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Danish very-low-dose aspirin after carotid endarterectomy trial
G Boysen1, P S Sørensen, M Juhler
1Department of Neurology, Rigshospitalet, Copenhagen, Denmark.
Insights
Very-low-dose aspirin did not significantly reduce the risk of major vascular events in patients after carotid endarterectomy. This antithrombotic therapy showed no significant benefit in preventing stroke or other cardiovascular outcomes in the study.
Area of Science:
- Cardiology
- Neurology
- Vascular Surgery
Background:
- Carotid endarterectomy is a procedure to prevent stroke.
- Antithrombotic agents like aspirin are commonly used to reduce thrombotic events.
- The optimal dose of aspirin for antithrombotic effect after carotid endarterectomy requires investigation.
Purpose of the Study:
- To evaluate the efficacy of very-low-dose aspirin as an antithrombotic agent in patients post-carotid endarterectomy.
- To determine if individually adjusted very-low-dose aspirin reduces the risk of major vascular events.
Main Methods:
- A blinded, randomized controlled trial involving 301 patients undergoing carotid endarterectomy.
- Patients were randomized to receive either aspirin (n=150) or placebo (n=151).
- Aspirin dosage was individually adjusted to achieve satisfactory platelet inhibition, with follow-up for an average of 25 months.
Main Results:
- Aspirin effectively inhibited platelet aggregation in most patients, with doses ranging from 50-100 mg/day.
- The placebo group showed minimal inhibition of platelet aggregation (1.2%).
- Aspirin demonstrated an 11% risk reduction for combined vascular events (TIA, stroke, MI, vascular death), but this was not statistically significant (p > 0.1).
Conclusions:
- Very-low-dose aspirin, even when adjusted for platelet inhibition, did not yield a statistically significant reduction in major vascular events after carotid endarterectomy.
- The study did not find evidence to support the routine use of very-low-dose aspirin for preventing thrombotic complications in this patient population.
Abstract:
The effect of very-low-dose aspirin as an antithrombotic agent was evaluated blindly in 301 patients who had recently undergone carotid endarterectomy. After randomization, 150 patients received aspirin and 151 received placebo. The two groups were comparable with regard to age, sex, blood pressure, previous cerebrovascular events, and smoking habits. The effect of the study medication on platelet aggregation was measured twice in each patient during the first 2 months and at each follow-up visit; the dose was individually adjusted. In 76% of the patients receiving aspirin, 50 mg/day gave satisfactory platelet inhibition, 13% needed 60 mg/day, 8% needed 70 mg/day, and 3% needed 100 mg/day. Platelet aggregation was found to be inhibited in only 1.2% of the measurements in the patients receiving placebo. Observation during treatment averaged 21 months; total intention-to-treat follow-up averaged 25 months. For the combined outcome events of transient ischemic attack, stroke, acute myocardial infarction, and vascular death, aspirin reduced risk by 11% (95% confidence limits: -38% to 48%, p greater than 0.1). Thus, there was no significant effect of very-low-dose aspirin in our trial.