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Tsivgoulis G, Safouris A, Alexandrov AV. Ultrasonography. Stroke 2022. [DOI: 10.1016/b978-0-323-69424-7.00046-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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2
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Nederhoed JH, Tjaberinga M, Otten RHJ, Evers JM, Musters RJP, Wisselink W, Yeung KK. Therapeutic Use of Microbubbles and Ultrasound in Acute Peripheral Arterial Thrombosis: A Systematic Review. ULTRASOUND IN MEDICINE & BIOLOGY 2021; 47:2821-2838. [PMID: 34272082 DOI: 10.1016/j.ultrasmedbio.2021.06.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 05/15/2021] [Accepted: 06/01/2021] [Indexed: 06/13/2023]
Abstract
Catheter-directed thrombolysis (CDT) for acute peripheral arterial occlusion is time consuming and carries a risk of major hemorrhage. Contrast-enhanced sonothrombolysis (CEST) might enhance outcomes compared with standard CDT. In the study described here, we systematically reviewed all in vivo studies on contrast-enhanced sonothrombolysis in a setting of arterial thrombosis. A systematic search of the PubMed, Embase, Cochrane Library and Web of Science databases was conducted. Two reviewers independently performed the study selection, quality assessment and data extraction. Primary outcomes were recanalization rate and thrombus weight. Secondary outcome was any possible adverse event. The 35 studies included in this review were conducted in four different (pre)clinical settings: ischemic stroke, myocardial infarction, (peripheral) arterial thrombosis and arteriovenous graft occlusion. Because of the high heterogeneity among the studies, it was not possible to conduct a meta-analysis. In almost all studies, recanalization rates were higher in the group that underwent a form of CEST. One study was terminated early because of a higher incidence of intracranial hemorrhage. Studies on CEST suggest that adding microbubbles and ultrasound to standard intra-arterial CDT is safe and might improve outcomes in acute peripheral arterial thrombosis. Further research is needed before CEST can be implemented in daily practice.
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Affiliation(s)
- Johanna H Nederhoed
- Department of Surgery, Amsterdam University Medical Centers (VUmc), Amsterdam, The Netherlands.
| | - Meike Tjaberinga
- Department of Surgery, Amsterdam University Medical Centers (VUmc), Amsterdam, The Netherlands
| | - René H J Otten
- Medical Library Vrije Universiteit, Amsterdam University Medical Centers (VUmc), Amsterdam, The Netherlands
| | - Josje M Evers
- Department of Surgery, Amsterdam University Medical Centers (VUmc), Amsterdam, The Netherlands
| | - René J P Musters
- Department of Physiology, Amsterdam University Medical Centers (VUmc), Amsterdam, The Netherlands
| | - Willem Wisselink
- Department of Surgery, Amsterdam University Medical Centers (VUmc), Amsterdam, The Netherlands
| | - Kak K Yeung
- Department of Surgery, Amsterdam University Medical Centers (VUmc), Amsterdam, The Netherlands; Department of Physiology, Amsterdam University Medical Centers (VUmc), Amsterdam, The Netherlands
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3
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Goel L, Jiang X. Advances in Sonothrombolysis Techniques Using Piezoelectric Transducers. SENSORS 2020; 20:s20051288. [PMID: 32120902 PMCID: PMC7085655 DOI: 10.3390/s20051288] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 02/21/2020] [Accepted: 02/24/2020] [Indexed: 12/11/2022]
Abstract
One of the great advancements in the applications of piezoelectric materials is the application for therapeutic medical ultrasound for sonothrombolysis. Sonothrombolysis is a promising ultrasound based technique to treat blood clots compared to conventional thrombolytic treatments or mechanical thrombectomy. Recent clinical trials using transcranial Doppler ultrasound, microbubble mediated sonothrombolysis, and catheter directed sonothrombolysis have shown promise. However, these conventional sonothrombolysis techniques still pose clinical safety limitations, preventing their application for standard of care. Recent advances in sonothrombolysis techniques including targeted and drug loaded microbubbles, phase change nanodroplets, high intensity focused ultrasound, histotripsy, and improved intravascular transducers, address some of the limitations of conventional sonothrombolysis treatments. Here, we review the strengths and limitations of these latest pre-clincial advancements for sonothrombolysis and their potential to improve clinical blood clot treatments.
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Affiliation(s)
- Leela Goel
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695-7910, USA;
- Joint Department of Biomedical Engineering, North Carolina State University and The University of North Carolina at Chapel Hill, Raleigh, NC 27695-7910, USA
| | - Xiaoning Jiang
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695-7910, USA;
- Correspondence: ; Tel.: +1-919-515-5240
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Drug-Loaded Microbubbles Combined with Ultrasound for Thrombolysis and Malignant Tumor Therapy. BIOMED RESEARCH INTERNATIONAL 2019; 2019:6792465. [PMID: 31662987 PMCID: PMC6791276 DOI: 10.1155/2019/6792465] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 07/22/2019] [Accepted: 09/14/2019] [Indexed: 12/14/2022]
Abstract
Cardiac-cerebral thrombosis and malignant tumor endanger the safety of human life seriously. Traditional chemotherapy drugs have side effects which restrict their applications. Drug-loaded microbubbles can be destroyed by ultrasound irradiation at the focus position and be used for thrombolysis and tumor therapy. Compared with traditional drug treatment, the drug-loaded microbubbles can be excited by ultrasound and release drugs to lesion sites, increasing the local drug concentration and the exposure dose to nonfocal regions, thus reducing the cytotoxicity and side effects of drugs. This article reviews the applications of drug-loaded microbubbles combined with ultrasound for thrombolysis and tumor therapy. We focus on highlighting the advantages of using this new technique for disease treatment and concluding with recommendations for future efforts on the applications of this technology.
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Acconcia CN, Leung BYC, Winch G, Wang J, Hynynen K, Goertz DE. Acoustic radiation force induced accumulation and dynamics of microbubbles on compliant surfaces. Phys Med Biol 2019; 64:135003. [PMID: 31082815 DOI: 10.1088/1361-6560/ab2163] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Ultrasound stimulated microbubbles have been shown to be capable of breaking up blood clots through micro-scale interactions occurring near the clot surface. However, only a small fraction of bubbles circulating in the bloodstream will be in close proximity to such boundaries, where they must be to elicit therapeutic effects. Here, the accumulation and subsequent behavior of microbubbles displaced from an overlying flow channel to a boundary under radiation forces were examined. Experimental data were acquired using a novel high speed microscopy configuration and simulations were conducted to provide insight into the accumulation process. There was broad agreement between experiments and simulations, both indicating that the size distribution and number of bubbles arriving at the boundary depended on channel flow rate, applied pressure, and bubble concentration. For example, higher flow rates and lower pressures favored the accumulation of larger bubbles relative to the native agent distribution. Moreover, bubble dynamics were dependent on the surface type, exhibiting rapid translation along agarose gel surfaces whereas on fibrin surfaces, they accumulated in localized regions inducing repetitive strain cycles. The results indicate that the process of bringing bubbles from within a vessel to a boundary is complex and should be an important consideration in the development of therapeutic applications such as sonothrombolysis.
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Affiliation(s)
- Christopher N Acconcia
- Department of Medical Biophysics, University of Toronto, Toronto, M5S 1A1, Canada. Sunnybrook Research Institute, 2075 Bayview Avenue, M4N 3M5, Toronto, Canada. These authors contributed equally
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Kutty S, Liu N, Zhou J, Xiao Y, Wu J, Danford D, Lof J, Xie F, Porter TR. ULTRASOUND INDUCED MICROBUBBLE CAVITATION FOR THE TREATMENT OF CATHETERIZATION INDUCED VASOSPASM. ACTA ACUST UNITED AC 2017; 2:748-756. [PMID: 29349360 PMCID: PMC5769697 DOI: 10.1016/j.jacbts.2017.07.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Shelby Kutty
- Division of Pediatric Cardiology, University of Nebraska College of Medicine/Children's Hospital & Medical Center, Omaha, NE
| | - Na Liu
- Division of Pediatric Cardiology, University of Nebraska College of Medicine/Children's Hospital & Medical Center, Omaha, NE.,Department of Cardiology and Cardiac Catheterization Lab, Second Xiangya Hospital, Central South University, Changsha, China
| | - Jia Zhou
- Division of Pediatric Cardiology, University of Nebraska College of Medicine/Children's Hospital & Medical Center, Omaha, NE.,Department of Ultrasonography, the First Affiliated Hospital of University of South China, Hengyang, China
| | - Yunbin Xiao
- Division of Pediatric Cardiology, University of Nebraska College of Medicine/Children's Hospital & Medical Center, Omaha, NE
| | - Juefei Wu
- Department of Internal Medicine, Section of Cardiology, University of Nebraska Medical Center, Omaha, NE
| | - David Danford
- Division of Pediatric Cardiology, University of Nebraska College of Medicine/Children's Hospital & Medical Center, Omaha, NE
| | - John Lof
- Department of Internal Medicine, Section of Cardiology, University of Nebraska Medical Center, Omaha, NE
| | - Feng Xie
- Department of Internal Medicine, Section of Cardiology, University of Nebraska Medical Center, Omaha, NE
| | - Thomas R Porter
- Department of Internal Medicine, Section of Cardiology, University of Nebraska Medical Center, Omaha, NE
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7
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Zhu Y, Guan L, Mu Y. Combined Low-Frequency Ultrasound and Urokinase-Containing Microbubbles in Treatment of Femoral Artery Thrombosis in a Rabbit Model. PLoS One 2016; 11:e0168909. [PMID: 28033371 PMCID: PMC5199065 DOI: 10.1371/journal.pone.0168909] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 12/08/2016] [Indexed: 11/19/2022] Open
Abstract
This paper aims to study the thrombolytic effect of low-frequency ultrasound combined with targeted urokinase-containing microbubble contrast agents on treatment of thrombosis in rabbit femoral artery; and to determine the optimal combination of parameters for achieving thrombolysis in this model. A biotinylated-avidin method was used to prepare microbubble contrast agents carrying urokinase and Arg-Gly-Asp-Ser (RGDS) peptides. Following femoral artery thrombosis in New Zealand white rabbits, microbubble contrast agents were injected intravenously, and ultrasonic exposure was applied. A 3 × 2 × 2 factorial table was applied to categorize the experimental animals based on different levels of combination of ultrasonic frequencies (Factor A: 1.6 MHz, 2.2 MHz, 2.8 MHz), doses of urokinase (Factor B: 90,000 IU/Kg, 180,000 IU/Kg) and ultrasound exposure time (Factor C: 30 min, 60 min). A total of 72 experimental animals were randomly divided into 12 groups (n = 6/group). Doppler techniques were used to assess blood flow in the distal end of the thrombotic femoral artery during the 120 minutes thrombolysis experiment. The rate of recanalization following thrombolysis was calculated, and thrombolytic efficacy was evaluated and compared. The thrombolytic recanalization rate for all experimental subjects after thrombolytic therapy was 68.1%. The optimal parameters for thrombolysis were determined to be 1) an ultrasound frequency of 2.2 MHz and 2) a 90,000 IU/kg dose of urokinase. Ultrasound exposure time (30 min vs. 60 min) had no significant effect on the thrombolytic effects. The combination of local low-frequency ultrasound radiation, targeted microbubbles, and thrombolytic urokinase induced thrombolysis of femoral artery thrombosis in a rabbit model. The ultrasonic frequency of 2.2 MHz and urokinase dose of 90,000 IU/kg induced optimal thrombolytic effects, while the application of either 30 min or 60 min of ultrasound exposure had similar effects.
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Affiliation(s)
- Yanping Zhu
- Department of Echocardiography, the First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, P.R. China
| | - Lina Guan
- Department of Echocardiography, the First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, P.R. China
| | - Yuming Mu
- Department of Echocardiography, the First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, P.R. China
- * E-mail:
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8
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Roos ST, Yu FT, Kamp O, Chen X, Villanueva FS, Pacella JJ. Sonoreperfusion Therapy Kinetics in Whole Blood Using Ultrasound, Microbubbles and Tissue Plasminogen Activator. ULTRASOUND IN MEDICINE & BIOLOGY 2016; 42:3001-3009. [PMID: 27687734 PMCID: PMC5328593 DOI: 10.1016/j.ultrasmedbio.2016.08.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 08/04/2016] [Accepted: 08/09/2016] [Indexed: 05/11/2023]
Abstract
Coronary intervention for myocardial infarction often results in microvascular embolization of thrombus. Sonoreperfusion therapy (SRP) using ultrasound and microbubbles restored perfusion in our in vitro flow model of microvascular obstruction. In this study, we assessed SRP efficacy using whole blood as the perfusate with and without tissue plasminogen activator (tPA). In a phantom vessel bearing a 40-μm-pore mesh to simulate the microvasculature, microthrombi were injected to cause microvascular obstruction and were treated using SRP. Without tPA, the lytic rate increased from 2.6 ± 1.5 mmHg/min with 1000-cycle pulses to 7.3 ± 3.2 mmHg/min with 5000-cycle ultrasound pulses (p < 0.01). The lytic index was similar for tPA-only ([2.0 ± 0.5] × 10-3 mmHg-1 min-1) and 5000 cycles without tPA ([2.3 ± 0.5] × 10-3 mmHg-1 min-1) (p = 0.5) but increased ([3.6 ± 0.8] × 10-3 mmHg-1 min-1) with tPA in conjunction with 5000-cycles ultrasound (p < 0.01). In conclusion, SRP restored microvascular perfusion in whole blood, SRP lytic rate in experiments without tPA increased with ultrasound pulse length and efficacy increased with the addition of tPA.
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Affiliation(s)
- Sebastiaan T Roos
- Center for Ultrasound Molecular Imaging and Therapeutics, University of Pittsburgh Medical Center, Heart and Vascular Institute, Pittsburgh, Pennsylvania, USA; Department of Cardiology and Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, Amsterdam, The Netherlands; Interuniversity Cardiology Institute of the Netherlands (ICIN), Utrecht, The Netherlands
| | - François T Yu
- Center for Ultrasound Molecular Imaging and Therapeutics, University of Pittsburgh Medical Center, Heart and Vascular Institute, Pittsburgh, Pennsylvania, USA
| | - Otto Kamp
- Department of Cardiology and Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, Amsterdam, The Netherlands; Interuniversity Cardiology Institute of the Netherlands (ICIN), Utrecht, The Netherlands
| | - Xucai Chen
- Center for Ultrasound Molecular Imaging and Therapeutics, University of Pittsburgh Medical Center, Heart and Vascular Institute, Pittsburgh, Pennsylvania, USA
| | - Flordeliza S Villanueva
- Center for Ultrasound Molecular Imaging and Therapeutics, University of Pittsburgh Medical Center, Heart and Vascular Institute, Pittsburgh, Pennsylvania, USA
| | - John J Pacella
- Center for Ultrasound Molecular Imaging and Therapeutics, University of Pittsburgh Medical Center, Heart and Vascular Institute, Pittsburgh, Pennsylvania, USA.
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Abstract
Thrombo-occlusive disease is a leading cause of morbidity and mortality. In this chapter, the use of ultrasound to accelerate clot breakdown alone or in combination with thrombolytic drugs will be reported. Primary thrombus formation during cardiovascular disease and standard treatment methods will be discussed. Mechanisms for ultrasound enhancement of thrombolysis, including thermal heating, radiation force, and cavitation, will be reviewed. Finally, in-vitro, in-vivo and clinical evidence of enhanced thrombolytic efficacy with ultrasound will be presented and discussed.
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Affiliation(s)
- Kenneth B Bader
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, College of Medicine, University of Cincinnati, Cincinnati, OH, USA
| | - Guillaume Bouchoux
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, College of Medicine, University of Cincinnati, Cincinnati, OH, USA
| | - Christy K Holland
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, College of Medicine, University of Cincinnati, Cincinnati, OH, USA.
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10
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Haršány M, Tsivgoulis G, Alexandrov AV. Ultrasonography. Stroke 2016. [DOI: 10.1016/b978-0-323-29544-4.00046-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Pacella JJ, Brands J, Schnatz FG, Black JJ, Chen X, Villanueva FS. Treatment of microvascular micro-embolization using microbubbles and long-tone-burst ultrasound: an in vivo study. ULTRASOUND IN MEDICINE & BIOLOGY 2015; 41:456-64. [PMID: 25542487 PMCID: PMC4428565 DOI: 10.1016/j.ultrasmedbio.2014.09.033] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 09/23/2014] [Accepted: 09/30/2014] [Indexed: 05/06/2023]
Abstract
Despite epicardial coronary artery reperfusion by percutaneous coronary intervention, distal micro-embolization into the coronary microcirculation limits myocardial salvage during acute myocardial infarction. Thrombolysis using ultrasound and microbubbles (sonothrombolysis) is an approach that induces microbubble oscillations to cause clot disruption and restore perfusion. We sought to determine whether this technique could restore impaired tissue perfusion caused by thrombotic microvascular obstruction. In 16 rats, an imaging transducer was placed on the biceps femoris muscle, perpendicular to a single-element 1-MHz treatment transducer. Ultrasound contrast perfusion imaging was performed at baseline and after micro-embolization. Therapeutic ultrasound (5000 cycles, pulse repetition frequency = 0.33 Hz, 1.5 MPa) was delivered to nine rats for two 10-min sessions during intra-arterial infusion of lipid-encapsulated microbubbles; seven control rats received no ultrasound-microbubble therapy. Ultrasound contrast perfusion imaging was repeated after each treatment or control period, and microvascular volume was measured as peak video intensity. There was a 90% decrease in video intensity after micro-embolization (from 8.6 ± 4.8 to 0.7 ± 0.8 dB, p < 0.01). The first and second ultrasound-microbubble sessions were respectively followed by video intensity increases of 5.8 ± 5.1 and 8.7 ± 5.7 dB (p < 0.01, compared with micro-embolization). The first and second control sessions, respectively, resulted in no significant increase in video intensity (2.4 ± 2.3 and 3.6 ± 4.9) compared with micro-embolization (0.6 ± 0.7 dB). We have developed an in vivo model that simulates the distal thrombotic microvascular obstruction that occurs after primary percutaneous coronary intervention. Long-pulse-length ultrasound with microbubbles has a therapeutic effect on microvascular perfusion and may be a valuable adjunct to reperfusion therapy for acute myocardial infarction.
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Affiliation(s)
- John J Pacella
- Center for Ultrasound and Molecular Imaging and Therapeutics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
| | - Judith Brands
- Center for Ultrasound and Molecular Imaging and Therapeutics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Frederick G Schnatz
- Center for Ultrasound and Molecular Imaging and Therapeutics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - John J Black
- Center for Ultrasound and Molecular Imaging and Therapeutics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Xucai Chen
- Center for Ultrasound and Molecular Imaging and Therapeutics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Flordeliza S Villanueva
- Center for Ultrasound and Molecular Imaging and Therapeutics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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El-Sherbiny IM, Elkholi IE, Yacoub MH. Tissue plasminogen activator-based clot busting: Controlled delivery approaches. Glob Cardiol Sci Pract 2014; 2014:336-49. [PMID: 25780787 PMCID: PMC4352685 DOI: 10.5339/gcsp.2014.46] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 09/18/2014] [Indexed: 01/06/2023] Open
Abstract
Cardiovascular diseases are the leading cause of death worldwide. Thrombosis, the formation of blood clot (thrombus) in the circulatory system obstructing the blood flow, is one of the main causes behind various ischemic arterial syndromes such as ischemic stroke and myocardial infarction, as well as vein syndromes such as deep vein thrombosis, and consequently, pulmonary emboli. Several thrombolytic agents have been developed for treating thrombosis, the most common being tissue plasminogen activator (tPA), administrated systemically or locally via IV infusion directly proximal to the thrombus, with the aim of restoring and improving the blood flow. TPA triggers the dissolution of thrombi by inducing the conversion of plasminogen to protease plasmin followed by fibrin digestion that eventually leads to clot lysis. Although tPA provides powerful thrombolytic activity, it has many shortcomings, including poor pharmacokinetic profiles, impairment of the reestablishment of normal coronary flow, and impairment of hemostasis, leading to life-threatening bleeding consequences. The bleeding consequence is ascribed to the ability of tPA to circulate throughout the body and therefore can lysis all blood clots in the circulation system, even the good ones that prevent the bleeding and promote injury repair. This review provides an overview of the different delivery approaches for tPA including: liposomes, ultrasound-triggered thrombolysis, anti-fibrin antibody-targeted tPA, camouflaged-tPA, tpA-loaded microcarriers, and nano-modulated delivery approaches.
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Affiliation(s)
- Ibrahim M El-Sherbiny
- Zewail City of Science and Technology, Center for Materials Science, University of Science and Technology, 6th October City, 12588 Giza, Egypt
| | - Islam E Elkholi
- Medical Experimental Research Center, Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | - Magdi H Yacoub
- Harefield Heart Science Centre, National Heart and Lung Institute, Imperial College, London, UK
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Acconcia C, Leung BYC, Manjunath A, Goertz DE. Interactions between individual ultrasound-stimulated microbubbles and fibrin clots. ULTRASOUND IN MEDICINE & BIOLOGY 2014; 40:2134-2150. [PMID: 24882525 DOI: 10.1016/j.ultrasmedbio.2014.03.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2013] [Revised: 02/23/2014] [Accepted: 03/06/2014] [Indexed: 06/03/2023]
Abstract
The use of ultrasound-stimulated microbubbles (USMBs) to promote thrombolysis is well established, but there remains considerable uncertainty about the mechanisms of this process. Here we examine the microscale interactions between individual USMBs and fibrin clots as a function of bubble size, exposure conditions and clot type. Microbubbles (n = 185) were placed adjacent to clot boundaries ("coarse" or "fine") using optical tweezers and exposed to 1-MHz ultrasound as a function of pressure (0.1-0.39 MPa). High-speed (10 kfps) imaging was employed, and clots were subsequently assessed with 2-photon microscopy. For fine clots, 46% of bubbles "embedded" within 10 μm of the clot boundary at pressures of 0.1 and 0.2 MPa, whereas at 0.39 MPa, 53% of bubbles penetrated and transited into the clots with an incidence inversely related to their diameter. A substantial fraction of penetrating bubbles induced fibrin network damage and promoted the uptake of nanobeads. In coarse clots, penetration occurred more readily and at lower pressures than in fine clots. The results therefore provide direct evidence of therapeutically relevant effects of USMBs and indicate their dependence on size, exposure conditions and clot properties.
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Affiliation(s)
- Christopher Acconcia
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada; Sunnybrook Research Institute, Toronto, Ontario, Canada.
| | - Ben Y C Leung
- Sunnybrook Research Institute, Toronto, Ontario, Canada
| | | | - David E Goertz
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada; Sunnybrook Research Institute, Toronto, Ontario, Canada
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14
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Kutty S, Wu J, Hammel JM, Abraham JR, Venkataraman J, Abdullah I, Danford DA, Radio SJ, Lof J, Porter TR. Prevention of arteriovenous shunt occlusion using microbubble and ultrasound mediated thromboprophylaxis. J Am Heart Assoc 2014; 3:e000689. [PMID: 24518555 PMCID: PMC3959668 DOI: 10.1161/jaha.113.000689] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background Palliative shunts in congenital heart disease patients are vulnerable to thrombotic occlusion. High mechanical index (MI) impulses from a modified diagnostic ultrasound (US) transducer during a systemic microbubble (MB) infusion have been used to dissolve intravascular thrombi without anticoagulation, and we sought to determine whether this technique could be used prophylactically to reduce thrombus burden and prevent occlusion of surgically placed extracardiac shunts. Methods and Results Heparin‐bonded ePTFE tubular vascular shunts of 4 mm×2.5 cm (Propaten; W.L Gore) were surgically placed in 18 pigs: a right‐sided side‐to‐side arteriovenous (AV, carotid‐jugular) shunt, and a left‐sided arterio‐arterial (AA, carotid‐carotid) interposition shunt in each animal. After shunt implantation, animals were randomly assigned to one of 3 groups. Transcutaneous, weekly 30‐minute treatments (total of 4 treatments) of either guided high MI US+MB (Group 1; n=6) using a 3% MRX‐801 MB infusion, or US alone (Group 2; n=6) were given separately to each shunt. The third group of 6 pigs received no treatments. The shunts were explanted after 4 weeks and analyzed by histopathology to quantify luminal thrombus area (mm2) for the length of each shunt. No pigs received antiplatelet agents or anticoagulants during the treatment period. The median overall thrombus burden in the 3 groups for AV shunts was 5.10 mm2 compared with 4.05 mm2 in AA (P=0.199). Group 1 pigs had significantly less thrombus burden in the AV shunts (median 2.5 mm2) compared with Group 2 (median 5.6 mm2) and Group 3 (median 7.5 mm2) pigs (P=0.006). No difference in thrombus burden was seen between groups for AA shunts. Conclusion Transcutaneous US with intravenous MB is capable of preventing thrombus accumulation in arteriovenous shunts without the need for antiplatelet agents, and may be a method of preventing progressive occlusion of palliative shunts.
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Affiliation(s)
- Shelby Kutty
- Division of Pediatric Cardiology, University of Nebraska College of Medicine/Children's Hospital & Medical Center, Omaha, NE
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15
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de Saint Victor M, Crake C, Coussios CC, Stride E. Properties, characteristics and applications of microbubbles for sonothrombolysis. Expert Opin Drug Deliv 2014; 11:187-209. [DOI: 10.1517/17425247.2014.868434] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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16
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Kutty S, Wu J, Hammel JM, Xie F, Gao S, Drvol LK, Lof J, Radio SJ, Therrien SL, Danford DA, Porter TR. Microbubble mediated thrombus dissolution with diagnostic ultrasound for the treatment of chronic venous thrombi. PLoS One 2012; 7:e51453. [PMID: 23251539 PMCID: PMC3520800 DOI: 10.1371/journal.pone.0051453] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Accepted: 11/01/2012] [Indexed: 11/19/2022] Open
Abstract
Background Central venous catheter (CVC) thrombi result in significant morbidity in children, and currently available treatments are associated with significant risk. We sought to investigate the therapeutic efficacy of microbubble (MB) enhanced sonothrombolysis for aged CVC associated thrombi in vivo. Methods and Results A model of chronic indwelling CVC in the low superior vena cava with thrombus in situ was established after feasibility and safety testing in 7 pigs; and subsequently applied for repeated, sonothrombolytic treatments in 9 pigs (total 24 treatments). Baseline intracardiac echocardiography (ICE, 10.5F, Siemens), fluoroscopy and saline flushing confirmed the absence of any pre-existing CVC thrombus. A thrombus was then allowed to form and age over 24 hours. The created thrombus was localized and measured by ICE, and transthoracic image guided high mechanical index (MI) two-dimensional US treatments (1.1–1.7 MI; iE33, Philips) applied intermittently whenever intravenously infused MBs (3% MRX-801; NuVox) were visualized near the thrombus (n = 10; Group A). Control pigs (n = 10; Group B) received US without MB. All treatments were randomized. Post-treatment thrombus area by ICE planimetry was compared with pre-treatment measurements. Thrombus area measurements before and after treatment were 0.22 and 0.10 cm2 respectively in Group A; compared to 0.24 and 0.21 cm2 in Group B (p = 0.0003). Effectiveness of longer duration US and MB thrombolytic treatments were studied (n = 4), which suggested that near complete thrombus dissolution is possible. No pulmonary emboli, alterations in oxygen saturation, or hemodynamics occurred with either treatment. Conclusions Guided high MI diagnostic US+systemic MB facilitates reduction of aged CVC associated thrombi in vivo. MB enhanced sonothrombolytic therapy may be a non-invasive safe alternative to thrombolytic agents in treating thrombotic CVC occlusions.
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Affiliation(s)
- Shelby Kutty
- Joint Division of Pediatric Cardiology, University of Nebraska College of Medicine/Creighton University, Children’s Hospital and Medical Center, Omaha, Nebraska, United States of America
| | - Juefei Wu
- Department of Internal Medicine, Section of Cardiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - James M. Hammel
- Division of Cardiovascular Surgery, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Feng Xie
- Department of Internal Medicine, Section of Cardiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Shunji Gao
- Department of Internal Medicine, Section of Cardiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Lucas K. Drvol
- Department of Internal Medicine, Section of Cardiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - John Lof
- Department of Internal Medicine, Section of Cardiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Stanley J. Radio
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Stacey L. Therrien
- Department of Internal Medicine, Section of Cardiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - David A. Danford
- Joint Division of Pediatric Cardiology, University of Nebraska College of Medicine/Creighton University, Children’s Hospital and Medical Center, Omaha, Nebraska, United States of America
| | - Thomas R. Porter
- Department of Internal Medicine, Section of Cardiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- * E-mail:
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Bader KB, Holland CK. Gauging the likelihood of stable cavitation from ultrasound contrast agents. Phys Med Biol 2012; 58:127-44. [PMID: 23221109 DOI: 10.1088/0031-9155/58/1/127] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The mechanical index (MI) was formulated to gauge the likelihood of adverse bioeffects from inertial cavitation. However, the MI formulation did not consider bubble activity from stable cavitation. This type of bubble activity can be readily nucleated from ultrasound contrast agents (UCAs) and has the potential to promote beneficial bioeffects. Here, the presence of stable cavitation is determined numerically by tracking the onset of subharmonic oscillations within a population of bubbles for frequencies up to 7 MHz and peak rarefactional pressures up to 3 MPa. In addition, the acoustic pressure rupture threshold of an UCA population was determined using the Marmottant model. The threshold for subharmonic emissions of optimally sized bubbles was found to be lower than the inertial cavitation threshold for all frequencies studied. The rupture thresholds of optimally sized UCAs were found to be lower than the threshold for subharmonic emissions for either single cycle or steady state acoustic excitations. Because the thresholds of both subharmonic emissions and UCA rupture are linearly dependent on frequency, an index of the form I(CAV) = P(r)/f (where P(r) is the peak rarefactional pressure in MPa and f is the frequency in MHz) was derived to gauge the likelihood of subharmonic emissions due to stable cavitation activity nucleated from UCAs.
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Affiliation(s)
- Kenneth B Bader
- Department of Internal Medicine, Division of Cardiovascular Diseases, University of Cincinnati, Cincinnati, OH, USA.
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Abstract
OBJECTIVES To characterize the ability of high-intensity focused ultrasound to achieve thrombolysis in vitro and investigate the feasibility of this approach as a means of restoring blood flow in thrombus-occluded arteries in vivo. MATERIALS AND METHODS All experiments were approved by the Institutional Animal Care Committee. Thrombolysis was performed with a 1.51-MHz focused ultrasound transducer with pulse lengths of 0.1 to 10 milliseconds and acoustic powers up to 300 W. In vitro experiments were performed with blood clots formed from rabbit arterial blood and situated in 2-mm diameter tubing. Both single location and flow bypass recanalization experiments were conducted. In vitro clot erosion was assessed with 30-MHz ultrasound, with debris size measured with filters and a Coulter counter. In vivo clots were initiated in the femoral arteries of rabbits (n = 26). Cavitation signals from bubbles formed during exposure were monitored. In vivo flow restoration was assessed with 23-MHz Doppler ultrasound. RESULTS At a single location, in vitro clot erosion volumes increased with exposure power and pulse length, with debris size reducing with increasing pulse length. Flow bypass experiments achieved 99.2% clot erosion with 1.1% of debris above 0.5 mm in size. In vivo, 10 milliseconds pulses were associated with bleeding, but at 1 millisecond, it was feasible to achieve partial flow restoration in 6 of the 10 clots with only 1 of the 10 showing evidence of bleeding. In all cases, thrombolysis occurred only in the presence of cavitation. CONCLUSION High-intensity focused ultrasound thrombolysis is feasible as a means of restoring partial blood flow in thrombus-occluded arteries in the absence of thrombolytic agents. The potential for bleeding with this approach requires further investigation.
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Meairs S, Alonso A, Hennerici MG. Progress in Sonothrombolysis for the Treatment of Stroke. Stroke 2012; 43:1706-10. [DOI: 10.1161/strokeaha.111.636332] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Stephen Meairs
- From the Department of Neurology, Universitätsmedizin Mannheim, University of Heidelberg, Mannheim, Germany
| | - Angelika Alonso
- From the Department of Neurology, Universitätsmedizin Mannheim, University of Heidelberg, Mannheim, Germany
| | - Michael G. Hennerici
- From the Department of Neurology, Universitätsmedizin Mannheim, University of Heidelberg, Mannheim, Germany
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Borrelli MJ, O'Brien WD, Bernock LJ, Williams HR, Hamilton E, Wu J, Oelze ML, Culp WC. Production of uniformly sized serum albumin and dextrose microbubbles. ULTRASONICS SONOCHEMISTRY 2012; 19:198-208. [PMID: 21689961 PMCID: PMC3152625 DOI: 10.1016/j.ultsonch.2011.05.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Revised: 03/21/2011] [Accepted: 05/15/2011] [Indexed: 05/05/2023]
Abstract
Uniformly-sized preparations with average microbubble (MB) diameters from 1 to 7 μm were produced reliably by sonicating decafluorobutane-saturated solutions of serum albumin and dextrose. Detailed protocols for producing and size-separating the MBs are presented, along with the effects that changing each production parameter (serum albumin concentration, sonication power, sonication time, etc.) had on MB size distribution and acoustic stability. These protocols can be used to produce MBs for experimental applications or serve as templates for developing new protocols that yield MBs with physical and acoustic properties better suited to specific applications. Size stability and ultrasonic performance quality control tests were developed to assure that successive MB preparations perform identically and to distinguish the physical and acoustic properties of identically sized MBs produced with different serum albumin-dextrose formulations and sonication parameters. MBs can be stored at 5 °C for protracted periods (2 weeks to one year depending on formulation).
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Affiliation(s)
- Michael J Borrelli
- Department of Radiology, University of Arkansas for Medical Sciences, 4301 West Markham Street Slot #556, Little Rock, AR 72205, USA.
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Amaral-Silva A, Piñeiro S, Molina CA. Sonothrombolysis for the treatment of acute stroke: current concepts and future directions. Expert Rev Neurother 2011; 11:265-73. [PMID: 21306213 DOI: 10.1586/ern.11.3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Achieving rapid reperfusion transcranial color-coded duplex is the critical issue in acute stroke treatment. Ultrasound (US) generates negative pressure waves that are associated with an increase in either intrinsic or intravenous tissue plasminogen activator (tPA)-induced fibrinolytic activity. Higher rates of tPA-induced arterial recanalization, associated with a trend towards better functional outcome, have been safely achieved by using high-frequency US. By contrast, the use of low-frequency US and transcranial color-coded duplex has been linked to significant hemorrhagic complications. US-accelerated thrombolysis has been safely enhanced by lowering the amount of energy needed for acoustic cavitation with the administration of microbubbles. Other applications of US are being studied, including its intra-arterial use. Operator-independent devices, which will spread the use of these US techniques further, are also being developed. This article reviews the present status of sonothrombolysis in acute stroke treatment, highlighting both experimental and clinical studies addressing this issue, and discusses its future regarding both efficacy and safety.
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Affiliation(s)
- Alexandre Amaral-Silva
- Cerebrovascular Unit, Hospital de São José, Centro Hospitalar de Lisboa Central, Lisbon, Portugal
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Flores R, Hennings LJ, Lowery JD, Brown AT, Culp WC. Microbubble-augmented ultrasound sonothrombolysis decreases intracranial hemorrhage in a rabbit model of acute ischemic stroke. Invest Radiol 2011; 46:419-24. [PMID: 21343824 PMCID: PMC3109116 DOI: 10.1097/rli.0b013e31820e143a] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Increasing evidence confirms that microbubble (MB)-augmented ultrasound (US) thrombolysis enhances clot lysis with or without tissue plasminogen activator (tPA). Intracranial hemorrhage (ICH) is a major complication militating against tPA use in acute ischemic stroke. We quantified the incidence of ICH associated with tPA thrombolysis and MB + US therapy and compared infarct volumes in a rabbit model of acute ischemic stroke. MATERIALS AND METHODS Rabbits (n = 158) received a 1.0-mm clot, angiographically injected into the internal carotid artery causing infarcts. Rabbits were randomized to 6 test groups including (1) control (n = 50), embolized without therapy, (2) US (n = 18), (3) tPA only (n = 27), (4) tPA + US (n = 22), (5) MB + US (n = 27), and (6) tPA + MB + US (n = 14). US groups received pulsed wave US (1 MHz, 0.8 W/cm) for 1 hour; rabbits with tPA received intravenous tPA (0.9 mg/kg) over 1 hour. Rabbits with MB received intravenous MB (0.16 mg/kg) given over 30 minutes. Rabbits were killed 24 hours later and infarct volume and incidence, location, and severity of ICH were determined by histology and pathologic examination. RESULTS Percentage of rabbits having ICH outside the infarct area was significantly decreased (P = 0.004) for MB + US (19%) rabbits compared with tPA + US (73%), US only (56%), tPA (48%), tPA + MB + US (36%), and control (36%) rabbits. Incidence and severity of ICH within the infarct did not differ (P > 0.39). Infarct volume was significantly greater (P = 0.002) for rabbits receiving US (0.97% ± 0.17%) than for MB + US (0.20% ± 0.14%), tPA + US (0.15% ± 0.16%), tPA (0.14% ± 0.14%), and tPA + MB + US (0.10% ± 20%) rabbits; these treatments collectively, excluding US only, differed (P = 0.03) from control (0.45% ± 0.10%). CONCLUSIONS Treatment with MB + US after embolization decreased the incidence of ICH and efficacy was similar to tPA in reducing infarct volume.
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Affiliation(s)
- Rene Flores
- Department of Radiology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Leah J. Hennings
- Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - John D. Lowery
- Division of Lab Animal Medicine, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Aliza T. Brown
- Department of Radiology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - William C. Culp
- Department of Radiology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
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Xie F, Everbach EC, Gao S, Drvol LK, Shi WT, Vignon F, Powers JE, Lof J, Porter TR. Effects of attenuation and thrombus age on the success of ultrasound and microbubble-mediated thrombus dissolution. ULTRASOUND IN MEDICINE & BIOLOGY 2011; 37:280-8. [PMID: 21208727 PMCID: PMC3059129 DOI: 10.1016/j.ultrasmedbio.2010.10.022] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Revised: 09/17/2010] [Accepted: 10/20/2010] [Indexed: 05/09/2023]
Abstract
The purpose of this study was to examine the effects of applied mechanical index, incident angle, attenuation and thrombus age on the ability of 2-D vs. 3-D diagnostic ultrasound and microbubbles to dissolve thrombi. A total of 180 occlusive porcine arterial thrombi of varying age (3 or 6 h) were examined in a flow system. A tissue-mimicking phantom of varying thickness (5 to 10 cm) was placed over the thrombosed vessel and the 2-D or 3-D diagnostic transducer aligned with the thrombosed vessel using a positioning system. Diluted lipid-encapsulated microbubbles were infused during ultrasound application. Percent thrombus dissolution (%TD) was calculated by comparison of clot mass before and after treatment. Both 2-D and 3-D-guided ultrasound increased %TD compared with microbubbles alone, but %TD achieved with 6-h-old thrombi was significantly less than 3-h-old thrombi. Thrombus dissolution was achieved at 10 cm tissue-mimicking depths, even without inertial cavitation. In conclusion, diagnostic 2-D or 3-D ultrasound can dissolve thrombi with intravenous nontargeted microbubbles, even at tissue attenuation distances of up to 10 cm. This treatment modality is less effective, however, for older aged thrombi.
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Affiliation(s)
- Feng Xie
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198-2265, USA.
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24
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Meairs S, Hennerici M, Mohr J. Ultrasonography. Stroke 2011. [DOI: 10.1016/b978-1-4160-5478-8.10044-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Kutty S, Xie F, Gao S, Drvol LK, Lof J, Fletcher SE, Radio SJ, Danford DA, Hammel JM, Porter TR. Sonothrombolysis of intra-catheter aged venous thrombi using microbubble enhancement and guided three-dimensional ultrasound pulses. J Am Soc Echocardiogr 2010; 23:1001-6. [PMID: 20696549 DOI: 10.1016/j.echo.2010.06.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2010] [Indexed: 10/19/2022]
Abstract
BACKGROUND Central venous and arterial catheters are a major source of thromboembolic disease in children. The investigators hypothesized that guided high-mechanical index (MI) impulses from diagnostic three-dimensional (3D) ultrasound during an intravenous microbubble infusion could dissolve these thrombi. METHODS An in vitro system simulating intracatheter thrombi was created and then treated with guided high-MI impulses from 3D ultrasound, using low-MI microbubble sensitive imaging pulse sequence schemes to detect the microbubbles. Ten aged thrombi >24 hours old were tested using 3D ultrasound coupled with a continuous diluted microbubble infusion (group A) and 10 with 3D ultrasound alone (group B). RESULTS The mean thrombus age was 28.6 hours (range, 26.6-30.3 hours). Group A exhibited a 55 +/- 19% reduction in venous thrombus size compared with 31 +/- 10% in group B (P = .008). Feasibility testing was performed in four pigs, establishing an in vivo model to investigate further the efficacy of this approach. CONCLUSIONS Sonothrombolysis of aged intracatheter venous thrombi can be achieved with commercially available microbubbles and guided high-MI ultrasound from a diagnostic 3D transducer.
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Affiliation(s)
- Shelby Kutty
- Joint Division of Pediatric Cardiology, University of Nebraska, Children's Hospital and Medical Center, Omaha, Nebraska 68196, USA
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Medel R, Crowley RW, McKisic MS, Dumont AS, Kassell NF. Sonothrombolysis: an emerging modality for the management of stroke. Neurosurgery 2009; 65:979-93; discussion 993. [PMID: 19834413 DOI: 10.1227/01.neu.0000350226.30382.98] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE Ischemic stroke and intracranial hemorrhage remain a persistent scourge in Western civilization. Therefore, novel therapeutic modalities are desperately needed to expand the current limitations of treatment. Sonothrombolysis possesses the potential to fill this void because it has experienced a dramatic evolution from the time of early conceptualization in the 1960s. This process began in the realm of peripheral and cardiovascular disease and has since progressed to encompass intracranial pathologies. Our purpose is to provide a comprehensive review of the historical progression and existing state of knowledge, including underlying mechanisms as well as evidence for clinical application of ultrasound thrombolysis. METHODS Using MEDLINE, in addition to cross-referencing existing publications, a meticulous appraisal of the literature was conducted. Additionally, personal communications were used as appropriate. RESULTS This appraisal revealed several different technologies close to broad clinical use. However, fundamental questions remain, especially in regard to transcranial high-intensity focused ultrasound. Currently, the evidence supporting low intensity ultrasound's potential in isolation, without tissue plasminogen, remains uncertain; however, possibilities exist in the form of microbubbles to allow for focal augmentation with minimal systemic consequences. Alternatively, the literature clearly demonstrates, the efficacy of high-intensity focused ultrasound for independent thrombolysis. CONCLUSION Sonothrombolysis exists as a promising modality for the noninvasive or minimally invasive management of stroke, both ischemic and hemorrhagic. Further research facilitating clinical application is warranted.
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Affiliation(s)
- Ricky Medel
- Department of Neurological Surgery, University of Virginia School of Medicine, Charlottesville, Virginia, USA
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Chen SC, Ruan JL, Cheng PW, Chuang YH, Li PC. In vitro evaluation of ultrasound-assisted thrombolysis using a targeted ultrasound contrast agent. ULTRASONIC IMAGING 2009; 31:235-246. [PMID: 20458876 DOI: 10.1177/016173460903100402] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A thrombus-targeted ultrasound contrast agent bound with tirofiban - a glycoprotein (GP) IIb/IIIa antagonist that can specifically bind to activated platelets in the thrombus - was designed to enhance both the image contrast and thrombolysis effect. In this study, we used 76 canine thrombi for investigation. The targeting ability to thrombi was confirmed by microphotography and high-frequency ultrasound (40 MHz) imaging. The effect of the targeted microbubbles on thrombolysis enhancement was investigated using an in vitro flow system: targeted and nontargeted microbubbles flowed through the clot for 30 seconds with a washing step; the microbubbles remained on the clot that were then cavitated by ultrasound (frequency = 1 MHz, MI = 1.2). The extent of thrombolysis was evaluated by weight reduction and histology analysis. The targeted microbubbles reduced the weight of thrombi by a factor of 1.7 times that of the nontargeted microbubbles. (clot weight reduction: 23.1 +/- 5.3% versus 13.6 +/- 4.9%, p < 0.01 between targeted and nontargeted group), and the signal enhancement was 3.34 +/- 0.30 dB (mean +/- SD, p < 0.01 compared to control). We conclude that targeted microbubbles are applicable not only for molecular imaging of thrombi but also for improving the effectiveness of ultrasound-assisted thrombolysis.
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Affiliation(s)
- Szu-Chia Chen
- Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan
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28
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Molina CA, Barreto AD, Tsivgoulis G, Sierzenski P, Malkoff MD, Rubiera M, Gonzales N, Mikulik R, Pate G, Ostrem J, Singleton W, Manvelian G, Unger EC, Grotta JC, Schellinger PD, Alexandrov AV. Transcranial ultrasound in clinical sonothrombolysis (TUCSON) trial. Ann Neurol 2009; 66:28-38. [PMID: 19670432 DOI: 10.1002/ana.21723] [Citation(s) in RCA: 190] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVE Microspheres (microS) reach intracranial occlusions and transmit energy momentum from an ultrasound wave to residual flow to promote recanalization. We report a randomized multicenter phase II trial of microS dose escalation with systemic thrombolysis. METHODS Stroke patients receiving 0.9mg/kg tissue plasminogen activator (tPA) with pretreatment proximal intracranial occlusions on transcranial Doppler (TCD) were randomized (2:1 ratio) to microS (MRX-801) infusion over 90 minutes (Cohort 1, 1.4ml; Cohort 2, 2.8ml) with continuous TCD insonation, whereas controls received tPA and brief TCD assessments. The primary endpoint was symptomatic intracerebral hemorrhage (sICH) within 36 hours after tPA. RESULTS Among 35 patients (Cohort 1 = 12, Cohort 2 = 11, controls = 12) no sICH occurred in Cohort 1 and controls, whereas 3 (27%, 2 fatal) sICHs occurred in Cohort 2 (p = 0.028). Sustained complete recanalization/clinical recovery rates (end of TCD monitoring/3 month) were 67%/75% for Cohort 1, 46%/50% for Cohort 2, and 33%/36% for controls (p = 0.255/0.167). The median time to any recanalization tended to be shorter in Cohort 1 (30 min; interquartile range [IQR], 6) and Cohort 2 (30 min; IQR, 69) compared to controls (60 min; IQR, 5; p = 0.054). Although patients with sICH had similar screening and pretreatment systolic blood pressure (SBP) levels in comparison to the rest, higher SBP levels were documented in sICH+ patients at 30 minutes, 60 minutes, 90 minutes, and 24-36 hours following tPA bolus. INTERPRETATION Perflutren lipid microS can be safely combined with systemic tPA and ultrasound at a dose of 1.4ml. Safety concerns in the second dose tier may necessitate extended enrollment and further experiments to determine the mechanisms by which microspheres interact with tissues. In both dose tiers, sonothrombolysis with microS and tPA shows a trend toward higher early recanalization and clinical recovery rates compared to standard intravenous tPA therapy. Ann Neurol 2009;66:28-38.
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Affiliation(s)
- Carlos A Molina
- Neurovascular Unit, Department of Neurology, Hospital Vall d'Hebron, Barcelona, Spain
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Barreto AD, Sharma VK, Lao AY, Schellinger PD, Amarenco P, Sierzenski P, Alexandrov AV, Molina CA. Safety and dose-escalation study design of Transcranial Ultrasound in Clinical SONolysis for acute ischemic stroke: the TUCSON Trial. Int J Stroke 2009; 4:42-8. [PMID: 19236498 DOI: 10.1111/j.1747-4949.2009.00252.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Rationale Transcranial Doppler (TCD) monitoring during intravenous tissue plasminogen activator (i.v.-tPA) infusion increases recanalization rates in acute ischemic stroke. Addition of perflutren-lipid microspheres MRX-801 (microS) may further enhance the process of recanalization. This article describes the design of the Transcranial Ultrasound in Clinical SONolysis (TUCSON) trial. Aims and Design TUCSON is a phase I-II, randomized, placebo-controlled, open-label, safety, dose-escalation clinical trial of microS+TCD ultrasound (sonolysis). Patients with acute ischemic stroke and arterial intracranial occlusions are enrolled within 3 h of symptom onset. All patients receive standard i.v.-tPA and will be randomized to 90 min of continuous 2-MHz TCD+microS or 90 min of saline+brief TCD vessel assessments. The safety profile of four escalating dose tiers will be assessed. Arterial occlusions and recanalization are defined with the Thrombolysis in Brain Ischemia flow grades. Study Outcomes Safety is determined by the rates of symptomatic intracerebral hemorrhage within 36 h. Neurological deficits and outcomes are measured with the National Institute of Health Stroke Scale and modified Rankin Scale (mRS). The signal-of-efficacy is determined by rates of recanalization, dramatic or early clinical recovery within 2 h, clinical recovery at 24-36 h and independent outcome (mRS 0-2) at 90 days.
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Affiliation(s)
- Andrew D Barreto
- Department of Neurology, University of Texas-Houston Stroke Team, Houston, TX, USA
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Xie F, Lof J, Matsunaga T, Zutshi R, Porter TR. Diagnostic ultrasound combined with glycoprotein IIb/IIIa-targeted microbubbles improves microvascular recovery after acute coronary thrombotic occlusions. Circulation 2009; 119:1378-85. [PMID: 19255341 DOI: 10.1161/circulationaha.108.825067] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND The high mechanical index (MI) impulses from a diagnostic ultrasound transducer may be a method of recanalizing acutely thrombosed vessels if the impulses are applied only when microbubbles are channeling through the thrombus. METHODS AND RESULTS In 45 pigs with acute left anterior descending thrombotic occlusions, a low-MI pulse sequence scheme (contrast pulse sequencing) was used to image the myocardium and guide the delivery of high-MI (1.9 MI) impulses during infusion of either intravenous platelet-targeted microbubbles or nontargeted microbubbles. A third group received no diagnostic ultrasound and microbubbles. All groups received half-dose recombinant prourokinase, heparin, and aspirin. Contrast pulse sequencing examined replenishment of contrast within the central portion of the risk area and guided the application of high-MI impulses. Angiographic recanalization rates, resolution of ST-segment elevation on ECG, and wall thickening were analyzed. Pigs receiving platelet-targeted microbubbles had more rapid replenishment of the central portion of the risk area (80% versus 40% for nontargeted microbubbles; P=0.03) and higher epicardial recanalization rates (53% versus 7% for prourokinase alone; P=0.01). Replenishment of contrast within the risk area (whether with platelet-targeted microbubbles or nontargeted microbubbles) was associated with both higher recanalization rates and even higher rates of ST-segment resolution (82% versus 21% for prourokinase alone; P=0.006). ST-segment resolution occurred in 6 pigs (40%) treated with microbubbles who did not have epicardial recanalization, of which 5 had recovery of wall thickening. CONCLUSIONS Intravenous platelet-targeted microbubbles combined with brief high-MI diagnostic ultrasound impulses guided by contrast pulse sequencing improve both epicardial recanalization rates and microvascular recovery.
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Affiliation(s)
- Feng Xie
- Department of Internal Medicine, Section of Cardiology, University of Nebraska Medical Center, Omaha, NE 68198-2265, USA.
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Fatar M, Stroick M, Griebe M, Alonso A, Kreisel S, Kern R, Hennerici M, Meairs S. Effect of combined ultrasound and microbubbles treatment in an experimental model of cerebral ischemia. ULTRASOUND IN MEDICINE & BIOLOGY 2008; 34:1414-1420. [PMID: 18436368 DOI: 10.1016/j.ultrasmedbio.2008.02.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2007] [Revised: 12/18/2007] [Accepted: 02/09/2008] [Indexed: 05/26/2023]
Abstract
Combined 2-MHz ultrasound (US) and second-generation, sulfur hexafluoride microbubbles (MB) treatment (US+MB) was performed in a permanent middle cerebral artery (MCA) occlusion model in rats to evaluate possible effects on the ischemic cascade. We used 16 Wistar rats and the MCA occlusion model for stroke induction. Glutamate, pyruvate, lactate and glycerol levels were measured by intracerebral microdialysis before and after stroke induction and after US+MB application (n = 8) for 20 h. After 24 h, brain infarct volume, apoptosis and IL-6 and TNF-alpha levels were evaluated. The infarct volume was significantly reduced (p < 0.05) in the US+MB-treated group compared with control animals. In additional, glutamate levels were significantly lower in US+MB-treated animals, and these animals showed a higher rate of apoptotic cell death in the infarcted area. The levels of IL-6 and TNF-alpha concentrations were not different in both groups, and there was no apoptotic cell death outside the infarction in animals treated with US+MB. The results demonstrate that US+MB with second generation microbubbles does not have a harmful effect on ischemic stroke in an MCA occlusion model of the rat.
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Affiliation(s)
- M Fatar
- Department of Neurology, Universitätsklinikum Mannheim, University of Heidelberg, Heidelberg, Germany.
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Datta S, Coussios CC, Ammi AY, Mast TD, de Courten-Myers GM, Holland CK. Ultrasound-enhanced thrombolysis using Definity as a cavitation nucleation agent. ULTRASOUND IN MEDICINE & BIOLOGY 2008; 34:1421-33. [PMID: 18378380 PMCID: PMC2945910 DOI: 10.1016/j.ultrasmedbio.2008.01.016] [Citation(s) in RCA: 173] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Ultrasound has been shown previously to act synergistically with a thrombolytic agent, such as recombinant tissue plasminogen activator (rt-PA) to accelerate thrombolysis. In this in vitro study, a commercial contrast agent, Definity, was used to promote and sustain the nucleation of cavitation during pulsed ultrasound exposure at 120 kHz. Ultraharmonic signals, broadband emissions and harmonics of the fundamental were measured acoustically by using a focused hydrophone as a passive cavitation detector and used to quantify the level of cavitation activity. Human whole blood clots suspended in human plasma were exposed to a combination of rt-PA, Definity and ultrasound at a range of ultrasound peak-to-peak pressure amplitudes, which were selected to expose clots to various degrees of cavitation activity. Thrombolytic efficacy was determined by measuring clot mass loss before and after the treatment and correlated with the degree of cavitation activity. The penetration depth of rt-PA and plasminogen was also evaluated in the presence of cavitating microbubbles using a dual-antibody fluorescence imaging technique. The largest mass loss (26.2%) was observed for clots treated with 120-kHz ultrasound (0.32-MPa peak-to-peak pressure amplitude), rt-PA and stable cavitation nucleated by Definity. A significant correlation was observed between mass loss and ultraharmonic signals (r = 0.85, p < 0.0001, n = 24). The largest mean penetration depth of rt-PA (222 microm) and plasminogen (241 microm) was observed in the presence of stable cavitation activity. Stable cavitation activity plays an important role in enhancement of thrombolysis and can be monitored to evaluate the efficacy of thrombolytic treatment.
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Affiliation(s)
- Saurabh Datta
- Dept. of Biomedical Engineering, University of Cincinnati, Cincinnati, Ohio, USA
| | | | - Azzdine Y Ammi
- Dept. of Biomedical Engineering, University of Cincinnati, Cincinnati, Ohio, USA
| | - T. Douglas Mast
- Dept. of Biomedical Engineering, University of Cincinnati, Cincinnati, Ohio, USA
| | | | - Christy K. Holland
- Dept. of Biomedical Engineering, University of Cincinnati, Cincinnati, Ohio, USA
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Sassaroli E, Hynynen K. Cavitation threshold of microbubbles in gel tunnels by focused ultrasound. ULTRASOUND IN MEDICINE & BIOLOGY 2007; 33:1651-60. [PMID: 17590501 PMCID: PMC2078601 DOI: 10.1016/j.ultrasmedbio.2007.04.018] [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] [Received: 08/26/2006] [Revised: 04/20/2007] [Accepted: 04/26/2007] [Indexed: 05/11/2023]
Abstract
The investigation of inertial cavitation in micro-tunnels has significant implications for the development of therapeutic applications of ultrasound such as ultrasound-mediated drug and gene delivery. The threshold for inertial cavitation was investigated using a passive cavitation detector with a center frequency of 1 MHz. Micro-tunnels of various diameters (90 to 800 microm) embedded in gel were fabricated and injected with a solution of Optison(trade mark) contrast agent of concentrations 1.2% and 0.2% diluted in water. An ultrasound pulse of duration 500 ms and center frequency 1.736 MHz was used to insonate the microbubbles. The acoustic pressure was increased at 1-s intervals until broadband noise emission was detected. The pressure threshold at which broadband noise emission was observed was found to be dependent on the diameter of the micro-tunnels, with an average increase of 1.2 to 1.5 between the smallest and the largest tunnels, depending on the microbubble concentration. The evaluation of inertial cavitation in gel tunnels rather than tubes provides a novel opportunity to investigate microbubble collapse in a situation that simulates in vivo blood vessels better than tubes with solid walls do.
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Affiliation(s)
- Elisabetta Sassaroli
- Department of Radiology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.
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34
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Coussios CC, Farny CH, Haar GT, Roy RA. Role of acoustic cavitation in the delivery and monitoring of cancer treatment by high-intensity focused ultrasound (HIFU). Int J Hyperthermia 2007; 23:105-20. [PMID: 17578336 DOI: 10.1080/02656730701194131] [Citation(s) in RCA: 243] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Acoustic cavitation has been shown to play a key role in a wide array of novel therapeutic ultrasound applications. This paper presents a brief discussion of the physics of thermally relevant acoustic cavitation in the context of high-intensity focussed ultrasound (HIFU). Models for how different types of cavitation activity can serve to accelerate tissue heating are presented, and results suggest that the bulk of the enhanced heating effect can be attributed to the absorption of broadband acoustic emissions generated by inertial cavitation. Such emissions can be readily monitored using a passive cavitation detection (PCD) scheme and could provide a means for real-time treatment monitoring. It is also shown that the appearance of hyperechoic regions (or bright-ups) on B-mode ultrasound images constitutes neither a necessary nor a sufficient condition for inertial cavitation activity to have occurred during HIFU exposure. Once instigated at relatively large HIFU excitation amplitudes, bubble activity tends to grow unstable and to migrate toward the source transducer, causing potentially undesirable pre-focal damage. Potential means of controlling inertial cavitation activity using pulsed excitation so as to confine it to the focal region are presented, with the intention of harnessing cavitation-enhanced heating for optimal HIFU treatment delivery. The role of temperature elevation in mitigating bubble-enhanced heating effects is also discussed, along with other bubble-field effects such as multiple scattering and shielding.
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Affiliation(s)
- C C Coussios
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, UK.
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Tsutsui JM, Xie F, Johanning J, Lof J, Cory B, He A, Thomas L, Matsunaga T, Unger E, Porter TR. Treatment of deeply located acute intravascular thrombi with therapeutic ultrasound guided by diagnostic ultrasound and intravenous microbubbles. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2006; 25:1161-8. [PMID: 16929017 DOI: 10.7863/jum.2006.25.9.1161] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
OBJECTIVE We sought to determine the added value of simultaneous imaging of intravenously infused microbubbles that are being used to dissolve an intravascular thrombus with therapeutic ultrasound (TUS). METHODS In a chronic canine arteriovenous graft occluded by a thrombus, TUS (1 MHz) was applied through a 6-cm-thick tissue-mimicking phantom (measured mean +/- SD peak negative pressure through the phantom, 958 +/- 104 kPa) during an intravenous infusion of either saline (n = 6 occlusions) or lipid-encapsulated microbubbles (ImaRx Therapeutics, Inc, Tucson, AZ). Therapeutic ultrasound was intermittently applied during the microbubble infusion either at set time intervals (n = 6 occlusions) or when simultaneous diagnostic ultrasound (DUS) indicated a sustained presence of microbubbles (n = 12 occlusions). Success was defined as return of rapid flow within the graft (grade 3 flow). RESULTS Diagnostic ultrasound showed microbubbles moving through small channels within the thrombus before angiographic evidence of flow in the graft. This guided the timing of TUS application better than using set time intervals. Angiographic clearance of the thrombus and restoration of grade 3 flow at 45 minutes of treatment were seen in 33% of deeply located thrombosed grafts treated with TUS at set time intervals and 92% of grafts treated with TUS guided by DUS (P < .001 compared with set time intervals). CONCLUSIONS The use of TUS with intravenous microbubbles has a high success rate in recanalizing deeply located thrombosed arteriovenous grafts when performed with DUS guidance.
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Affiliation(s)
- Jeane M Tsutsui
- Department of Internal Medicine, Section of Cardiology, University of Nebraska Medical Center, 981165 Nebraska Medical Center, Omaha, 68198-1165 USA
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36
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Tsutsui JM, Kusler M, Porter TR. Intravenous myocardial contrast echocardiography for the diagnosis of coronary artery disease. Curr Opin Cardiol 2005; 20:381-5. [PMID: 16093756 DOI: 10.1097/01.hco.0000176404.48496.a2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW Myocardial contrast echocardiography is a recently developed technique that permits the noninvasive assessment of myocardial perfusion. Myocardial contrast enhancement from microbubbles characteristically reflects the myocardial blood volume. The analysis of microbubble kinetics using quantitative myocardial contrast echocardiography permits the evaluation of myocardial blood flow both at rest and during pharmacological stress. RECENT FINDINGS Myocardial contrast echocardiography has been shown to have good concordance with single photon emission computed tomography for the localization of perfusion abnormalities. As a result of its better spatial resolution and the fact that it tracks myocardial blood flow changes, it seems to have higher sensitivity for the detection of angiographically significant coronary artery disease, while maintaining similar specificity to single photon emission computed tomography. Low mechanical index imaging techniques (real-time myocardial contrast echocardiography) have the advantage of permitting simultaneous analysis of wall motion and perfusion, which is particularly important during dobutamine stress. Myocardial perfusion analysis using real-time myocardial contrast echocardiography has been shown to have higher sensitivity and diagnostic accuracy than wall motion analysis for the detection of coronary artery disease. Quantitative myocardial contrast echocardiography seems to overcome the expertise requirements for appropriate interpretation of myocardial perfusion images, and may have been demonstrated to be an accurate supplemental technique for estimating the severity of coronary artery disease. SUMMARY Recent technological advances have positioned myocardial contrast echocardiography as a safe and feasible technique for the evaluation of myocardial perfusion. The analysis of myocardial perfusion using myocardial contrast echocardiography has higher diagnostic accuracy than wall motion analysis for detecting coronary artery disease.
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Affiliation(s)
- Jeane M Tsutsui
- Department of Internal Medicine, Section of Cardiology, University of Nebraska Medical Center, Omaha, Nebraska 68198-1165, USA
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37
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Viguier A, Petit R, Rigal M, Cintas P, Larrue V. Continuous monitoring of middle cerebral artery recanalization with transcranial color-coded sonography and Levovist. J Thromb Thrombolysis 2005; 19:55-9. [PMID: 15976968 DOI: 10.1007/s11239-005-0940-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
BACKGROUND AND PURPOSE Treatment of acute ischemic stroke with intravenous recombinant tissue plasminogen activator (rtPA) is relatively ineffective in patients with large vessel occlusion. Numerous experimental studies have demonstrated that ultrasound (US) can accelerate enzymatic fibrinolysis and acceleration of lysis by US is enhanced in the presence of microbubbles used as echo-contrast agents. The purpose of this study was to evaluate the feasibility of continuous monitoring of middle cerebral artery (MCA) recanalization using transcranial color-coded sonography (TCCS) and intravenously administered microbubbles. METHODS Recanalization of middle cerebral artery (MCA) mainstem occlusion was assessed using continuous monitoring with TCCS and intravenously administered galactose-based microbubbles (Levovist) in 8 consecutive patients with acute ischemic stroke treated with intravenous rt-PA within 3 hours of symptom onset. RESULTS Recanalization at one hour occurred in 4 of 8 patients. The median NIHSS score was 21 (range 10 to 28) at baseline, 15 (range 0 to 24) at 1 h, and 11 (range 0 to 22) at 24 h. Asymptomatic hemorrhagic transformation (HT) was demonstrated on brain imaging in 6 patients. CONCLUSION This study demonstrates the feasibility of continuous monitoring of MCA recanalization using TCCS and Levovist, in acute stroke patients. The findings suggest a high rate of asymptomatic HT in monitored patients. Although all HTs were asymptomatic and did not preclude early clinical improvement, particular attention should be given to the incidence and clinical significance of HT in future studies using these methods.
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Affiliation(s)
- Alain Viguier
- Department of Neurology, University of Toulouse, Hôpital de Rangueil, 1 Avenue Jean-Poulhes, EA 2049 Toulouse Cedex 9, France.
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38
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Xie F, Tsutsui JM, Lof J, Unger EC, Johanning J, Culp WC, Matsunaga T, Porter TR. Effectiveness of lipid microbubbles and ultrasound in declotting thrombosis. ULTRASOUND IN MEDICINE & BIOLOGY 2005; 31:979-85. [PMID: 15972204 DOI: 10.1016/j.ultrasmedbio.2005.03.008] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2004] [Revised: 03/12/2005] [Accepted: 03/17/2005] [Indexed: 05/03/2023]
Abstract
The objectives of this study were to determine the effectiveness of lipid-encapsulated microbubbles and ultrasound (US) in recanalizing arteriovenous graft thrombi and the effect that tissue attenuation has on the success rate. A total of 55 thrombotic occlusions were created in four canines. The thrombosed grafts were randomly treated with two different 1-MHz US intensities, low (0.4 to 0.6 W/cm(2)) and high (10 W/cm(2)). Intragraft microbubbles were compared with intragraft saline and with the same dose of microbubbles given IV. IV microbubbles were also given both in the presence and absence of a tissue-mimicking phantom. High-intensity US (10 W/cm(2)) with intragraft microbubbles produced significantly higher patency and flow scores than did US with saline (p < 0.01). US with IV microbubbles had higher success rates in recanalizing thrombosed grafts than did US alone at all intensities. Attenuation reduced the rate at which successful recanalization occurred at both low and high intensities. US and microbubbles are capable of recanalizing acute arteriovenous graft thromboses. Higher intensities may be needed in the presence of tissue attenuation.
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Affiliation(s)
- Feng Xie
- Internal Medicine/Cardiology Department, University of Nebraska Medical Center, Omaha, NE 68196-1165, USA
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Tsutsui JM, Elhendy A, Xie F, O'Leary EL, McGrain AC, Porter TR. Safety of dobutamine stress real-time myocardial contrast echocardiography. J Am Coll Cardiol 2005; 45:1235-42. [PMID: 15837255 DOI: 10.1016/j.jacc.2005.01.024] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2004] [Revised: 12/09/2004] [Accepted: 01/04/2005] [Indexed: 10/25/2022]
Abstract
OBJECTIVES The aim of this study was to determine the safety of dobutamine stress myocardial perfusion imaging (MPI) obtained by real-time contrast echocardiography (RTCE) and intravenous ultrasound contrast in a large cohort of patients with suspected coronary artery disease (CAD). BACKGROUND Despite the increasing number of studies showing the potential clinical utility of myocardial contrast perfusion imaging with commercially available contrast agents, the safety of this technique in a clinical setting has not been demonstrated. METHODS Over a four-year period, 1,486 patients underwent dobutamine stress RTCE with low mechanical index pulse sequence schemes after intravenous injections of commercially available contrast agents (35% Definity, Bristol Myers Squibb Medical Imaging Inc., North Billerica, Massachusetts; 65% Optison, GE-Amersham, Princeton, New Jersey). The hemodynamic and adverse effects of RTCE were compared with 1,012 patients who underwent conventional dobutamine stress echocardiography (DSE) without contrast. The feasibility of image analysis was defined as the ability to analyze MPI in at least two of the three standard segments in each left ventricular wall. RESULTS No myocardial infarction or death occurred during dobutamine stress. There was no difference in the incidence of nonsustained ventricular tachycardia, sustained ventricular tachycardia, or supraventricular tachycardia during dobutamine infusion between RTCE and DSE. Myocardial perfusion imaging was considered feasible for analysis in 94% of the walls at baseline and 95% at peak stress. The anterior, lateral, and posterior walls were the most common regions in which MPI was not feasible. Myocardial perfusion imaging with RTCE had a higher accuracy for detecting patients with angiographically significant CAD than the analysis of wall motion (84% vs. 66%, respectively; p < 0.001). CONCLUSIONS Dobutamine stress RTCE appears to be a safe and feasible technique for evaluating patients with known or suspected CAD.
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Affiliation(s)
- Jeane M Tsutsui
- Department of Internal Medicine, Section of Cardiology, University of Nebraska Medical Center, Omaha, Nebraska 68198-1165, USA
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40
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Tsutsui JM, Grayburn PA, Xie F, Porter TR. Drug and gene delivery and enhancement of thrombolysis using ultrasound and microbubbles. Cardiol Clin 2004; 22:299-312, vii. [PMID: 15158941 DOI: 10.1016/j.ccl.2004.02.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
This article reviews some important characteristics of microbubbles that give them therapeutic properties. It discusses the use of microbubbles and ultrasound for targeted delivery of adenovirus and nonviral vectors to myocytes and endothelial cells and for the dissolution of thrombus or potentiation of fibrinolytic agents for acutely thrombosed vessels. Potential applications, such as induction of angiogenesis, inhibition of neointimal hyperplasia, and in the setting of acute myocardial infarction and ischemic stroke,are discussed briefly.
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Affiliation(s)
- Jeane Mike Tsutsui
- Section of Cardiology, Department of Internal Medicine, University of Nebraska Medical Center, 600 South 42nd Street, Omaha, NE 68198, USA
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Culp WC, Porter TR, Lowery J, Xie F, Roberson PK, Marky L. Intracranial Clot Lysis With Intravenous Microbubbles and Transcranial Ultrasound in Swine. Stroke 2004; 35:2407-11. [PMID: 15322299 DOI: 10.1161/01.str.0000140890.86779.79] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background and Purpose—
Destruction of microbubbles by transcutaneous low-frequency ultrasound (LFUS) has been used to lyse adjacent clot and recanalize acutely thrombosed vessels. LFUS with intraarterial microbubbles has been shown to lyse cerebral clot rapidly in pigs without thrombolytic drugs. We hypothesized that intravenous platelet-targeted microbubbles with LFUS may be a rapid noninvasive technique to recanalize thrombosed intracerebral vessels.
Methods—
After angiography, 0.5 cc of autogenous thrombus was injected into 1 ascending pharyngeal artery of a pig, occluding it and the rete mirabile. These vessels connect the carotid to the internal carotid and are the main cerebral blood supply. Saline control or intravenous decafluorobutane-sonicated dextrose albumin microbubbles tagged with a subtherapeutic quantity of glycoprotein 2b/3a receptor inhibitor eptifibatide (75 U/kg plus 12 cc of microbubbles administered over 21 minutes), or eptifibatide control, was given with transcutaneous temporal LFUS (1 MHz at 2.0 W/cm
2
) for 24 minutes. Angiography followed with scoring of declotting and flow. The same protocol was repeated on the contralateral side with the other test fluid so each animal received a saline control and either tagged microbubble or eptifibatide alone.
Results—
Fifteen pigs completed the protocol with a mean clot age of 4.6 hours. Using tagged microbubbles, 6 of 8 achieved success compared with 0 of 7 receiving eptifibatide alone (
P
=0.007) and 1 of 15 receiving saline alone (
P
=0.02).
Conclusions—
Intravenous platelet-targeted microbubbles combined with transcranial LFUS can rapidly open acute intracranial thrombotic occlusions. Further development for ischemic stroke therapy is justified.
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Affiliation(s)
- William C Culp
- Department of Radiology, University of Arkansas for Medical Sciences, 4301 W Markham St, Slot 556, Little Rock, AR 72205-7199, USA.
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Lindner JR. Microbubbles in medical imaging: current applications and future directions. Nat Rev Drug Discov 2004; 3:527-32. [PMID: 15173842 DOI: 10.1038/nrd1417] [Citation(s) in RCA: 529] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Jonathan R Lindner
- Cardiovascular Division, University of Virginia Medical Center, Charlottesville, Virginia 22908, USA.
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Cintas P, Nguyen F, Boneu B, Larrue V. Enhancement of enzymatic fibrinolysis with 2-MHz ultrasound and microbubbles. J Thromb Haemost 2004; 2:1163-6. [PMID: 15219200 DOI: 10.1111/j.1538-7836.2004.00746.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND Microbubbles used for echo-contrast agents accelerate enzymatic fibrinolysis of clots exposed to low-frequency ultrasound (US). It is not known whether microbubbles are also effective in enhancing high-frequency US-driven enzymatic fibrinolysis. METHODS AND RESULTS Calibrated whole blood clots were exposed to US, or US and galactose-based microbubbles (Levovist), with or without recombinant tissue plasminogen activator (rt-PA) in an in-vitro flow system. We used low-intensity, 2-MHz, pulsed wave US. Relative weight reduction of clot +/- SD was 30.7 +/- 9.5% after exposure to microbubbles, rt-PA and US, 13.1 +/- 2.6% after exposure to rt-PA and US, 10.9 +/- 3.6% after exposure to microbubbles and US, and 6.1 +/- 1.9% after exposure to US alone. anova demonstrated a significant effect of rt-PA (P =0.001), microbubbles (P = 0.012), and interaction of both (P = 0.022). CONCLUSIONS The application of galactose-based microbubbles (Levovist) strongly accelerates lysis of clots exposed to 2 MHz, low-intensity US in vitro both with and without rt-PA. The findings suggest a synergy between microbubbles and rt-PA. These methods routinely used for transcranial diagnostic applications have the potential to improve the efficacy of intravenous rt-PA in acute ischemic stroke.
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Affiliation(s)
- P Cintas
- Departments of Neurology and Hematology, EA2049, University of Toulouse, Toulouse, France
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Unger EC, Porter T, Culp W, Labell R, Matsunaga T, Zutshi R. Therapeutic applications of lipid-coated microbubbles. Adv Drug Deliv Rev 2004; 56:1291-314. [PMID: 15109770 DOI: 10.1016/j.addr.2003.12.006] [Citation(s) in RCA: 377] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2003] [Accepted: 12/20/2003] [Indexed: 11/15/2022]
Abstract
Lipid-coated microbubbles represent a new class of agents with both diagnostic and therapeutic applications. Microbubbles have low density. Stabilization of microbubbles by lipid coatings creates low-density particles with unusual properties for diagnostic imaging and drug delivery. Perfluorocarbon (PFC) gases entrapped within lipid coatings make microbubbles that are sufficiently stable for circulation in the vasculature as blood pool agents. Microbubbles can be cavitated with ultrasound energy for site-specific local delivery of bioactive materials and for treatment of vascular thrombosis. The blood-brain barrier (BBB) can be reversibly opened without damaging the neurons using ultrasound applied across the intact skull to cavitate microbubbles within the cerebral microvasculature for delivery of both low and high molecular weight therapeutic compounds to the brain. The first lipid-coated PFC microbubble product is currently marketed for diagnostic ultrasound imaging. Clinical trials are currently in process for treatment of vascular thrombosis with ultrasound and lipid-coated PFC microbubbles (SonoLysis Therapy). Targeted microbubbles and acoustically active PFC nanoemulsions with specific ligands can be developed for detecting disease at the molecular level and targeted drug and gene delivery. Bioactive compounds can be incorporated into these carriers for site-specific delivery. Our aim is to cover the therapeutic applications of lipid-coated microbubbles and PFC emulsions in this review.
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45
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Affiliation(s)
- Jonathan R Lindner
- Cardiovascular Division, University of Virginia Medical Center, Charlottesville, VA, USA
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