A Prospective Randomized Study to Examine the Effect of Aspirin Plus Dipyridamole on the Patency of Prosthetic Femoro-Popliteal Grafts

When prosthetic materials are used in arterial reconstruction patency rates are less favourable due to the formation of platelet thrombus on the luminal surface. As platelet inhibitory drugs may reduce the rate of platelet accumula tion on such grafts, a randomised, double blind study has been undertaken to assess the effect of Aspirin and Dipyridamole on the patency of prosthetic fe moropopliteal bypass grafts. Drug or identical placebo therapy was started two days pre-operatively in 53 patients undergoing femoropopliteal bypass using either Dacron or Polytetrafluorethylene. Follow-up was for at least one year or until first occlusion, with patency assessed objectively. In the 28 patients on placebo cumulative patency by life table was 36% by 12 months compared to 67% on ASA/DPM (P < 0.05). In 37 patients with PTFE grafts, ASA/DPM en hanced one year patency from 50% to 80%. This drug combination therefore reduces prosthetic graft thrombosis in patients and must now be considered the standard against which new drugs should be compared.