PHARMACOLOGICAL CONTROL OF INTIMAL HYPERPLASIA IN SMALL-DIAMETER POLYTETRAFLUOROETHYLENE GRAFTS - AN EXPERIMENTAL-STUDY

Objective. The efficacy of a postoperative treatment with Low molecula r weight heparin (LIMWH) vs Ticlopidine in controlling early thrombosi s, intimal hyperplasia and growth of true endothelial cells in small p rosthetic expanded polytetrafluoroethylene (ePTFE) grafts (4 mm) inter posed in the carotid artery of sheep has been evaluated. Experimental design. Thirty animals were randomized into three different groups: co ntrol group (CTRL); ticlopidine hydrochloride (TICL) 250 mg/b.d. by mo nth for 4 weeks from day 1; LMWH 3,075 IU AXa s.c. preoperatively and once a day for the same period. Results. Complete thrombosis of the gr aft occurred in 7 sheep in the CTRL group and 5 in the TICL group whil e 2 partial thrombosis were observed in the LMWH group (n.s.). In all the evaluable cases, hyperplasia was observed in both anastomotic area s and did not involve the middle portion of the graft. The mean+/-SD i ntimal thickness was 603+/-20 micron in the CTRL group, 356+/-10 in th e TICL group and 152+/-17 in the LMWH group (p<0.001) compared to the 60+/-12 of the normal intima. True endothlial cells were found mainly in the LMWH group close to the arterial anastomosis. Conclusions. The postoperative use of LMWH seems to inhibit intimal hyperplasia, with i nteresting results also on patency and cellular coverage. Further stud ies are necessary to support this promising trend.