POISE: The Muddle of Beta Blockers in Noncardiac Surgery

The publication of the Perioperative Ischemic Evaluation trial (the POISE study) this week in The Lancet has the cardiology world in a semi-tizzy, since it suggests that certain guidelines published by the American Heart Association (AHA) and the American College of Cardiology (ACC) are causing more harm than good.

At issue is the question of whether patients having noncardiac surgery who are at increased risk for coronary artery disease ought to be given beta blockers in the perioperative period (i.e. during the time immediately before, during, and after surgery). Previous studies have shown that perioperative beta blockers in such patients can reduce the risk of heart attacks during and after surgery. Subsequently, the AHA and ACC created guidelines recommending perioperative beta blockers in patients at increased risk who are having noncardiac surgery.

Unfortunately, the POISE study (which enrolled over 8000 patients from 23 countries who were over 45 years of age, had increased cardiac risk, and were having noncardiac surgery) showed that, while the risk of heart attack was indeed reduced in patients randomized to beta blockers, they also had a significantly increased risk of stroke and death. Overall, the use of beta blockers in these patients led to net harm.

The results of the POISE study - a carefully conducted, very large, randomized, controlled clinical trial whose results appear solid - calls into question the AHA/ACC guidelines, and the guidelines committees are already scrambling to make revisions. In the meantime, if you are about to have noncardiac surgery and you are at increased risk for heart disease, you ought to talk with your surgeon to make sure he/she is aware of this latest information. (Assess your risk for heart disease here.)

It should be noted, however, that the POISE study did not address patients who are already taking beta blockers for other reasons. All agree that these patients should remain on their beta blockers through surgery.