ACE: Aspirin and Carotid Endarterectomy - a Randomized Trial

Welcome to the ACE web site!

This web site describes a randomized clinical trial, known as ACE. It includes information on the design, conduct and results of the study. We hope that it will be useful to those interested in this particular trial, and to students and young investigators in the process of launching a research career of their own.

What's The Study About?
Patients whose carotid arteries have become narrowed by atherosclerosis frequently have warning symptoms which indicate that they are at risk of suffering a stroke. If the narrowing is severe enough (over 70%) the risk of stroke can be greatly reduced by a surgical procedure known as carotid endarterectomy. Patients with less severe narrowing (50-69%) also benefit but only if they are at high risk of stroke due to other medical risk factors. But, unfortunately the operation is not without risk. 4% to 6% of patients suffer a stroke or a heart attack, and about 1% die, as a direct result of the operation.

In the past 20 years a large body of clinical research has demonstrated that aspirin is effective in reducing the risk of stroke in these patients, however physicians disagree on the amount of aspirin that is required. The purpose of the ACE study was to determine whether the risk of stroke, heart attack and death within 30 days (and 3 months) following carotid endarterectomy surgery depends on the dose of Aspirin that patients take before and after the operation.

To answer this question we designed a study in which 2800 patients would be randomly assigned to receive 80, 325, 650 or 1300 mg of aspirin per day, starting before surgery, with 1/4 of the patients going to each of the 4 treatment groups. The grant application for this study was written and submitted to the National Institute of Neurological Disorders and Stroke (N.I.N.D.S) in 1993. The study was launched in 1994, completed in 1998 and published in the Lancet in 1999.

We found that patients who had been randomized to take 81 or 325 mg of aspirin per day had fewer strokes, heart attacks and deaths compared with patients who took 650 or 1300 mg of aspirin per day.

Most of the documents on this web site are in PDF format. You will need Adobe Acrobat Reader to read them. If you don't have it, the latest version can be downloaded free of charge via this link .

Questions and comments can be directed:
Wayne Taylor - principal investigator
Professor
Department of Clinical Epidemiology and Biostatistics
McMaster University, Hamilton, ON, Canada
Email: dwt@datafax.com

ACE: Aspirin and Carotid Endarterectomy - a Randomized Trial

Table of Contents