Low-dose and high-dose acetylsalicylic acid for patients undergoing carotid endarterectomy: a randomised controlled trial

carotid stenosis, but benefits are lessened by perioperative surgical risk. Acetylsalicylic acid lowers the risk of stroke in patients who have experi enced transient ischaemic attack and stroke. We investigated appropriate do ses and the role of acetylsalicylic acid in patients undergoing carotid end arterectomy. Methods In a randomised, double-blind, controlled trial, 2849 patients sche duled for endarterectomy were randomly assigned 81 mg (n=709), 325 mg (n=70 8), 650 mg (n=715), or 1300 mg (n=717) acetylsalicylic acid daily, started before surgery and continued for 3 months. We recorded occurrences of strok e, myocardial infarction, and death. We compared patients on the two higher doses of acetylsalicylic acid with patients on the two lower doses. Findings Surgery was cancelled in 45 patients, none were lost to follow-up by 30 days, and two were lost by 3 months. The combined rate of stroke, myo cardial infarction, and death was lower in the low-dose groups than in the high-dose groups at 30 days (5.4 vs 7.0%, p=0.07) and at 3 months (6.2 vs 8 .4%, p=0.03). In an efficacy analysis, which excluded patients taking 650 m g or more acetylsalicylic acid before randomisation, and patients randomise d within 1 day of surgery, combined rates were 3.7% and 8.2%, respectively, at 30 days (p=0.002) and 4.2% and 10.0% at 3 months (p=0.0002). Interpretation The risk of stroke, myocardial infarction, and death within 30 days and 3 months of endarterectomy is lower for patients laking 81 mg o r 325 mg acetylsalicylic acid daily than for those taking 650 mg or 1300 mg .