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Franzoni M, O'Connor DT, Marcar L, Power D, Moloney MA, Kavanagh EG, Leask RL, Nolan J, Kiely PA, Walsh MT. The Presence of a High Peak Feature Within Low-Average Shear Stimuli Induces Quiescence in Venous Endothelial Cells. Ann Biomed Eng 2019; 48:582-594. [PMID: 31555984 DOI: 10.1007/s10439-019-02371-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 09/18/2019] [Indexed: 11/24/2022]
Abstract
Wall shear stress (WSS) is an important stimulus in vascular remodelling and vascular lesion development. The current methods to assess and predict the risk associated with specific unsteady WSS consider the WSS mean values or the presence of reverse phases described by the oscillatory shear index. Recent evidence has shown that the accuracy of these methods is limited, especially with respect to the venous environment. Unsteady WSS are characterised by several features that may individually affect endothelial cells. Consequently, we assessed the effects of averaged WSS (TAWSS), temporal WSS gradient (TWSSG), maximum WSS (WSS peak) and reverse phase (OSI) by applying different WSS profiles to venous EC in-vitro, using a real-time controlled cone-and-plate cell-shearing device for 24 h. We found that TWSSG and WSS peak affect cell elongation and alignment respectively. We also found that the WSS waveforms with a peak of 1.5 Pa or higher significantly correlate with the induction of a protective phenotype. Cell phenotype induced by these high peak waveforms does not correlate to what is predicted by the hemodynamic indices currently used. The definition of reliable hemodynamic indices can be used to inform the computational models aimed at estimating the hemodynamic effects on vascular remodelling.
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Affiliation(s)
- M Franzoni
- School of Engineering, Bernal Institute, University of Limerick, Limerick, V94 T9PX, Ireland.,Health Research Institute, University of Limerick, Limerick, Ireland
| | - D T O'Connor
- School of Engineering, Bernal Institute, University of Limerick, Limerick, V94 T9PX, Ireland.,Health Research Institute, University of Limerick, Limerick, Ireland
| | - L Marcar
- School of Engineering, Bernal Institute, University of Limerick, Limerick, V94 T9PX, Ireland
| | - D Power
- Health Research Institute, University of Limerick, Limerick, Ireland.,Department of Vascular Surgery, University Hospital Limerick, Limerick, Ireland
| | - M A Moloney
- Health Research Institute, University of Limerick, Limerick, Ireland.,Department of Vascular Surgery, University Hospital Limerick, Limerick, Ireland
| | - E G Kavanagh
- Health Research Institute, University of Limerick, Limerick, Ireland.,Department of Vascular Surgery, University Hospital Limerick, Limerick, Ireland
| | - R L Leask
- Department of Chemical Engineering, McGill University, Montreal, Canada
| | - J Nolan
- Health Research Institute, University of Limerick, Limerick, Ireland.,Graduate Entry Medical School, Faculty of Education and Health Sciences, University of Limerick, Limerick, Ireland
| | - P A Kiely
- Health Research Institute, University of Limerick, Limerick, Ireland.,Graduate Entry Medical School, Faculty of Education and Health Sciences, University of Limerick, Limerick, Ireland
| | - M T Walsh
- School of Engineering, Bernal Institute, University of Limerick, Limerick, V94 T9PX, Ireland. .,Health Research Institute, University of Limerick, Limerick, Ireland.
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Barrett HE, Cunnane EM, O Brien JM, Moloney MA, Kavanagh EG, Walsh MT. On the effect of computed tomography resolution to distinguish between abdominal aortic aneurysm wall tissue and calcification: A proof of concept. Eur J Radiol 2017; 95:370-377. [PMID: 28987694 DOI: 10.1016/j.ejrad.2017.08.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Revised: 08/16/2017] [Accepted: 08/22/2017] [Indexed: 12/15/2022]
Abstract
PURPOSE The purpose of this study is to determine the optimal target CT spatial resolution for accurately imaging abdominal aortic aneurysm (AAA) wall characteristics, distinguishing between tissue and calcification components, for an accurate assessment of rupture risk. MATERIALS AND METHODS Ruptured and non-ruptured AAA-wall samples were acquired from eight patients undergoing open surgical aneurysm repair upon institutional review board approval and informed consent was obtained from all patients. Physical measurements of AAA-wall cross-section were made using scanning electron microscopy. Samples were scanned using high resolution micro-CT scanning. A resolution range of 15.5-155μm was used to quantify the influence of decreasing resolution on wall area measurements, in terms of tissue and calcification. A statistical comparison between the reference resolution (15.5μm) and multi-detector CT resolution (744μm) was also made. RESULTS Electron microscopy examination of ruptured AAAs revealed extremely thin outer tissue structure <200μm in radial distribution which is supporting the aneurysm wall along with large areas of adjacent medial calcifications far greater in area than the tissue layer. The spatial resolution of 155μm is a significant predictor of the reference AAA-wall tissue and calcification area measurements (r=0.850; p<0.001; r=0.999; p<0.001 respectively). The tissue and calcification area at 155μm is correct within 8.8%±1.86 and 26.13%±9.40 respectively with sensitivity of 87.17% when compared to the reference. CONCLUSION The inclusion of AAA-wall measurements, through the use of high resolution-CT will elucidate the variations in AAA-wall tissue and calcification distributions across the wall which may help to leverage an improved assessment of AAA rupture risk.
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Affiliation(s)
- H E Barrett
- Centre for Applied Biomedical Engineering Research (CABER), Health Research Institute (HRI), School of Engineering, Bernal Institute, University of Limerick, Lonsdale Building, Limerick, Ireland
| | - E M Cunnane
- Centre for Applied Biomedical Engineering Research (CABER), Health Research Institute (HRI), School of Engineering, Bernal Institute, University of Limerick, Lonsdale Building, Limerick, Ireland
| | - J M O Brien
- Department of Radiology, University Hospital Limerick, Ireland
| | - M A Moloney
- Department of Vascular Surgery, University Hospital Limerick, Ireland
| | - E G Kavanagh
- Department of Vascular Surgery, University Hospital Limerick, Ireland
| | - M T Walsh
- Centre for Applied Biomedical Engineering Research (CABER), Health Research Institute (HRI), School of Engineering, Bernal Institute, University of Limerick, Lonsdale Building, Limerick, Ireland.
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Owens M, Mohan H, Moloney MA, Roche-Nagle G, Baker J, Sheehan S, Mehigan D, Barry M. Patient knowledge of peripheral vascular disease in an outpatient setting: an Achilles heel? Ir Med J 2013; 106:116-118. [PMID: 23691846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Peripheral vascular disease (PVD) has numerous modifiable risk factors. This study aimed to establish patients' awareness of risk factors and causes of PVD and their understanding of mechanisms of secondary prevention. A prospective survey of awareness of PVD among patients attending a tertiary vascular clinic for management of peripheral vascular disease was undertaken. Institutional review board approval was granted. Statistical analysis was performed using SPSS version 18.0 software. There was a 100% response rate, with 97 participants (53 male). Seventeen patients (19%) reported an interval of greater than six months from the onset of symptoms to first seeking medical attention with their General Practitioner. Only 19 (20%) could correctly identify 3 or more risk factors for peripheral vascular disease. Patients have limited awareness of PVD and its consequences. Educational initiatives are needed to encourage patients to seek early medical attention and raise awareness of modifiable risk factors in the community.
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Affiliation(s)
- M Owens
- St Vincent's University Hospital, Elm Park, Dublin 4.
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Moloney MA, McHugh S, O’ Donnell DH, Casey RG, Kavanagh EG, Grace PA, Fitzgerald P, Bouchier-Hayes DJ. Comparison of arterial stiffness and microcirculatory changes following abdominal aortic aneurysm grafting. Ir J Med Sci 2010; 180:375-8. [DOI: 10.1007/s11845-010-0513-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Accepted: 05/24/2010] [Indexed: 10/18/2022]
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Collins D, Moloney MA, O'Donnell D, Brophy D, Sheehan SJ. Acute aortic occlusion in a patient with heparin-induced thrombocytopenia treated by thrombectomy. Ir J Med Sci 2010; 181:397-400. [PMID: 20665120 DOI: 10.1007/s11845-010-0531-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Accepted: 07/08/2010] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Heparin-induced thrombocytopenia syndrome (HITS) is an infrequent complication of heparin anticoagulation. CASE REPORT We present the case of a 44-year-old male who was admitted with acute ischaemia of his right lower limb. He was initially treated with unfractionated heparin and thrombolysis, but subsequently developed acute aortic thrombosis 8 days following initiation of heparin therapy. This was treated with bilateral per-femoral thrombectomy with curative result. CONCLUSION This case report draws the attention of surgeons to the difficulties in diagnosing HITS and highlights the multidisciplinary management of a complicated case of acute ischaemia.
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Affiliation(s)
- D Collins
- Department of Vascular Surgery, St. Vincent's University Hospital, Elm Park, Dublin 4, Ireland.
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Abstract
Femoral shaft perforation at total hip arthroplasty is a complication that is being noted more frequently, and it is often associated with femoral shaft fracture below the prosthesis. This study examines the anatomic and biomechanical effects of femoral shaft perforation at arthroplasty, and the effects of supporting the perforated bone with Partridge plates and bands. Two models, pig femora and Pedilen cylinders, were employed. Testing the bone models to failure in tensile mode showed that the perforations weakened the bone and that the Partridge plates and bands decreased the weakening effects of the perforation. The strengthening effect of the Partridge plates and bands on the bone with a perforation, allied with the presence of an internal splint in the event of a fracture through the perforation, suggests the benefit of using Partridge plates and bands if a cortical perforation is found at arthroplasty and revision is not feasible.
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Affiliation(s)
- J Doyle
- Department of Orthopedics, University of South Florida, Tampa 33606
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Abstract
Perforation of the femoral shaft at total hip arthroplasty is a complication which is being reported more frequently. It has been suggested that the presence of bone cement in the perforation decreases the weakening effect of the perforation, but the mechanical basis for this belief is dubious. The anatomy of perforation was studied by cadaver dissection and its mechanical consequences were assessed in two models using Pedilen, a polyurethane foam, and pig femora. It was found that cement in a hole in bone decreased the weakening effect of the hole to tensile stress.
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Affiliation(s)
- J Doyle
- Cappagh Orthopaedic Hospital, Dublin, Ireland
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