Maintenance Aspirin Not Linked to Bleeding, Major Cardiac Events: Meta-Analysis

August 13, 2012

By Gabriel Miller

NEW YORK (Reuters Health) Aug 09 - Maintenance doses of aspirin prescribed after acute coronary syndrome do not have a significant effect on bleeding or major adverse cardiac event rates, a meta-analysis suggests.

Dr. Jeffrey S. Berger at New York University and colleagues analyzed 136 studies involving 289,330 patients with acute coronary syndrome who were managed with stents or medical treatment.

In the stent group (81,807 patients), a low dose was defined as 75-159 mg and a high dose as 160-325 mg. Most patients in the stent group received clopidogrel and aspirin, with lesser numbers receiving ticlopidine, ticagrelor, prasugrel, and cangrelor.

In the medical treatment group (207,523 patients), a low dose was 75-149 mg, a high dose was 150-325 mg, and an additional "very high dose" was >325 mg. Patients in the medical management group predominantly received either thrombolytic or mixed medical therapies along with aspirin.

Major bleeding, myocardial infarction and all-cause death were analyzed at one, six, and 12 months. In general there were no significant differences in any of the clinical outcomes at any time point based on aspirin dose.

The lone exception was major bleeding at one month in the medical therapy group, where the rate was 4.0% in the high-dose group vs 1.7% in the low-dose group.

According to the study authors, only two randomized trials have looked directly at long-term maintenance doses of aspirin in these patients.

The lack of prospective data is a reason for caution when interpreting the study's results, Dr. Sanjit Jolly, an interventional cardiologist at McMaster University in Hamilton, Ontario, Canada, told Reuters Health by email. Dr. Jolly was involved with one of the prospective trials but not with the meta-analysis.

Historically, Dr. Jolly said, cardiologists in the U.S. have used higher doses while those in Europe have favored a lower dose approach.

"Due to large geographic differences in prescribing patterns, the confounding is a significant limitation of observational studies," Dr. Jolly said.

However, because low-dose aspirin appears to be as effective as higher dose aspirin and there does not seem to be a major difference in bleeding, Dr. Jolly believes "it is reasonable to use low-dose aspirin" in clinical practice.

Full results of the study were published online July 18 in the American Heart Journal. Dr. Berger, the lead author, did not respond to a request for comment on the study's findings.

The study was sponsored by AstraZeneca.


Am Heart J 2012.