Microscopic and immunohistological studies on intimal hyperplasia of the arterially implanted autovein graft and its anastomosis in dogs

Abstract

The fate of intimal hyperplasia of arterially implanted autovein bypass grafts and their distal end-to-side anastomoses in dogs was studied microscopically and immunohistologically. The bypass grafting was done under conditions of abnormal blood flow and high peripheral resistance. Intimal hyperplasia of the graft first became evident 7 days after implantation and the thickness increased to about 500 microns 3 months or more after the implantation. The intimal hyperplasia was related to an active proliferation of smooth muscle cells which proved positive for alpha-smooth muscle actin staining. Moreover, it was more dominant at the toe and heel of the anastomosis and moderately apparent on the floor of the host artery. The constituent elements of the hyperplastic intima at the anastomosis were fibroblast-like cells and extracellular collagen fibers which were negative for alpha smooth muscle actin staining. This study revealed that the features of intimal hyperplasia at the distal anastomosis in autovein bypass grafting differed from those of the implanted autovein graft itself; the former being related to excessive proliferation of fibroblasts and collagen fibers while the latter displayed an active proliferation of smooth muscle cells.

Large animal model of vein grafts intimal hyperplasia: A systematic review

“…Different models were designed to study the development of IH. This included using femoral vein–femoral artery interposition in 23 studies ( in situ or reversed), 14,17,18,20,23–25,30,32–38,40,42,51,52,55,56,58,60 jugular vein–carotid artery interposition grafts in 12 studies, 12,16,19,29,31,41,46,49,50,54,57,59 jugular vein–femoral artery interposition graft in 7 studies, 6–9,11,39,48 cephalic vein–femoral artery interposition graft in 2 studies, 47,53 femoral vein–carotid interposition in 2 studies, 21,22 saphenous vein–femoral artery interposition model in 2 studies, 15,27 Jugular vein to both the carotid and femoral arteries in 1 study, 13 jugular vein to carotid artery and femoral vein to femoral artery in 1 study ( in situ or reversed), 26 and 1 study used different types of venous and arterial interposition models. 10 The saphenous vein end to side between the LAD and aorta was used in 2 studies, 43,45 and 2 studies utilized a femoropopliteal-saphenous vein end to the side model.…”

Pathophysiological features of intimal hyperplasia of the arterially implanted autovein graft and its anastomosis in dogs

“…Late occlusion in peripheral arterial reconstruction with an autogenous vein graft often occurs in cases of poor distal outflow, the cause being excessive intimal hyperplasia of the implanted autovein grafts and distal end-to-side anastomoses [10][11][12][13][14][15][16]. In the present study, pathophysiological features of intimal hyperplasia of the arterially implanted autovein grafts and their distal end-to-side anastomoses, which were implanted under conditions of poor distal outflow, were investigated using light and electron rmcroscopy and immunohistochemical staining.…”

“…In contrast, in cases of poor distal outflow, smooth muscle cell proliferation in the intimal hyperplasia was still in an active phase even at 6 months and longer after grafting. On the other hand, the neointima of the distal end-to-side anastomosis was proliferated at the toe, heel, and floor portions, and especially excessive at the toe portion [ 10,11,16]. Cells in the proliferated neointima at the toe portion of the distal anastomosis within 14 days after grafting were fibroblast-like cells and were diffusely labeled by BrdU.…”

“…However, late graft occlusion caused by progressive intimal hyperplasia of the vein graft and/or at the distal end-to-side anastomosis has occurred in about 30% of cases with poor distal outflow, Correspondence to: Tsutomu Kawabata, M.D., Second Department of Surgery, Faculty of Medicine, University of' the Ryukyus, 207 Uehara, Nishihara-cho, Okinawa 903-01, Japan 1-3 years after grafting [6][7][8][9]. Shrestha et al [10] pointed out that intimal hyperplasia of the implanted autovein graft was related to active proliferation of smooth muscle cells at the graft and of fibroblast-like cells at the distal end-to-side anastomosis. We have studied another group of dogs to obtain pathophysiological information on intimal hyperplasia of the vein graft and its distal end-to-side anastomosis in terms of microscopic examinations and immunohistochemical detection of 5-bromodeoxyuridine (BrdU) incorporated into the cells.…”

Long-Term Behavior of an Arterial Autograft: A New Role for Intimal Hyperplasia?

“…Histochemically, the cells of the intima had the charac teristics of smooth muscle cells [5] and were positive for a-actin labelling [24], In our model using immunohisto chemical techniques for electron microscopy, actin fibrils were found in the cells of the myointima.…”