The Effect Of Post-operative Irradiation External Beam Radiation On The EPTFE Prosthesis-vascular Graft Anastomosis After Vein Prosthetic Vessel Replacement In Canine

Objective To observe the effect of post-operative irradiation with tumor cure dose on the neointima proliferation of vascular graft anastomosis, as well as covering of vascular endothelial cell to the neointima after inferior vena cava prosthetic vessel replacement.Methods 16 dog's were randomly divided into 2 groups including the radiotherapy group and the control group. Inferior vena cava replacement with a 6-mm ePTFE vascular graft was carried out in each group. The radiotherapy group was irradiated with a dose of external radiation (35Gy) on the ePTFE vascular and the distal end-to-side anastomosis at 2 weeks after surgery while the other not. All the dogs were sacrificed at 8 weeks after operation for histological and immunohistochemical examination of the neointima of the venous prosthetic vascular graft anastomosis and observe the coverage of vascular endothelial cell of the venous prosthetic vascular graft anastomosis.Results All dogs of the control group survived. 8 cases of radiotherapy group and 6 cases of control group patency of artificial blood vessels are good. Apart from 2 cases in the control group were infection, the radiotherapy group artificial vascular patency rate is 8/8, the control group patency rate is 6 / 8. Histological examination shows that intact neointima of anastomosis had formed completely in 8 cases in the radiotherapy group and 6 cases in the control group. The thickness of neointimal of vascular prosthesis anastomosis was measured. The intimal thickness was significantly smaller in radiotherapy group than in control group(p<0.01). The neointima proliferation near the proximal anastomosis was significantly obvious than the far anastomosis of the vascular graft (p<0.01). The PCNA proliferation in radiotherapy group was less than control group (p<0.05). In the control group, the PCNA proliferation near the proximal anastomosis was significantly more than near the distal anastomosis (p<0.01). The coloration of CD34 showed that the vascular endothelial cell coverage was complete in both groups.Conclusions High dose of external beam(35 Gy) result in marked histological changes at the prosthesis-venous anastomosis and the irradiation-induced histological changes include fibrosis and necrosis at the prosthesis-venous anastomosis, fibrosis of the media and necrosis of the adventitia. No disunion, rupture and aneurysm was found at the prosthesis-venous anastomosis in out study. The irradiation do not increase the risk of thrombosis at the prosthesis graft. The beam showed inhibition of the intima hyperplasia 6 weeks after irradiation, however, the long-term effect of the irradiation on the prosthesis-venous anastomosis awaits further investigation.