Effect Of Postoperative Irradiation On Neointima Of Prosthetic Vascular Graft After Prosthetic Vessel Replacement In Canine

Objective To observe the effect of postoperative irradiation with tumor cure dose on the patency rate, the neointima proliferation of vascular graft, as well as covering of vascular endothelial cell to the neointima after prosthetic vessel replacement.Methods 20 mistus dogs were divided into 4 groups averagely, 2 were experiment groups and 2 were control groups.Abodominal aorta replacement with ePTFE vascular graft was carried out in each group. 2 weeks after the surgery, external segmental irradiation with a total dose of 35 Gy was done to dogs in experiment groups and nothing to the control groups. The ePTFE vascular graft was harvested 4 weeks and 8 weeks after the surgery respectively, observing the patent condition of vascular graft. With the technique of H-E staining, immunohistochemistry and computer skills, neointimal thickness was measured and covering of vascular endothelial cell to neointima was evaluated.Results1,1 case in radiotherapy group had thrombosis of prosthetic vessel after irradiation, and 1 case in control group had vascular thrombosis, the patency rates in radiotherapy group and control group were both 90%.2,4 weeks after operation, the neointima of vascular graft formed completely, and the intimal thicknesses in both radiotherapy group and control group had no statistically difference(p>0.05), and the coverage of vascular endothelial cell was incomplete in either control group or radiotherapy group. 8 weeks after operation, intact neointima had formed in both radiotherapy and control group, the vascular endothelial cell coverage was complete in both group, and the intimal thickness was significantly smaller in radiotherapy group than in control group(p<0.05). The intimal thickness at the middle of vascular graft was thinner than the position near the anastomosis(p<0.05), The neointima near the distal anastomosis was statistically thicker than that near the proximal anastomosis (p<0.05).3,4 weeks after operation, the PCNA proliferation of neointima in vascular graft had no statistical difference between radiotherapy group and control group. 8 weeks after operation, the PCNA proliferation in radiotherapy was less than control group(p<0.05). The PCNA proliferation at the middle of vascular graft was less than the place near the anastomosis(p<0.05), and that near the distal anastomosis was more than near the proximal anastomosis(p<0.05).Conclusions1,Postoperative external segmental radiotherapy at the dose of 35 Gy does not affect the patency rate of prosthetic vascular graft.2,Postoperative external segmental radiotherapy at the dose of 35 Gy can inhibit the neointima proliferation and PCNA expression.3,Postoperative external segmental radiotherapy at the dose of 35 Gy dosesn't affect the vascular endothelial cell coverage rate obviously.4,This study helps judge whether a patient received tumor eradication accompanied with prosthetic vascular replacement can receive postoperative radiotherapy, and it has certain reference value.