Beta-blockers raise the risk of a heart attack after surgery

A new study has found that for some patients undergoing surgery, beta-blockers before and around the time of the operation increases their risk of heart attack and death.

The research by scientists at the the Veterans Affairs Boston Health Care System, Boston University and Harvard Medical School has found that patients undergoing non-cardiac surgery appear to have higher rates of heart attack and death within 30 days of their surgery if they were taking beta-blockers.

For patients with a risk of death, stroke or heart attack, even non-cardiac surgery carries risks and the researchers say preventing such cardiac complications around the time of surgery events is the subject of intense research.

The study was prompted by reports of an increase in heart rate before such events and clinical reports of fewer complications in patients taking beta-blockers for hypertension and the researchers began investigating whether these medications should be given to patients undergoing surgery.

Dr. Haytham M. A. Kaafarani and colleagues examined 1,238 patients who underwent non-cardiac surgery - including plastic, vascular, abdominal or hernia repair surgery at a medical center in 2000.

Prior to their surgery the patients were classified as high, intermediate, low or negligible cardiac risk, and each procedure was also classified in the same way.

A total of 238 patients received beta-blockers perioperatively and were matched by age, sex, cardiac risk, procedure risk, smoking status and kidney health to 408 patients who also underwent surgery at the same center but did not receive beta-blockers.

The researchers say patients at all levels of cardiac risk who received beta-blockers had lower preoperative and intraoperative heart rates but over the 30 days following surgery, the beta-blocker group had higher rates of heart attack and death than those in the control group - and none of the deaths occurred among patients classified as high cardiac risk.

However, those in the beta-blocker group who died had significantly higher heart rates before surgery than those who didn't.

The research team say subtle as it may be, the finding suggests that a low target preoperative rather than intraoperative heart rate is essential for the protective effect of beta-blockers.

They say the relationship between preoperative (rather than intraoperative or postoperative) heart rate and perioperative mortality highlights the importance of not only initiating but also balancing the effect of beta-blockers to an acceptable target heart rate before surgery.

They suggest their study adds to the controversy regarding the optimal use of perioperative beta-blockers in patient populations at various levels of cardiac risk and say more research is called for in the standardizing of beta-blockade regimens and in the monitoring of heart rate in people with various levels of cardiac risk.

The research is published in the October issue of Archives of Surgery, one of the JAMA/Archives journals.