Animal Experimental Studing Of Cryoplasty For The Treatment Of Peripheral Arterial Disease

Objective:To investigate the establishment of an animal model of iliac artery stenosis.To compare the effect of balloon angioplasty and cryoplasty on iliac artery stenosis in dogs.To investigate the mechanism of cryoplasty.Methods:An animal model of iliac artery stenosis was established with surgical ligation and transfixion.The degree of iliac artery stenosis was assessed by digital subtraction angiography(DSA) immediately and after four weeks.Models were randomly devided into two groups: the iliac artery stenosis was intervented by cryoplasty in group A(n=8), and it was by balloon angioplasty in group B(n=8). The degree of iliac artery stenosis of two model groups was assessed by DSA immediately and two weeks after the angioplasties.Then all the dogs were executed for the target vascular.The target vasculars were havested for pathomorphology and immunhistochemistry observation.Results:Sixteen models of iliac artery stenosis were established by surgical ligation and transfixion method, and the success rate was 100%. DSA showed that artery disablity stenosis was (45±12.25)% in group A immediately after cryoplasty,and that was (38.75±12.17)% in group B after balloon angioplasty.There was no significant difference between them. The artery disablity stenosis of Group A was (48±17.47)% after two weeks,and there was no significant difference (t=-1.271,P=0.244)compared with angiography immediately; The artery disablity stenosis of Group B was (66.88±13.35)% after two weeks,and there was significant difference (t=-6.666,P<0.001)compared with angiography immediately. The degree of vascular stenosis in Group A was lighter than Group B(P <0.05). The pathological examination showed that artery intimal hyperplasia of Group A was lighter than Group B (P<0.01); and neointimal content of collagen of Group A was less than Group B (P<0.01). Immunohistochemical examination results suggested that MMP-2 expression in Group A was less than in Group B, There was significant difference (P <0.01) of TIMP-2 and MMP-2 expression in between the two groups. Conclusions:1. The animal model of iliac artery stenosis can be established successfully by surgical ligation and transfixion which can injury the intima and media of arterial wall.2.The cryoplasty can reduce the degradation of extracellular matrix of vascular,also can inhibit the migration and proliferation of VSMC and reduce collagen synthesis, So the neointima formation was significantly reduced and the iliac artery restenosis was mitigatory.3.The cryoplasty may be make for mitigation or prevention of restenosis .It may be a new therapeutic method for prevention restenosis after PTA. It shoud be better perspective.