Updated ACC/AHA guidelines urge consideration of patient risk-benefit ratio for perioperative beta-blocker administration

The American College of Cardiology and American Heart Association have released a focused update concerning the prophylactic use of beta-blockers during noncardiac surgery.

The focused update included a review of clinical evidence of the effects of perioperative beta-blocker therapy in several patient populations. The ACC/AHA Guidelines on Perioperative Cardiovascular Evaluation and Care for Noncardiac Surgery were last updated in 2007.

“In this update, a Class I indication for perioperative beta-blocker use exists for continuation of a beta-blocker in patients already taking the drug,” the authors wrote. “In addition, several Class IIa recommendations exist for patients with inducible ischemia, coronary artery disease or multiple clinical risk factors who are undergoing vascular surgery for patients with coronary artery disease or multiple clinical risk factors who are undergoing immediate-risk surgery.”

POISE study

Specifically, the focused update incorporated new data from the POISE trial, a large, randomized study of high-dose, extended-release metropolol in 8,351 patients undergoing noncardiac surgery. Patients in the POISE trial were randomly assigned to receive either extended-release metropolol succinate (Toprol XL, Astra Zeneca) or placebo two to four hours prior to noncardiac surgery, with continued administration for 30 days following the procedure. The results, though mixed, prompted the authors to update the guidelines for perioperative beta-blocker therapy.

“This study confirmed a reduction in primary cardiac events such as CV death, MI and cardiac arrest with perioperative beta-blocker therapy,” the authors wrote in the updated guidelines. “However, that benefit was offset by an increased risk for stroke and total mortality, which suggests that routine administration of high-dose beta blockers in the absence of dose titration is not useful, may be harmful and cannot be advocated, which results in a new Class III recommendation for this practice.”

Despite the addition of data from the POISE trial to the guidelines, the authors cautioned that there remains a relative lack of information for guidance in the use of beta-blocker therapy in the setting of shifts from traditional open procedures toward less invasive endovascular and percutaneous techniques that may not require general anesthesia.

Approaches to titration

The authors also focused on the titration of beta-blocker therapy in patients undergoing low-risk, intermediate-risk and high-risk surgical procedures. A titrated approach to beta-blocker administration in high-risk patients rather than a fixed higher dose was generally recommended, particularly in patients naïve to beta-blocker therapy. The authors also noted that the results from the POISE trial, the largest trial of its kind to date and the only one powered to confirm such a result, suggested that sufficient benefit to warrant use of fixed-dose perioperative beta-blocker administration was not demonstrated.

“Overall, available evidence suggests that beta-blockers, if used, should be appropriately titrated throughout the preoperative, intraoperative and postoperative period to achieve effective heart rate control while avoiding frank hypotension and bradycardia,” the authors wrote.

They also recommended against the abrupt withdrawal of beta-blocker therapy.

“Although the data are limited, perioperative beta-blocker withdrawal should be avoided unless necessary,” they wrote. “As noted in the recommendations, continuation of beta-blocker therapy in the perioperative period is a Class I indication, and accumulating evidence suggests that titration to maintain effective heart rate control while avoiding frank hypertension and bradycardia should be the goal.”

Fleisher L. J Am Coll Cardiol. 2009;doi:10.1016/j.jacc.2009.07.010.