Aspirin Reduces Complications From Cardiac Surgery

Jim Kling

October 25, 2010

October 25, 2010 (San Diego, California) — The use of aspirin immediately preceding cardiac surgery significantly reduces the incidence of cardiocerebral ischemic events, according to research presented here at the American Society of Anesthesiologists 2010 Annual Meeting.

Patients undergoing cardiac surgery often suffer from postoperative cardiocerebral ischemic events, such as stroke and cardiac arrest. "The major complications associated with cardiac surgery are still common, and costly. More important, there is no proof of a therapy to prevent those major cardiocerebral complications," said Jian-Zhong Sun, MD, PhD, associate professor of anesthesiology at Jefferson Medical College in Philadelphia, Pennsylvania, who presented the research.

Previous research has indicated that aspirin can improve the overall outcome in patients undergoing coronary artery bypass grafting (CABG). To determine the effectiveness of aspirin on postoperative cardiocerebral ischemic events, the researchers conducted a retrospective study of 1879 patients at their institution who underwent cardiac surgery (mostly CABG and valve surgery) between August 2003 and December 2009.

The researchers excluded patients who had taken preoperative anticoagulants, unknown aspirin use, and those who underwent emergency surgery. They recorded permanent or transient stroke, coma, perioperative myocardial infarction, heart block, and cardiac arrest. The researchers also looked at 30-day mortality.

The 1148 patients who met the inclusion criteria were divided into 2 groups: those taking aspirin (n = 860) and those not taking aspirin (n = 288) in the 5 days before surgery. There was no significant difference between the groups in baseline parameters, such as body mass index, preoperative use of digitalis or diuretics, and history of chronic lung disease, cerebrovascular disease, heart failure, cardiogenic shock, or smoking.

Those taking aspirin were more likely to have a history of hypertension (84.5% vs 69.3%; P < .001), diabetes (35.2% vs 23.6%; P < .001), peripheral arterial disease (11.1% vs 4.2%; P < .001), previous myocardial infarction (25.9% vs 14.6%; P < .001), angina (29.1% vs 17.4%; P < .001), and a family history of coronary artery disease (58.9% vs 43.2%; P < .001). They also tended to be older (65.4 ± 12.0 years vs 59.1 ± 15.3 years; P < .001) and were more likely to be male (70.3% vs 58.9%; P < .001).

Patients who had taken aspirin were more likely to have used preoperative beta blockers and renin-angiotensin system inhibitors. They were also more likely to have left main and multiple coronary artery disease, but to have spent less time in cross-clamp and bypass perfusion. Multivariate logistic regression showed that preoperative aspirin use reduced postoperative cardiocerebral ischemic events (8.6% vs 12.9%; P = .037). The adjusted odds ratio (OR) was 0.638 (95 % confidence interval [CI], 0.418 - 0.976). There was no significant difference in 30-day mortality between the 2 groups (4.2% vs 5.8%; OR, 0.708; CI, 0.0386 -1.301; P = .264).

Currently, patients are typically advised to stop taking aspirin a week before surgery because of concern about bleeding during an operation, Dr. Sun said. The researchers found no increased incidence of readmission in the aspirin group; however, "we have no direct evidence" of benefit, he acknowledged.

The next step will be a "randomized multicenter trial on a larger scale to change the recommendation for preoperative medications. But we saw quite a drop [in complications]. If we can confirm [the finding], it will change common practice," said Dr. Sun.

"It's informative, but I wish [the study] was 10 times the size. They only were able to include a quarter of the patients that they planned to," Daniel Sessler, MD, professor of outcomes research at the Cleveland Clinic, in Ohio, who moderated the session, told Medscape Medical News.

Others also sounded a note of caution. "There are lots of reasons to think aspirin might have benefits to patients, but there's no question that there are increased risks of bleeding. Until we demonstrate that there's a clear benefit in this setting, I think one should be cautious about how strongly one is advising use of the drug. We're going to need large clinical trials to get an answer," P.J. Devereaux, MD, PhD, associate of cardiology at McMaster University in Hamilton, Ontario, who attended the presentation, told Medscape Medical News.

Dr. Devereaux noted that several large clinical trials are now underway: "I'm hopeful that in the next couple of years we'll have a clearer picture as to what the benefits of aspirin are so that people can make much more informed choices."

The study did not receive commercial support. Dr. Sun, Dr. Sessler, and Dr. Devereaux have disclosed no relevant financial relationships.

American Society of Anesthesiologists (ASA) 2010 Annual Meeting: Abstract 1190. Presented October 19, 2010.

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