Aggressive approach to late thrombosis of bovine heterografts.

Between January, 1977 and December, 1978, 26 patients presented with delayed thrombosis of bovine heterografts inserted for chronic hemodialysis. Time of presentation ranged from 2-29 months (mean 8.8 months) after insertion. At the time of presentation eight patients were not considered candidates for thrombectomy due to associated infection or physician preference. The remaining eighteen patients underwent thrombectomy, 13 of whom required concomitant revision of the graft (patch angioplasty at the venous anastomosis (6), dilatation (1), resection of intimal hyperplasia (2), resection of stenotic segment with interposition graft (2), resection of false aneurysm (1) and patch graft to mid graft stenosis (1)). Six grafts failed from eight days to seven months after thrombectomy and could not be salvaged. Two grafts functioned until death at three and four months after thrombectomy and the remaining ten grafts remain patent from 4-24 months (mean 13.1 months) after thrombectomy. Critical to success of thrombectomy is an incision over the venous limb with calibration of the venous anastomosis and patch angioplasty when indicated. At completion of thrombectomy arteriograms are mandatory to defect residual thrombosis, defects in the graft and adequacy of venous runoff. This standardized approach has resulted in a significant prolongation of bovine heterograft survival.