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“No-Touch” versus “Endo” Vein Harvest: Early Patency on Symptom-Directed Catheterization and Harvest Site Complications. INNOVATIONS-TECHNOLOGY AND TECHNIQUES IN CARDIOTHORACIC AND VASCULAR SURGERY 2019; 9:306-11. [DOI: 10.1097/imi.0000000000000084] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Objective “No-touch” (NT) saphenous vein harvesting preserves the adventitial vasa vasorum, prevents medial ischemia, and is associated with an improved short-term and long-term vein graft patency. It may also be associated with a higher rate of harvest site complications. Endovascular vein harvesting (endo-vein) has a low rate of harvest site complications but also a tendency toward a lower patency rate. Methods During a 2-year period (2011–2012), we compared the vein graft patency at symptom-directed cardiac catheterization as well as wound complication rates in 210 patients who received either NT (87 patients) or endo-vein (123 patients). Results The recatheterization rate for the two groups was similar: 9 (10.3%) of 87 of the NT patients versus 11 (9.0%) of 123 of the endo-vein patients. There was a significant difference in vein graft patency between the groups: 15 (94%) of 16 NT vein grafts were patent versus 6 (27%) of 22 of endo-veins ( P < 0.02). The endo-vein graft patency during this 2-year period was similar to the total endo-vein patency (37%) during a 4-year period. A comparison between a more experienced and a less experienced harvester revealed no difference in patency rate. Harvest site complications were significantly higher with the NT harvest: 18% of the NT patients requiring vacuum-assisted wound closure or intravenous antibiotics versus 2% of the endo-vein patients ( P < 0.0001). The application of platelet-rich plasma did not significantly lower wound complication rates ( P = 0.27). Conclusions These results suggest that NT vein harvesting may be associated with improved graft patency, but methods should be developed to lower wound complication rates.
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Mannion JD, Marelli D, Brandt T, Stallings M, Cirks J, Dreifaldt M, Souza D. “No-Touch” versus “Endo” Vein Harvest: Early Patency on Symptom-Directed Catheterization and Harvest Site Complications. INNOVATIONS-TECHNOLOGY AND TECHNIQUES IN CARDIOTHORACIC AND VASCULAR SURGERY 2014. [DOI: 10.1177/155698451400900409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- John D. Mannion
- Division of Cardiac Surgery, Department of Surgery, Bayhealth Medical Center, Dover, DE USA
| | - Daniel Marelli
- Division of Cardiac Surgery, Department of Surgery, Bayhealth Medical Center, Dover, DE USA
| | - Todd Brandt
- Division of Cardiac Surgery, Department of Surgery, Bayhealth Medical Center, Dover, DE USA
| | - Megan Stallings
- Division of Cardiac Surgery, Department of Surgery, Bayhealth Medical Center, Dover, DE USA
| | - Jeffery Cirks
- Division of Cardiac Surgery, Department of Surgery, Bayhealth Medical Center, Dover, DE USA
| | - Mats Dreifaldt
- Department of Thoracic and Cardiovascular Surgery, Orebro University Hospital, Orebro, Sweden
| | - Domingos Souza
- Department of Thoracic and Cardiovascular Surgery, Orebro University Hospital, Orebro, Sweden
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3
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Teng Z, Sadat U, Brown AJ, Gillard JH. Plaque hemorrhage in carotid artery disease: pathogenesis, clinical and biomechanical considerations. J Biomech 2014; 47:847-58. [PMID: 24485514 PMCID: PMC3994507 DOI: 10.1016/j.jbiomech.2014.01.013] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/13/2014] [Indexed: 12/21/2022]
Abstract
Stroke remains the most prevalent disabling illness today, with internal carotid artery luminal stenosis due to atheroma formation responsible for the majority of ischemic cerebrovascular events. Severity of luminal stenosis continues to dictate both patient risk stratification and the likelihood of surgical intervention. But there is growing evidence to suggest that plaque morphology may help improve pre-existing risk stratification criteria. Plaque components such a fibrous tissue, lipid rich necrotic core and calcium have been well investigated but plaque hemorrhage (PH) has been somewhat overlooked. In this review we discuss the pathogenesis of PH, its role in dictating plaque vulnerability, PH imaging techniques, marterial properties of atherosclerotic tissues, in particular, those obtained based on in vivo measurements and effect of PH in modulating local biomechanics.
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Affiliation(s)
- Zhongzhao Teng
- University Department of Radiology, University of Cambridge, UK; Department of Engineering, University of Cambridge, UK.
| | - Umar Sadat
- Department of Surgery, Cambridge University Hospitals NHS Foundation Trust, UK
| | - Adam J Brown
- Department of Cardiovascular Medicine, University of Cambridge, UK
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4
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The No-Touch Saphenous Vein as the Preferred Second Conduit for Coronary Artery Bypass Grafting. Ann Thorac Surg 2013; 96:105-11. [DOI: 10.1016/j.athoracsur.2013.01.102] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Revised: 01/24/2013] [Accepted: 01/29/2013] [Indexed: 11/30/2022]
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5
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Teng Z, Degnan AJ, Sadat U, Wang F, Young VE, Graves MJ, Chen S, Gillard JH. Characterization of healing following atherosclerotic carotid plaque rupture in acutely symptomatic patients: an exploratory study using in vivo cardiovascular magnetic resonance. J Cardiovasc Magn Reson 2011; 13:64. [PMID: 22032404 PMCID: PMC3215655 DOI: 10.1186/1532-429x-13-64] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Accepted: 10/27/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Carotid plaque rupture, characterized by ruptured fibrous cap (FC), is associated with subsequent cerebrovascular events. However, ruptured FC may heal following stroke and convey decreased risk of future events. This study aims to characterize the healing process of ruptured FC by assessing the lumen conditions, quantified by the lumen curvature and roughness, using in vivo carotid cardiovascular magnetic resonance (CMR). METHODS Patients suffering from transient ischemic attack underwent high resolution carotid MR imaging within 72 hours of the acute cerebrovascular ischemic event. CMR imaging was repeated at 3 and 12 months in 26 patients, in whom FC rupture/erosion was observed on baseline images and subsequent cerebrovascular events were recorded during the follow-up period. Lumen curvature and roughness were quantified from carotid CMR images and changes in these values were monitored on follow-up imaging. RESULTS Healing of ruptured plaque was observed in patients (23 out of 26) without any ischemic symptom recurrence as shown by the lumen surface becoming smoother during the follow-up period, characterized by decreasing maximum lumen curvature (p < 0.05), increasing minimum lumen curvature (p < 0.05) and decreasing lumen roughness (p < 0.05) during the one year follow-up period. CONCLUSIONS Carotid plaque healing can be assessed by quantification of the lumen curvature and roughness and the incidence of recurrent cerebrovascular events may be high in plaques that do not heal with time. The assessment of plaque healing may facilitate risk stratification of recent stroke patients on the basis of CMR results.
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Affiliation(s)
- Zhongzhao Teng
- University Department of Radiology, University of Cambridge, UK
- Department of Engineering, University of Cambridge, UK
| | - Andrew J Degnan
- University Department of Radiology, University of Cambridge, UK
| | - Umar Sadat
- University Department of Radiology, University of Cambridge, UK
- Department of Surgery, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Fang Wang
- College of Computer Science and Technology, Zhejiang University of Technology, Hangzhou, China
| | | | - Martin J Graves
- University Department of Radiology, University of Cambridge, UK
| | - Shengyong Chen
- College of Computer Science and Technology, Zhejiang University of Technology, Hangzhou, China
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6
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Teng Z, Sadat U, Huang Y, Young V, Graves M, Lu J, Gillard J. In vivo MRI-based 3D Mechanical Stress–Strain Profiles of Carotid Plaques with Juxtaluminal Plaque Haemorrhage: An Exploratory Study for the Mechanism of Subsequent Cerebrovascular Events. Eur J Vasc Endovasc Surg 2011; 42:427-33. [DOI: 10.1016/j.ejvs.2011.05.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Accepted: 05/09/2011] [Indexed: 11/30/2022]
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7
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Madrigal-Matute J, Martin-Ventura JL, Blanco-Colio LM, Egido J, Michel JB, Meilhac O. Heat-shock proteins in cardiovascular disease. Adv Clin Chem 2011; 54:1-43. [PMID: 21874755 DOI: 10.1016/b978-0-12-387025-4.00001-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Heat-shock proteins (HSPs) belong to a group of highly conserved families of proteins expressed by all cells and organisms and their expression may be constitutive or inducible. They are generally considered as protective molecules against different types of stress and have numerous intracellular functions. Secretion or release of HSPs has also been described, and potential roles for extracellular HSPs reported. HSP expression is modulated by different stimuli involved in all steps of atherogenesis including oxidative stress, proteolytic aggression, or inflammation. Also, antibodies to HSPs may be used to monitor the response to different types of stress able to induce changes in HSP levels. In the present review, we will focus on the potential implication of HSPs in atherogenesis and discuss the limitations to the use of HSPs and anti-HSPs as biomarkers of atherothrombosis. HSPs could also be considered as potential therapeutic targets to reinforce vascular defenses and delay or avoid clinical complications associated with atherothrombosis.
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Affiliation(s)
- Julio Madrigal-Matute
- Vascular Research Lab, IIS, Fundación Jiménez Díaz, Autónoma University, Av. Reyes Católicos 2, Madrid, Spain
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8
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Postprocedure Administration of Insulin in Canine Autologous Vein Grafting: A Potential Strategy to Attenuate Intimal Hyperplasia. J Cardiovasc Pharmacol 2010; 56:402-12. [DOI: 10.1097/fjc.0b013e3181f09ba8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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9
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Desai M, Mirzay-Razzaz J, von Delft D, Sarkar S, Hamilton G, Seifalian AM. Inhibition of neointimal formation and hyperplasia in vein grafts by external stent/sheath. Vasc Med 2010; 15:287-97. [DOI: 10.1177/1358863x10366479] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Synthetic and to a lesser extent vein graft failure is still a major problem in the treatment of peripheral arterial disease, with neointimal hyperplasia being the main cause for graft occlusion in the medium and long term. This review aims to establish the current status of external stents or sheaths in the prevention of intimal hyperplasia in small diameter (< 6 mm) vein grafts.
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Affiliation(s)
- Mital Desai
- Centre for Nanotechnology and Regenerative Medicine, Division of Surgery & Interventional Science, University College London, London, UK, Cardiovascular Haemodynamic Group, University College London, London, UK
| | - Jalaledin Mirzay-Razzaz
- Centre for Nanotechnology and Regenerative Medicine, Division of Surgery & Interventional Science, University College London, London, UK, Cardiovascular Haemodynamic Group, University College London, London, UK
| | - Dirk von Delft
- Christiaan Barnard Division of Cardiothoracic Surgery, University of Cape Town, Cape Town, South Africa
| | - Sandip Sarkar
- Centre for Nanotechnology and Regenerative Medicine, Division of Surgery & Interventional Science, University College London, London, UK
| | - George Hamilton
- Vascular Unit, Royal Free Hampstead NHS Trust Hospital, London, UK
| | - Alexander M Seifalian
- Centre for Nanotechnology and Regenerative Medicine, Division of Surgery & Interventional Science, University College London, London, UK, Cardiovascular Haemodynamic Group, University College London, London, UK,
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10
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Owens CD. Adaptive changes in autogenous vein grafts for arterial reconstruction: clinical implications. J Vasc Surg 2009; 51:736-46. [PMID: 19837532 DOI: 10.1016/j.jvs.2009.07.102] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2009] [Revised: 07/20/2009] [Accepted: 07/24/2009] [Indexed: 01/22/2023]
Abstract
For patients with the most severe manifestations of lower extremity arterial occlusive disease, bypass surgery using autogenous vein has been the most durable reconstruction. However, the incidence of bypass graft stenosis and graft failure remains substantial and wholesale improvements in patency are lacking. One potential explanation is that stenosis arises not only from over exuberant intimal hyperplasia, but also due to insufficient adaptation or remodeling of the vein to the arterial environment. Although in vivo human studies are difficult to conduct, recent advances in imaging technology have made possible a more comprehensive structural examination of vein bypass maturation. This review summarizes recent translational efforts to understand the structural and functional properties of human vein grafts and places it within the context of the rich existing literature of vein graft failure.
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Affiliation(s)
- Christopher D Owens
- Division of Vascular and Endovascular Surgery, University of California San Francisco, San Francisco, CA 94143, USA.
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11
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de Graaf R, Tintu A, Stassen F, Kloppenburg G, Bruggeman C, Rouwet E. N-acetylcysteine prevents neointima formation in experimental venous bypass grafts. Br J Surg 2009; 96:941-50. [DOI: 10.1002/bjs.6659] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract
Background
Neointima formation, mainly characterized by smooth muscle cell proliferation, is an important cause of venous bypass graft failure. The therapeutic potential of the antioxidant N-acetylcysteine (NAC) to attenuate smooth muscle cell proliferation and neointima formation was examined in vivo. The effects of NAC on hyperoxia-induced venous smooth muscle cell (VSMC) cytokine production and proliferation were addressed in vitro.
Methods
Rats underwent autologous epigastric vein-to-femoral artery interposition grafting. Fourteen rats received oral NAC, and a similar control group received saline. Histomorphometric analysis was performed after 7 days or 3 weeks. Cytokine analysis and cell proliferation assay were performed in cultured human VSMCs after hyperoxic or normoxic exposure and NAC administration.
Results
NAC-treated rats displayed a threefold reduction in neointimal area, a sixfold reduction in stenosis rate, and a twofold reduction in VSMC proliferation after vein graft surgery. Incubation of VSMCs in 70 per cent oxygen stimulated the release of mitogenic inflammatory cytokines interleukin (IL) 6 and IL-8. Cytokine-rich medium from these VSMCs induced proliferation of normoxic VSMCs. NAC inhibited hyperoxia-induced cytokine release and VSMC proliferation.
Conclusion
NAC attenuated neointima formation and vein graft stenosis by reducing VSMC proliferation in vivo, and prevented hyperoxia-induced cytokine production and VSMC proliferation in vitro.
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Affiliation(s)
- R de Graaf
- Department of Surgery, Cardiovascular Research Institute Maastricht, University of Maastricht, Maastricht, The Netherlands
- Department of Radiology, Cardiovascular Research Institute Maastricht, University of Maastricht, Maastricht, The Netherlands
| | - A Tintu
- Department of Surgery, Cardiovascular Research Institute Maastricht, University of Maastricht, Maastricht, The Netherlands
- Department of Clinical Chemistry, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - F Stassen
- Department of Medical Microbiology, Cardiovascular Research Institute Maastricht, University of Maastricht, Maastricht, The Netherlands
| | - G Kloppenburg
- Department of Medical Microbiology, Cardiovascular Research Institute Maastricht, University of Maastricht, Maastricht, The Netherlands
| | - C Bruggeman
- Department of Medical Microbiology, Cardiovascular Research Institute Maastricht, University of Maastricht, Maastricht, The Netherlands
| | - E Rouwet
- Department of Surgery, Erasmus University Medical Center, Rotterdam, The Netherlands
- Department of Surgery, Atrium Medical Centre Parkstad, Heerlen, The Netherlands
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12
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Cilostazol suppresses neointimal hyperplasia in canine vein grafts. Surg Today 2009; 39:128-32. [DOI: 10.1007/s00595-008-3819-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2008] [Accepted: 05/14/2008] [Indexed: 11/27/2022]
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13
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Abstract
Nogo-B was recently identified as a novel vascular marker; the normally high vascular expression of Nogo-B is rapidly lost following vascular injury. Here we assess the potential therapeutic effects of Ad-Nogo-B delivery to injured vessels in vivo. Nogo-B overexpression following Ad-Ng-B infection of vascular smooth muscle cells (VSMCs) was shown to block proliferation and migration in a dose-dependent manner in vitro. We next assessed the effects of Ad-Ng-B treatment on neointima formation in two in vivo models of acute vascular injury. Adventitial delivery of Ad-Ng-B to wire-injured murine femoral arteries led to a significant decrease in the intimal area [0.014 mm(2) versus 0.030 mm(2) (P = 0.049)] and the intima:media ratio [0.78 versus 1.67 (P = 0.038)] as compared to the effects of Ad-beta-Gal control virus at 21 days after injury. Similarly, lumenal delivery of Ad-Ng-B to porcine saphenous veins prior to carotid artery grafting significantly reduced the intimal area [2.87 mm(2) versus 7.44 mm(2) (P = 0.0007)] and the intima:media ratio [0.32 versus 0.55 (P = 0.0044)] as compared to the effects following the delivery of Ad- beta-Gal, at 28 days after grafting. Intimal VSMC proliferation was significantly reduced in both the murine and porcine disease models. Gene delivery of Nogo-B exerts a positive effect on vascular injury-induced remodeling and reduces neointimal development in two arterial and venous models of vascular injury.
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14
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Teng ZZ, Ji GY, Chu HJ, Li ZY, Zou LJ, Xu ZY, Huang SD. Does PGA external stenting reduce compliance mismatch in venous grafts? Biomed Eng Online 2007; 6:12. [PMID: 17437638 PMCID: PMC1860003 DOI: 10.1186/1475-925x-6-12] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2006] [Accepted: 04/16/2007] [Indexed: 11/26/2022] Open
Abstract
Background Autogenous vein grafting is widely used in regular bypassing procedures. Due to its mismatch with the host artery in both mechanical property and geometry, the graft often over expands under high arterial blood pressure and forms a step-depth where eddy flow develops, thus causing restenosis, fibrous graft wall, etc. External stents, such as sheaths being used to cuff the graft, have been introduced to eliminate these mismatches and increase the patency. Although histological and immunochemical studies have shown some positive effects of the external stent, the mechanical mismatch under the protection of an external stent remains poorly analyzed. Methods In this study, the jugular veins taken from hypercholesterolemic rabbits were transplanted into the carotid arteries, and non-woven polyglycolic acid (PGA) fabric was used to fabricate the external stents to study the effect of the biodegradable external stent. Eight weeks after the operation, the grafts were harvested to perform mechanical tests and histological examinations. An arc tangent function was suggested to describe the relationship between pressure and cross-sectional area to analyse the compliance of the graft. Results The results from the mechanical tests indicated that grafts either with or without external stents displayed large compliance in the low-pressure range and were almost inextensible in the high-pressure range. This was very different from the behavior of the arteries or veins in vivo. The data from histological tests showed that, with external stents, collagen fibers were more compact, whilst those in the graft without protection were looser and thicker. No elastic fiber was found in either kind of grafts. Furthermore, grafts without protection were over-expanded which resulted in much bigger cross-sectional areas. Conclusion The PGA external extent contributes little to the reduction of the mechanical mismatch between the graft and its host artery while remodeling develops. For the geometric mismatch, it reduces the cross-section area, therefore matching with the host artery much better. Although there are some positive effects, conclusively the PGA is not an ideal material for external stent.
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Affiliation(s)
- Zhong-zhao Teng
- Aragon Institute of Engineering Research (I3A), University of Zaragoza, Spain
| | - Guang-yu Ji
- Department of Cardiothocacic Surgery, Changhai Hospital, Shanghai, China
| | - Hong-jun Chu
- Department of Cardiothocacic Surgery, Changhai Hospital, Shanghai, China
| | - Zhi-Yong Li
- Departments of Engineering & Radiology, University of Cambridge, Cambridge CB2 2QQ UK
| | - Liang-jian Zou
- Department of Cardiothocacic Surgery, Changhai Hospital, Shanghai, China
| | - Zhi-yun Xu
- Department of Cardiothocacic Surgery, Changhai Hospital, Shanghai, China
| | - Sheng-dong Huang
- Department of Cardiothocacic Surgery, Changhai Hospital, Shanghai, China
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15
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Zhao J, Andreasen JJ, Yang J, Rasmussen BS, Liao D, Gregersen H. Manual pressure distension of the human saphenous vein changes its biomechanical properties—implication for coronary artery bypass grafting. J Biomech 2007; 40:2268-76. [PMID: 17141248 DOI: 10.1016/j.jbiomech.2006.10.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2006] [Accepted: 10/12/2006] [Indexed: 11/18/2022]
Abstract
Patency rates of saphenous vein grafts following coronary artery bypass grafting (CABG) depend on multiple factors. Information regarding the impact of biomechanical properties of vein grafts on patency rates is not available. The objective of the present study was to evaluate whether uncontrolled manual pressure distension during routine preparation of the saphenous vein in CABG-induced changes in the biomechanical properties of the vein. The morphometric and stress-strain properties were studied in isolated segments of the saphenous vein from 12 patients undergoing elective CABG. Six segments were manually distended without pressure control and six were not distended. The mechanical test was performed as a ramp inflation using syringe pump. The vein dimensions were obtained from digitised images at different pressures as well as at the no-load and zero-stress states. The circumferences, the wall and lumen area, the wall thickness, and the outer diameter as function of the applied pressure were largest in the segments with uncontrolled manual distension compared to those without distension (P<0.05). The opening angle and the absolute value of the residual strains were lower (P<0.01) and the circumferential stress-strain curve shifted to the left, indicating the wall became stiffer with uncontrolled manual distension compared to those without distension (P<0.05). In conclusion, manual pressure distension changed the morphometric and biomechanical properties of the saphenous vein. The perspective is that studies on biomechanical properties on the saphenous vein may guide surgeons how to handle graft material without causing major changes of the biomechanical properties during harvesting and preparation.
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Affiliation(s)
- Jingbo Zhao
- Center of Excellence in Visceral Biomechanics and Pain, Research Building, Aalborg Hospital, Aalborg, Denmark.
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16
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Owens CD, Wake N, Jacot JG, Gerhard-Herman M, Gaccione P, Belkin M, Creager MA, Conte MS. Early biomechanical changes in lower extremity vein grafts—distinct temporal phases of remodeling and wall stiffness. J Vasc Surg 2006; 44:740-6. [PMID: 16926087 DOI: 10.1016/j.jvs.2006.06.005] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2006] [Accepted: 06/06/2006] [Indexed: 11/15/2022]
Abstract
BACKGROUND The geometric and biomechanical changes that contribute to vein graft remodeling are not well established. We sought to measure patterns of adaptation in lower extremity vein grafts and assess their correlation with clinical outcomes. METHODS We conducted a prospective, longitudinal study of patients undergoing infrainguinal reconstruction with autogenous conduit. In addition to standard duplex surveillance, lumen diameter (of a defined index segment of the conduit) and pulse wave velocity (PWV) were assessed by ultrasound imaging at surgery and at 1, 3, and 6 months postoperatively. Graft dimensions and wall stiffness were correlated with clinical outcomes. RESULTS There were 92 patients and 96 limbs in this study. On average, vein graft lumen diameter increased during the first month of implantation from 0.37 +/- .01 cm to 0.45 +/- 0.02 cm (mean +/- SEM; P = .002), representing a relative change of +21.6% (median +/- 14%; range, -31 to +67%) during this period. Of the entire cohort, 72% of grafts demonstrated appreciable dilation of the index segment during the first month. Index segment lumen diameter did not change appreciably beyond 1 month, with the notable exception of arm vein conduits, which showed continued tendency to dilate. PWV increased during the first 6 months (17.2 +/- 1.2 m/s to 23.2 +/- 2.4 m/s; P = .008), reflecting a nearly 40% increase in conduit stiffness (2.0 +/- .6 Mdynes/cm to 3.3 +/- .8 Mdynes/cm, P = .01). The greatest relative increase (25%) in PWV occurred from months 1 to 3. Loss of primary patency occurred in 24 cases (19 revisions, 5 occlusions), with a mean reintervention time of 7.6 months. Grafts that demonstrated early positive remodeling (lumen dilatation) had a trend of increased primary patency (P = .08, log rank). Among the grafts that failed, a trend was noted toward greater wall stiffness at 1 month, 2.7 vs 1.5 Mdynes (P = .08). CONCLUSION Vein graft remodeling appears to involve at least two distinct temporal phases. Outward remodeling of the lumen occurs early, and wall stiffness changes occur in a more delayed fashion. Early outward remodeling may be important for successful vein graft adaptation.
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17
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Schachner T. Pharmacologic inhibition of vein graft neointimal hyperplasia. J Thorac Cardiovasc Surg 2006; 131:1065-72. [PMID: 16678591 DOI: 10.1016/j.jtcvs.2005.11.043] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2005] [Accepted: 11/16/2005] [Indexed: 11/25/2022]
Abstract
Although arterial conduits are widely used and have improved the long-term results of coronary artery bypass grafting, vein grafts remain important additional conduits in coronary surgery. Newer studies show a saphenous vein graft patency of 60% or more at 10 years postoperatively. The pathology of vein graft disease consists of thrombosis, neointimal hyperplasia, and vein graft atherosclerosis, which limit graft longevity. Therapeutic strategies to prevent vein graft disease include external stenting, pharmacotherapy, and gene therapy. The potential benefits of a pharmacologic approach are as follows: (1) Drugs with a broad clinical experience can be used; (2) side effects of systemic application can be minimized by local therapy; and (3) no vascular injury, such as pressurizing the vein for a viral transfection approach, is necessary. The different sites for pharmacotherapy in vein graft disease are reviewed in this article.
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Affiliation(s)
- Thomas Schachner
- Department of Cardiac Surgery, Innsbruck Medical University, Innsbruck, Austria.
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18
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Rotmans JI, Verhagen HJM, Velema E, de Kleijn DPV, van den Heuvel M, Kastelein JJP, Pasterkamp G, Stroes ESG. Local overexpression of C-type natriuretic peptide ameliorates vascular adaptation of porcine hemodialysis grafts. Kidney Int 2004; 65:1897-905. [PMID: 15086933 DOI: 10.1111/j.1523-1755.2004.00598.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND Outflow obstruction at the outflow tract of arteriovenous grafts contributes significantly to the poor patency rates of dialysis grafts in vivo. We addressed the potential of local periadventitial gene therapy at the outflow tract for improving access patency in a validated porcine model of arteriovenous grafts using an adenoviral vector encoding murine C-type natriuretic peptide (Ad.CNP). METHODS Gene transfer efficiency and optimal virus concentration were determined using Ad.LacZ on porcine jugular veins in vivo (N= 2). Next, in 14 pigs, arteriovenous grafts were implanted bilaterally between the carotid artery and the jugular vein, followed local venous transduction with Ad.CNP (right) and Ad.mock (left). Transduction efficiency of Ad.CNP was evaluated by reverse transcription-polymerase chain reaction (RT-PCR) and cyclic guanosine monophosphate (cGMP) measurements (N= 2). Fourteen days after gene transfer, arteriovenous grafts were excised for histologic analysis (N= 12). RESULTS Ad.LacZ transduction (1 x 10E10 IU) of porcine veins resulted in evident expression of beta-galactosidase, mainly in the adventitia. At termination, intima/media ratio was decreased by 37% in CNP-treated veins, predominantly due to medial thickening (Ad.CNP 3.1 +/- 0.6 mm(2) vs. Ad.mock 1.70 +/- 0.3 mm(2); P < 0.01) rather than decreased intimal hyperplasia (NS). Adventitial delivery of CNP resulted in increased external elastic lamina (EEL) (Ad.CNP 11.8 +/- 1.4 mm vs. Ad.mock 9.4 +/- 1.0 mm; P= 0.04) and luminal area (Ad.CNP 10.7 +/- 1.4 mm(2) vs. Ad.mock 8.8 +/- 1.7 mm(2); P= 0.05) at the venous anastomosis. CONCLUSION Overexpression of CNP enhances venous medial thickening and increases outward remodeling in the outflow tract of porcine arteriovenous grafts. These findings underscore the potential of local gene-therapeutic interventions in preventing luminal narrowing at the outflow tract of hemodialysis grafts.
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Affiliation(s)
- Joris I Rotmans
- Department of Vascular Medicine, Academic Medical Center, Amsterdam, The Netherlands
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19
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Connolly EM, Kelly CJ, Chen G, O'grady T, Kay E, Leahy A, Bouchier-Hayes DJ. Pharmacological induction of HSP27 attenuates intimal hyperplasia in vivo. Eur J Vasc Endovasc Surg 2003; 25:40-7. [PMID: 12525810 DOI: 10.1053/ejvs.2002.1793] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVES intimal hyperplasia (IH) is a major cause of re-stenosis post-vascular intervention. Induction of heat shock proteins (HSPs), by thermal pre-conditioning, reduces IH. Our aim was to investigate the effect of the pharmacological HSP inducer herbimycin A on IH in the rat carotid balloon injury model. MATERIALS AND METHODS thirty male Sprague-Dawley rats were randomized into three groups. All groups underwent balloon injury to the left carotid artery. Stress proteins were induced 18 h pre-operatively by heat shock or herbimycin A. Two weeks post-operatively, animals were sacrificed and carotid intima/media area ratio (I/M ratio) calculated using computerized planimetry. Neo-intimal proliferation was assessed immunohistochemically with PCNA (proliferating cell nuclear antigen). Western blot and immunohistochemistry for arterial HSP70 and HSP27 were performed. RESULTS heat stress and herbimycin significantly reduced the I/M ratio (p < 0.05 vs balloon injury alone). Neo-intimal proliferation was significantly reduced in the heat stress and herbimycin groups (p < 0.05 vs balloon injury alone). Heat stress induced arterial HSP70 and HSP27. Herbimycin A increased arterial HSP27. CONCLUSION herbimycin A significantly attenuates IH after balloon injury. HSP27 may be the HSP involved in mediating this response. Pharmacological inducers of HSPs may have a therapeutic role to play in preventing re-stenosis post-vascular intervention.
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Affiliation(s)
- E M Connolly
- Departments of Surgery and Pathology, Education and Research Center, Royal College of Surgeons in Ireland, Beaumont Hospital, Beaumont Rd, Dublin 9, Ireland
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20
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Kibbe MR, Li J, Nie S, Choi BM, Kovesdi I, Lizonova A, Billiar TR, Tzeng E. Potentiation of nitric oxide-induced apoptosis in p53-/- vascular smooth muscle cells. Am J Physiol Cell Physiol 2002; 282:C625-34. [PMID: 11832348 DOI: 10.1152/ajpcell.00119.2001] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The functional role of p53 in nitric oxide (NO)-mediated vascular smooth muscle cell (VSMC) apoptosis remains unknown. In this study, VSMC from p53-/- and p53+/+ murine aortas were exposed to exogenous or endogenous sources of NO. Unexpectedly, p53-/- VSMC were much more sensitive to the proapoptotic effects of NO than were p53+/+ VSMC. Furthermore, this paradox appeared to be specific to NO, because other proapoptotic agents did not demonstrate this differential effect on p53-/- cells. NO-induced apoptosis in p53-/- VSMC occurred independently of cGMP generation. However, mitogen-activated protein kinase (MAPK) pathways appeared to play a significant role. Treatment of the p53-/- VSMC with S-nitroso-N-acetylpenicillamine resulted in a marked activation of p38 MAPK and, to a lesser extent, of c-Jun NH(2)-terminal kinase, mitogen-activated protein kinase kinase (MEK) 1/2, and p42/44 (extracellular signal-regulated kinase, ERK). Furthermore, basal activity of the MEK-p42/44 (ERK) pathway was increased in the p53+/+ VSMC. Inhibition of p38 MAPK with SB-203580 or of MEK1/2 with PD-98059 blocked NO-induced apoptosis. Therefore, p53 may protect VSMC against NO-mediated apoptosis, in part, through differential regulation of MAPK pathways.
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Affiliation(s)
- Melina R Kibbe
- Department of Surgery, University of Pittsburgh, 677 Scaife Hall, Pittsburgh, PA 15261, USA.
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21
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Sartore S, Chiavegato A, Faggin E, Franch R, Puato M, Ausoni S, Pauletto P. Contribution of adventitial fibroblasts to neointima formation and vascular remodeling: from innocent bystander to active participant. Circ Res 2001; 89:1111-21. [PMID: 11739275 DOI: 10.1161/hh2401.100844] [Citation(s) in RCA: 347] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The adventitial layer surrounding the blood vessels has long been exclusively considered a supporting tissue the main function of which is to provide adequate nourishment to the muscle layers of tunica media. Although functionally interconnected, the adventitial and medial layers are structurally interfaced at the external elastic lamina level, clearly distinguishable at the maturational phase of vascular morphogenesis. Over the last few years the "passive" role that the adventitia seemed to play in experimental and spontaneous vascular pathologies involving proliferation, migration, differentiation, and apoptosis of vascular smooth muscle cells (VSMCs) has been questioned. It has been demonstrated that fibroblasts from the adventitia display an important partnership with the resident medial VSMCs in terms of phenotypic conversion, proliferation, apoptotic, and migratory properties the result of which is neointima formation and vascular remodeling. This article is an attempt at reviewing the major themes and more recent findings dealing with the phenotypic conversion process that leads adventitial "passive" (static) fibroblasts to become "activated" (mobile) myofibroblasts. This event shows some facets in common with vascular morphogenesis, ie, the process of recruitment, incorporation, and phenotypic conversion of cells surrounding the primitive endothelial tube in the definitive vessel wall. We hypothesize that during the response to vascular injuries in the adult, "activation" of adventitial fibroblasts is, at least in part, reminiscent of a developmental program that also invests, although with distinct spatiotemporal features, medial VSMCs.
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Affiliation(s)
- S Sartore
- Department of Biomedical Sciences, National Research Council Unit for Muscle Biology, University of Padua, Italy
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22
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Shi Y, Patel S, Davenpeck KL, Niculescu R, Rodriguez E, Magno MG, Ormont ML, Mannion JD, Zalewski A. Oxidative Stress and Lipid Retention in Vascular Grafts. Circulation 2001; 103:2408-13. [PMID: 11352892 DOI: 10.1161/01.cir.103.19.2408] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background
—Because saphenous vein grafts (SVGs) exhibit greater cellular heterogeneity and worse clinical outcomes than arterial grafts (AGs), we examined oxidative stress and lipid retention in different vascular conduits.
Methods and Results
—In a porcine model of graft interposition into carotid artery, superoxide anion (·O
2
−
) was measured at 2 weeks after surgery. SVGs demonstrated increased ·O
2
−
production compared with AGs (SOD-inhibitable nitro blue tetrazolium reduction,
P
<0.01). The NAD(P)H oxidase inhibitor diphenyleneiodonium (
P
<0.01) abolished SVG-derived ·O
2
−
, whereas the inhibitors of other pro-oxidant enzymes were ineffective. The change in oxidative stress was also reflected by lower activity of the endogenous antioxidant superoxide dismutase in SVGs than in AGs (
P
<0.001). SVG remodeling was associated with increased synthesis of sulfated glycosaminoglycans and augmented expression of a core protein, versican. These changes were accompanied by SVGs retaining significantly more
125
I-labeled LDL than AGs ex vivo (
P
<0.001). In hyperlipemic animals, lipid accumulation and oxidized epitopes were preferentially noted in the intima of SVGs at 1 month after surgery.
Conclusions
—This study demonstrated significant differences in the biology of SVGs and AGs. SVGs exhibited higher oxidative stress, LDL accumulation, and the presence of oxidized epitopes. These findings suggest that proatherogenic changes in SVGs may commence early after surgical revascularization.
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Affiliation(s)
- Y Shi
- Cardiovascular Research Center, Departments of Medicine, Thomas Jefferson University, Philadelphia, PA, USA
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23
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Moore MM, Goldman J, Patel AR, Chien S, Liu SQ. Role of tensile stress and strain in the induction of cell death in experimental vein grafts. J Biomech 2001; 34:289-97. [PMID: 11182119 DOI: 10.1016/s0021-9290(00)00217-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Tensile stress and strain are known to induce vascular cell proliferation, a process that is physiologically counterbalanced by cell death. Here we investigate whether tensile stress and strain regulate vascular-cell death by using an end-to-end anastomosed rat vein graft model. In such a model, the circumferential tensile stress in the graft wall was increased by approximately 140 times immediately after surgery compared with that in the venous wall. This change was associated with an increase in the percentage of TUNEL-positive cells at 1, 6, 24, 120, 240, and 720h with two distinct peaks at 1 and 24h (10.1+/-3.5 and 14.4+/-3.2%, respectively) compared with that in control jugular veins (0.4+/-0.5 and 0.5+/-0.5% at 1 and 24h, respectively). When tensile stress and strain in the vein graft wall were reduced by using a biomechanical engineering approach, the rate of cell death was reduced significantly (3.6+/-1.1 and 1.6+/-0.5% at 1 and 24h, respectively). Furthermore, DEVD-CHO, a tetrapeptide aldehyde that inhibits the activity of caspase 3, significantly suppressed this event. These results suggest that a step increase in tensile stress and strain in experimental vein grafts induces rapid cell death, which is possibly mediated by cell death signaling mechanisms.
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Affiliation(s)
- M M Moore
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3107, USA
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24
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Ishida M, Komori K, Yonemitsu Y, Taguchi K, Onohara T, Sugimachi K. Immunohistochemical phenotypic alterations of rabbit autologous vein grafts implanted under arterial circulation with or without poor distal runoff-implications of vein graft remodeling. Atherosclerosis 2001; 154:345-54. [PMID: 11166767 DOI: 10.1016/s0021-9150(00)00498-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Although intimal hyperplasia is a major cause limiting the long-term patency of the vein grafts, its precise mechanisms, including the effect of poor runoff, has not yet been well characterized. We thus designed the present study to try to determine the effect of poor runoff arterial flow to the phenotypic alterations of the graft wall by immnohistochemistry using anti-intermediate filaments (alpha-SM actin, desmin, and vimentin) and anti-myosin heavy chain (SM1, SM2, and SMemb) specific antibodies. Vein grafts implanted under the poor runoff hind limb of rabbits showed enhanced intimal hyperplasia, however, no apparent difference in the cytoskeleton expression, including intermediate filaments and MHC, between two groups until 4 weeks. Interestingly, six of eight vein grafts at 2 weeks after implantation in both groups showed the accumulations of perivascular fibroblast-like phenotype (negative for SM1, alpha-SM actin, and desmin) in some parts of the outer neointima, whereas the inner neointima at 2 weeks and the whole neointima at 4 weeks were mainly occupied by a smooth muscle phenotype (positive for these three). Although the cellular origin of these cells is still unknown, these results suggest that the migration of non-muscle mesenchymal cells is involved in the neointima and thus may provide a clue for better understanding vein graft remodeling.
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Affiliation(s)
- M Ishida
- Department of Surgery II, Faculty of Medicine, Kyushu University, 3-1-1 Maidashi, 812-8582, Higashi-ku Fukuoka, Japan
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25
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Rodriguez E, Lambert EH, Magno MG, Mannion JD. Contractile smooth muscle cell apoptosis early after saphenous vein grafting. Ann Thorac Surg 2000; 70:1145-53. [PMID: 11081860 DOI: 10.1016/s0003-4975(00)01768-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
BACKGROUND The media of saphenous veins is composed of two cell populations: smooth muscle (SMC) and non-smooth muscle (NSMC) cells. Previous studies demonstrate a loss of SMCs by 3 days after grafting, despite an increase in cell proliferation. The purpose of this study is to determine the rates of apoptotic cell death versus cell proliferation for the two major cell populations of the media. METHODS Veins (six/time point) were examined at 0.5, 1, 2, 4, 8, 24, and 48 hours after grafting in crossbred pigs. Terminal transferase-mediated dUTP nick end labeling (TUNEL) and proliferating cell nuclear antigen (PCNA) stains were used to assess apoptosis and proliferation. Apoptosis was also corroborated with confocal and electron microscopy. RESULTS Apoptosis was high in both cell populations: at 8 hours, SMC and NSMC apoptosis peaked at 14.5% +/- 3.5% and 49.9% +/- 7.8%, respectively. In contrast, cell proliferation was different between the two populations. SMC proliferation was low at all time points, whereas NSMC proliferation rose to 22% +/- 5.4% by 48 hours. CONCLUSIONS Medial SMCs are removed through apoptosis and appear to be replaced by fibrous tissue (NSMCs) early after vein grafting. This reciprocal change between the medial SMC and NSMC populations may contribute to late vein graft degeneration.
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Affiliation(s)
- E Rodriguez
- Department of Surgery, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania, USA
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26
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Leville CD, Osipov VO, Jean-Claude JM, Seabrook GR, Towne JB, Cambria RA. All-trans-retinoic acid decreases cell proliferation and increases apoptosis in an animal model of vein bypass grafting. Surgery 2000; 128:178-84. [PMID: 10922989 DOI: 10.1067/msy.2000.107371] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BACKGROUND We have previously demonstrated a decrease in intimal hyperplasia in vein bypass grafts from animals treated with all-trans-retinoic acid (atRA). The purpose of this study was to examine the effect of atRA on proliferation and apoptosis rates in healing vein bypass grafts. METHODS Interposition jugular vein bypass grafts were placed in the carotid artery of 30 New Zealand white rabbits. Animals received either atRA (10 mg/kg/d) or vehicle (corn oil) for a period of 2 weeks. Animals were killed at 3, 7, or 28 days after graft placement after having received 3 doses of 5-bromo-2'-¿Deoxyuridine (BRDU, 35 Mg/KG). Animals Were Perfusion Fixed, And Vein Grafts Were Prepared For Immunohistochemistry By Using Antibodies To Brdu, Proliferating Cell Nuclear Antigen, And Bcl-XL. Apoptosis Was Measured By Using The Tunel Assay. Histologic Sections Were Analyzed By A Pathologist Blinded To The Study, And An Index Of Positively Stained Cells Was Generated For Each Layer Of The Vein Graft Wall. RESULTS All-trans-retinoic acid reduced the proliferation index in the neointima of vein grafts during the first week after surgery. Apoptotic rates were higher in the intima of vein grafts from animals treated with atRA, which could not be explained by changes in bcl-xl expression. No differences were noted in the media or adventitia between the groups. CONCLUSIONS atRA decreased cell proliferation and increased apoptosis in the intima of healing vein bypass grafts. These effects contribute to decreased intimal hyperplasia, which has been previously noted.
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Affiliation(s)
- C D Leville
- Division of Vascular Surgery and the Department of Pathology, Medical College of Wisconsin, Milwaukee, USA
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27
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Meguro T, Nakashima H, Kawada S, Tokunaga K, Ohmoto T. Effect of External Stenting and Systemic Hypertension on Intimal Hyperplasia in Rat Vein Grafts. Neurosurgery 2000. [DOI: 10.1227/00006123-200004000-00036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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28
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Meguro T, Nakashima H, Kawada S, Tokunaga K, Ohmoto T. Effect of external stenting and systemic hypertension on intimal hyperplasia in rat vein grafts. Neurosurgery 2000; 46:963-9; discussion 969-70. [PMID: 10764272 DOI: 10.1097/00006123-200004000-00036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
OBJECTIVE Overdistention of vein grafts in arterial circulation and systemic hypertension are thought to be influential risk factors contributing to vein graft failures. This study tested the effects of external stenting in preventing systemic hypertension and overdistention of the rat vein graft in the long term. METHODS Jugular vein grafts were interposed into the carotid artery of normotensive (n = 39) and two-kidney, one-clip hypertensive (n = 30) rats. Jugular vein grafts wrapped with 1.5-mm-diameter polyester stents were used in normotensive (n = 26) and hypertensive (n = 25) rats. The vein grafts were harvested at 1, 2, 4, 8, 12, and 24 weeks after the grafting procedure. The neointimal area and wall thickness were measured by computerized planimetry, and Ki-67 immunohistochemistry was used to detect replicative smooth muscle cells in the graft wall. RESULTS In each group, intimal hyperplasia was apparent at 1 week and increased gradually to 24 weeks. The number of Ki-67-positive cells was most increased at 2 weeks after the grafting procedure and gradually decreased thereafter. The numbers of Ki-67-positive cells and the extent of intimal hyperplasia were not significantly different between normotensive and hypertensive rats. Both neointima formation and cell proliferation in the graft wall were significantly reduced by external stenting as compared with the results with unstented grafts. CONCLUSION Systemic hypertension by itself is not a risk factor for intimal hyperplasia and experimental vein graft failure in the long term. External stenting is effective against intimal hyperplasia, and it is possible to reduce the subsequent atherosclerotic change of the vein graft wall and improve the long-term patency of the vein graft with external stenting.
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Affiliation(s)
- T Meguro
- Department of Neurological Surgery, Okayama University Medical School, Japan
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