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Aspirin Before Surgery May Reduce Mortality Risk

Taking aspirin before coronary bypass surgery may be less risky than previously believed. A recent retrospective study has found no association between pre-surgical aspirin use and the risk of significant post-operative bleeding, doctors’ primary concern.

The study by R. Scott Wright, MD, a cardiologist, and colleagues at the Mayo Clinic College of Medicine, was published online in Circulation and reported on MedPage Today 30 August 2005.

Wright and colleagues also determined that aspirin use before surgery was linked to a significantly lower risk of death due to all causes and death due to cardiac incidents during the post-operative hospital stay.

Study Protocol

The study group included 1,636 consecutive patients undergoing coronary artery bypass surgery for the first time. Most patients were male, and the average age was 69 years.

Researchers compared aspirin use within the five days before coronary bypass surgery with the incidence of adverse in-hospital postoperative events.

A total of 1,316 patients had received aspirin during the five days before surgery, while 320 patients had not. Because patients in this retrospective study could not be randomized into aspirin-taking and non-aspirin-taking groups, researchers adjusted for numerous potentially difficult variables, including hypertension, history of congestive heart failure, high cholesterol, smoking status and diabetes.

Patients who took aspirin preoperatively were more likely to have previously had a myocardial infarction (MI) – and to have had an MI in the 21 days preceding coronary bypass surgery. Secondly, patients who took aspirin preoperatively were more likely to have taken beta-blockers preoperatively, too. The group who did not take preoperative aspirin had a larger proportion of patients on dialysis.

Results of Data Analysis

Of the patients who took aspirin preoperatively, 22 (1.7%) died in the hospital after surgery, compared with 14 (4.4%) of patients who did not take aspirin. This difference amounted to a 61% lower incidence of all-cause mortality in the aspirin-taking group, compared with the non-aspirin-taking group.

Similarly, death associated with cardiovascular events in the aspirin-taking group was 0.5%, compared with 2.2% in the non-aspirin-taking group.

Among both groups, the rate of re-operation necessitated by serious bleeding was slightly higher than 3%. The rate of postoperative adverse cerebrovascular events in the aspirin-taking group was 2.7%, compared with 3.8% in the non-aspirin-taking group.

"The study further confirms aspirin’s benefits for patients with known cardiovascular disease," Dr. Wright said, according to MedPage Today. "It also shows there is no increased risk of bleeding, which eliminates the main reason why physicians and surgeons would ask patients to discontinue aspirin therapy.

“Patients with heart disease who are not taking aspirin should ask themselves – and their doctors – ‘Why not?’”

Posted: September 2005