Suppression by antithrombotic agents of pseudointimal hyperplasia of polytetrafluoroethylene graft implanted into venous system.

The lumen of the polytetrafluoroethylene graft (PTFE) implanted into a rabbit inferior vena cava (IVC) was markedly narrowed by 4 weeks after grafting. This was due to initial thrombosis on the luminal surface of the graft, which was followed by pseudointimal hyperplasia (PIH). To elucidate the role of the initial thrombosis in subsequent PIH, the effect of ticlopidine (T) and/or warfarin (W) on PIH was studied in an animal model. A PTFE tube graft was implanted into a rabbit IVC. Twenty eight rabbits were randomly assigned to the following experimental groups. Eight rabbits without antithrombotic agents were observed for 2 weeks (A, n = 4) and 4 weeks (B, n = 4) after grafting. T (100 mg/kg/day) and W (0.33 mg/kg/day) were orally administered for 4 weeks to group C (n = 4) and group D (n = 4), respectively. A combination of a half dose of T and W ((T + W)/2) was given for 2 weeks (E, n = 4) and 4 weeks (F, n = 4) after grafting. Four rabbits in group G received the combination of T and W for the first 2 weeks and were observed for an additional 2 weeks without medication. All the grafts were patent at time of harvest. The dry weight of the intraluminal deposit (DW) was determined as an indicator of PIH (A:35 +/- 1 mg/graft, B:40 +/- 8, C:22 +/- 3, D:22 +/- 3, E:14 +/- 2, F:15 +/- 3, G:23 +/- 2). Administration of T or W was equally effective in reducing DW and (T+W)/2 was more effective than a single agent.(ABSTRACT TRUNCATED AT 250 WORDS)