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

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 less than 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 less than 0.001). In the prosthetic grafts ASA/DPM reduced mean TI from 0.17 +/- 0.02 to 0.11 +/- 0.01 (P less than 0.02) and enhanced 1-year patency from 36 to 67 per cent (P less than 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.

Antiplatelet Therapy in Peripheral Occlusive Arterial Disease

“…Intimal hyperplasia mediated by PDGF release from endothelial denudation at anastomoses is associated with increased platelet adhesion 1 . The clinical improvement in lower limb bypass patency associated with APT may be related to the inhibition of platelet‐mediated thrombosis and intimal hyperplasia 55–59 …”

Indium-111 platelet scintigraphy in vascular disease

“…In humans, i n f r a i n g~i n a l~~-~~ and aortic b i f u r c a t i~n~~?~~ grafts show significantly less platelet deposition with concomitant antiplatelet therapy. This occurs in both new26, [47][48][49] and matures6 grafts. Such therapy has no effect on platelet deposition in aortic aneurysms, even where positive scintigraphy confirms active platelet d e p o~i t i o n~~, although sulphinpyrazone may reduce deposition in some patients.…”

A Critical Analysis on the Impact of Antiplatelet Therapy in the Patency of Infrainguinal Bypass Grafts

“…The first meta-analysis published in 1994, [8] included 11 studies [9][10][11][12][13][14][15][16][17][18][19]. In these studies, allocation to antiplatelet therapy compared to placebo was associated with a proportional reduction of 38% (± 9%) in graft occlusion, which was highly significant [8].…”