PLACEBO-CONTROLLED TRIAL OF ENTERIC-COATED ASPIRIN IN CORONARY-BYPASS GRAFT PATIENTS - EFFECT ON GRAFT PATENCY

Objective: To determine whether slow-release enteric coated aspirin (100 mg daily), commenced before operation, improves the patency of saphenous vein (SV) coronary artery bypass grafts at six months. Design and setting: Double-blind, randomised, placebo-controlled study at a teaching hospital. Results: One hundred and forty patients were randomly allocated to receive enteric coated aspirin or matching placebo. Similar groups of 50 (aspirin) and 52 (placebo) subjects completed the six months follow-up and had an angiogram to assess patency. Five patients treated with aspirin and nine who received placebo had at least one occluded SV graft; the distal ends of 6 of 128 SV grafts in aspirin-treated patients (4.7%) and 13 of 145 SV grafts in patients in the placebo group (9.0%) were occluded - the difference was not significant. An arterial graft was occluded in one other patient in each group (3% of arterial grafts). There was more postoperative blood loss, on average, in patients treated with aspirin, but the difference was not significant. Only one patient was withdrawn from long-term therapy because of possible gastrointestinal symptoms; most withdrawals from the trial were necessitated by commencement of aspirin or non-steroidal anti-inflammatory therapy for musculo-skeletal disorders. Conclusions: The coronary bypass graft occlusion rate six months after surgery was low, and was lower on average in aspirin treated subjects but not significantly so. Long-term treatment with low-dose aspirin is recommended unless contraindicated.