INTIMAL HYPERPLASIA FOLLOWING THROMBECTOMY VERSUS THROMBOLYSIS IN OCCLUDED VEIN GRAFTS

Although the histologic effects of balloon catheter thromboembolectomy in arteries are well described, little is known about its effects on arterialized vein grafts. A chronic canine model was used to compare t he intimal hyperplasia that develops following balloon catheter thromb ectomy versus thrombolytic therapy when each treatment was used to ope n experimentally occluded reversed autogenous vein grafts. Eleven of 1 2 dogs survived to the time of graft thrombosis and treatment. Ten gra fts in one group of animals were treated with shear force-controlled b alloon catheter thrombectomy, and eleven grafts in another group of an imals were treated with infusion of urokinase (average 355, 833 IU/gra ft). Explantation and histologic evaluation was performed 5 weeks afte r treatment. Data were evaluated at comparable anatomic locations. The se studies demonstrated the development of intimal hyperplasia in both groups with no statistically significant differences in the intimal t hickening between the two treatment groups. It is hypothesized that ve ssel wall damage occurs at the time of thrombosis with the adherence o f thrombus to the walt, and that this may be as important in producing intimal hyperplasia as the effects of carefully performed balloon thr ombectomy or lytic therapy.