Improved aortocoronary bypass patency by low-dose aspirin (100 mg daily). Effects on platelet aggregation and thromboxane formation.
Prevention of aortocoronary bypass occlusion by aspirin (ASA, 1 X 100 mg per day) was studied in a prospective double-blind trial of 83 patients. 60 (72%) were randomly allocated to ASA or placebo starting 24 h after operation. 90% of grafts in the ASA group and 68% in the placebo group were patent at four months. At least one anastomosis was occluded in 62% of the patients on placebo and in 27% of those on aspirin. Ventricular arrhythmias increased after surgery in more patients on placebo (12/18) than in patients on ASA (5/17). Platelet thromboxane formation on collagen tested before operation was significantly higher in patients in whom bypass occlusion developed (occlusion: 40 +/- 19, no occlusion: 25 +/- 13 ng/ml). A 100 mg dose of ASA per day effectively blocked platelet thromboxane formation and thromboxane-supported aggregation on collagen and was safe in the postoperative phase. No side effects were reported throughout the trial. The reduced toxicity with full efficacy favours a low and infrequent dosage of aspirin.
D001241:Aspirin / Q000008:administration & dosage / Q000494:pharmacology*; D001792:Blood Platelets / Q000378:metabolism; D002986:Clinical Trials as Topic; D001026:Coronary Artery Bypass; D004311:Double-Blind Method; D005260:Female; D006085:Graft Survival; D006801:Humans; D008297:Male; D008875:Middle Aged; D010974:Platelet Aggregation / Q000187:drug effects*; D011446:Prospective Studies; D011897:Random Allocation; D013931:Thromboxanes / Q000096:biosynthesis*
D013931:Thromboxanes; D001241:Aspirin