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Immediate postoperative aspirin improves vein graft patency early and late after coronary artery bypass graft
T P Gavaghan1, V Gebski, D W Baron
1Department of Cardiology and Cardiothoracic Surgery, St. Vincent's Hospital, Sydney, New South Wales, Australia.
Insights
Aspirin administered within 1 hour of coronary artery bypass grafting significantly reduces thrombotic graft occlusion at 1 week and 1 year. Early aspirin use improves graft patency and prevents late occlusion without increasing blood loss.
Area of Science:
- Cardiovascular Surgery
- Pharmacology
- Clinical Trials
Background:
- Thrombotic graft occlusion is a significant complication after coronary artery bypass grafting (CABG).
- The efficacy of aspirin in preventing graft occlusion is dose- and time-dependent.
- Optimal timing and dosage of aspirin for post-CABG graft patency require investigation.
Purpose of the Study:
- To assess the efficacy of early aspirin administration in preventing graft occlusion after CABG.
- To evaluate both early (1 week) and late (1 year) graft patency in patients receiving aspirin post-CABG.
- To compare aspirin's effects on graft patency, blood loss, and reoperation rates against a placebo.
Main Methods:
- Prospective, double-blind, randomized, placebo-controlled trial.
- Aspirin (324 mg daily) administered within 1 hour of CABG.
- Angiographic graft patency assessed at 1 week and 1 year post-CABG.
Main Results:
- Early vein graft occlusion rate: 1.6% on aspirin vs. 6.2% on placebo (p=0.004).
- Late graft occlusion rate (1 year): 5.8% on aspirin vs. 11.6% on placebo (p=0.01).
- No significant difference in 24-hour chest tube blood loss or red cell transfusion requirements between groups.
Conclusions:
- Immediate postoperative aspirin (324 mg) administration significantly improves early graft patency after CABG.
- Continued aspirin use protects against graft occlusion up to 1 year post-CABG.
- Aspirin was associated with a nonsignificant trend toward higher reoperation rates.
Background:
The efficacy of aspirin for prevention of thrombotic graft occlusion after coronary artery bypass grafting (CABG) depends both on the dosage and time window of administration. Early and late graft patency were therefore assessed in a prospective, double-blind, randomized, placebo-controlled trial of aspirin, 324 mg daily, given within 1 hour of CABG.
Methods And Results:
Angiographic graft patency was determined at 1 week (231 patients) and 1 year (219 patients) after CABG. The early vein graft occlusion rate was 1.6% on aspirin and 6.2% on placebo (p = 0.004), and late graft occlusion rate was 5.8% on continued aspirin and 11.6% on placebo (p = 0.01). New graft occlusion between 1 week and 1 year was less common in patients on aspirin than on placebo (4.3% versus 7.4%, p = 0.013). The protective effect of aspirin against occlusion persisted in most subgroups of graft type, graft flow, diameter of recipient artery, location of grafted artery, and endarterectomy. Mean chest tube blood loss for the first 24 hours was 571 ml for the aspirin group and 563 ml for the placebo group. Red cell transfusion requirements were 902 ml in the aspirin group and 934 ml in the placebo group (p = NS). The reoperation rate was 4.8% in the aspirin group and 1% in the placebo group (p = 0.1).
Conclusions:
Immediate postoperative administration of aspirin (324 mg) improves early graft patency and, with continued usage, protects against further occlusion up to 1 year after CABG. Postoperative blood loss was similar in the two groups; however, aspirin was associated with a nonsignificant higher rate of reoperation.