Does 111indium-platelet deposition predict patency in prosthetic arterial grafts?

Abstract

Abstract The relationship between the rate of 111In-platelet deposition on vascular grafts and subsequent thrombosis has been examined in patients undergoing femoropopliteal by-pass. Sixty-seven patients undergoing femoropopliteal by-pass using vein, Dacron or PTFE were randomized to aspirin plus dipyridamole (ASA/DPM) or placebo. Autologous 111In-platelets were injected in the second postoperative week and Thrombogenicity Index (TI) calculated as the mean daily rise in the ratio of radioactivity graft/contralateral thigh. Graft patency was assessed to 1 year. Mean (+ s.e.m.) TI at 1 week in 21 grafts that occluded within 12 months was 0·19 ± 0·018 compared with 0·07 ± 0·009 in the 38 that remained patient (P < 0·001). Grafts with a TI less or greater than the median had a 90 per cent or 39 per cent cumulative 1-year patency, respectively (P < 0·001). In the prosthetic grafts ASA/DPM reduced mean TI from 0·17 ± 0·02 to 0·11 ± 0·01 (P < 0·02) and enhanced 1-year patency from 36 to 67 per cent (P < 0·05). Following femoropopliteal by-pass TI related to subsequent graft patency. Radiolabelled platelet deposition therefore provides a guide as to how new materials or antithrombotic drugs may influence clinical graft thrombosis. Platelet inhibition reduced both graft thrombogenicity and subsequent occlusion.