Role of Presurgery Beta-Blockers Remains Unclear

A published commentary by heart specialists makes a plea for clarity on the best approach for prescribing β-blockers before surgery.

Clinicians at the University of Michigan Health System (U-M; Ann Arbor, USA) claim that due to important design, treatment, and analytical variations, previous clinical trials regarding the presurgical administration of β-blockers are hard to interpret. For instance, they state that the 2001 Dutch Echocardiographic Cardiac Risk Evaluation Applying Stress Echocardiography (DECREASE) study included high-risk patients with known coronary blockages who faced high-risk surgery, and the β-blockers were given based on individual heart rate and blood pressure. In contrast, the 2008 Perioperative ischemic evaluation (POISE) study included a mixed group of patients undergoing major noncardiac surgery who were taking a long-acting drug. Given these important differences, the authors claim that both past and current studies have not offered clear answers about who should get β-blockers, what the starting dose should be, and how doses should be adjusted for patients. The commentary was published in the February 10, 2010, issue of the Journal of the American Medical Association (JAMA).

"The time has come for clarity across perioperative β-blocker studies. A one-size-fits-all approach for prescribing β -blockers can harm patients at low-risk for having a heart attack,” concluded study authors Vineet Chopra, M.D., a clinical assistant professor of internal medicine, and Kim Eagle, M.D., director of the U-M Cardiovascular Center. "Future clinical studies using clear models of dose, duration and implementation could provide answers for doctors about the role of presurgery β-blockers.”

Perioperative cardiac events are common and thought to result from coronary plaque rupture, myocardial oxygen supply-demand mismatch, or a combination of these processes. In theory, β-blockers are ideal for preventing these events, because they decrease myocardial oxygen requirements (by lowering heart rate and reducing blood pressure) and are thought to stabilize atherosclerotic plaque. However, perioperative β-blockade has become controversial because of conflicting results of recent studies. Based on the latest evidence, the American College of Cardiology Foundation (ACCF) and American Heart Association (AHA) joint guidelines restricted the once-broad indication for perioperative β-blockers to include only patients already receiving this therapy.

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