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

Objective: To determine whether slow-release enteric coated aspirin (1 00 mg daily), commenced before operation, improves the patency of saph enous vein (SV) coronary artery bypass grafts at six months. Design an d setting: Double-blind, randomised, placebo-controlled study at a tea ching hospital. Results: One hundred and forty patients were randomly allocated to receive enteric coated aspirin or matching placebo. Simil ar 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 o ccluded SV graft; the distal ends of 6 of 128 SV grafts in aspirin-tre ated patients (4.7%) and 13 of 145 SV grafts in patients in the placeb o 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 signific ant. Only one patient was withdrawn from long-term therapy because of possible gastrointestinal symptoms; most withdrawals from the trial we re necessitated by commencement of aspirin or non-steroidal anti-infla mmatory therapy for musculo-skeletal disorders. Conclusions: The coron ary 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 c ontraindicated.