Graft material and results of platelet inhibitor trials in peripheral arterial reconstructions: reappraisal of results from a meta‐analysis

Abstract

Aims To investigate the characteristics of published trials in order to establish the origin of the differing results obtained in trials of platelet inhibitors after peripheral bypass procedures. Methods Analysis of the information from 11 randomised, controlled trials of platelet inhibitors after peripheral bypass procedures published up until 1999 and involving 2302 patients undergoing peripheral bypass operations, 1250 of whom were treated with platelet inhibitors. Results There is a signi®cant treatment bene®t of platelet inhibitors on meta-analysis of the trials, but a signi®cant heterogeneity amongst the individual trial results. The proportion of patients in a trial with prosthetic grafts was a signi®cant factor in explaining the heterogeneity. Proportion of prosthetic grafts was associated with sample size and with the proportion of grafts above the knee, but these were not found to make an independent contribution to the heterogeneity observed. The platelet inhibitor regimen used, the severity of ischaemic symptoms and the proportion of smokers included were also not found to be important. Conclusions The improvement of graft patency by aspirin and related platelet inhibitors in clinical trials in peripheral bypass procedures can be attributed to an effect on patients with prosthetic grafts. There is little evidence that these agents prevent occlusion of vein grafts. The conclusion of an earlier meta-analysis that antiplatelet agents should be used for all bypasses is not supported.

Identification of factors predictive of lower extremity vein graft thrombosis

“…32,33 A third metaanalysis concluded that the improvement in graft patency seen with platelet inhibitors was attributed to an effect on synthetic grafts, and that no benefit was appreciated in vein grafts. 34 The Dutch Bypass Oral Anticoagulants or Aspirin Study Group recently concluded, on the basis of a prospective randomized trial, that aspirin was of benefit in the prevention of prosthetic but not autogenous graft occlusion. 35 The association of tibial distal anastomotic sites and an increased incidence of thrombosis is not surprising.…”

Antithrombotic Therapy for Peripheral Artery Occlusive Disease

“…The beneficial effect of antiplatelet therapy on prosthetic graft patency has been supported by a meta-analysis of all trials since 1999. 163 The Dutch BOA study (see previously) compared antiplatelet therapy with aspirin to VKA alone. 135 In the subgroup of 1,100 patients with prosthetic grafts, VKA was inferior to aspirin (hazard ratio 1.32, 95% CI 0.81-2.15).…”

Antithrombotic Strategies in Vascular Surgery: Evidence and Practice

“…The role of anticoagulation and platelet inhibitors for different bypass materials after infrainguinal surgery is well documented by several prospective randomised trials and meta-analyses. [16][17][18][19][20][21] In preventing prosthetic infra-inguinal bypass graft occlusions, low dose ASA is superior to vitamin K antagonists. Oral anticoagulation, on the other hand, does improve long-term patency rates for infrainguinal venous bypass grafts compared to ASA.…”