained a significantly higher level than that at baseline (p<0. 001, in both groups). The mV, PSV and EDV showed a similar pattern of significant changes. Both in normals and claudicants, the PI decreased with IPC(foot)(p<0.001) and increased post-compression; however, it was significantly lower than baseline (p<0.005) within 30 seconds of impulse delivery. CONCLUSIONS current CFDI technology enables a reproducible estimation of popliteal artery flow velocities. IPC(foot)can significantly augment arterial calf inflow on an acute basis both in normals and claudicants. The increase of EDV and decrease of PI indicate that attenuation of peripheral resistance to flow is the main mechanism underlying the popliteal artery vFl enhancement on application of IPC(foot). Prospective trials on the long-term effect of IPC(foot)in the management of patients with PVD are indicated from the results of this study.
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Affiliation(s)
- K T Delis
- Irvine Laboratory for Cardiovascular Investigation and Research, Academic Vascular Surgery, London, Paddington, UK
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