Patients who took beta-blockers during non-cardiac surgery had increased risk of acute coronary syndrome, decompensated heart failure, and arrhythmia, according to the results of a study.
Although beta-blockers are currently recommended by the American College of Cardiology/American Heart Association 2011 guidelines to manage the risk of adverse cardiovascular events before and after surgery, a new study finds that the drugs may actually increase the risk of cardiac events in patients undergoing non-cardiac surgery.
The retrospective study, presented on October 30, 2013, at CHEST 2013, the annual meeting of the American College of Chest Physicians, evaluated the risks and benefits of beta-blocker use before, during, and after non-cardiac surgery. Among patients who had undergone non-cardiac surgery at a university-based center, 755 patients were randomly selected for inclusion in the study and were classified according to gender, ethnicity, risk of surgery, and whether beta-blockers were used. Researchers from the State University of New York Upstate Medical University Hospital evaluated the risk of all-cause mortality, acute coronary syndrome, arrhythmias, bradycardia, decompensated heart failure, and death caused by cardiac events. To predict these outcomes, beta-blocker administration, Revised Cardiac Index Score, and the risk of surgery were studied for each patient.
The results indicated that patients who used beta-blockers had an increased risk of having an acute coronary event. Beta-blockers also increased the risk for decompensated heart failure (odds ratio of 4.50) and, surprisingly, arrhythmias (odds ratio of 2.28). The overall event rate was small, however, and confidence intervals were wide. The authors of the study note that statistical correctional formulas were used in order to stabilize these results.
The results suggest that perioperative beta-blocker use may increase the risk of adverse cardiac events, decompensated heart failure, and arrhythmias in patients undergoing non-cardiac surgery. The researchers suggest that the drugs may only be beneficial in some surgery patients. “Benefit may be limited only to the high risk category, including current chronic users and those who would benefit from beta-blocker use by virtue of cardiac pathology, irrespective of surgery,” they write.
However, given the small event rate, a larger study is needed to confirm the results before any definite conclusions and new recommendations on beta-blocker use can be made.