April 24, 2013
Study Examines Outcomes Of Use Of Beta-Blockers Around Time Of Surgery For Higher-Risk Patients
Patients at elevated cardiac risk who were treated with beta-blockers on the day of or following noncardiac, nonvascular surgery had significantly lower rates of 30-day mortality and cardiac illness, according to a study in the April 24 issue of JAMA.
"The effectiveness and safety of perioperative beta-blockade [the process of inhibiting beta-receptor activity] for patients undergoing noncardiac surgery remains controversial. Class I recommendations in the current American Heart Association/American College of Cardiology Foundation Guidelines on Perioperative Evaluation and Care for Noncardiac Surgery remain limited to continuation of preexisting beta-blockade," according to background information in the article. "Recent evidence suggests that use of perioperative beta-blockade may be declining. Contributing factors may include uncertainty about safety and recent data questioning the efficacy of long-term beta-blockade in stable outpatients. Thus, additional multicenter analyses of associations of perioperative beta-blockade with outcome are timely and potentially relevant to clinicians and regulatory agencies promoting perioperative quality and safety efforts."Martin J. London. M.D., of the U.S. Department of Veterans Affairs Medical Center and University of California, San Francisco, and colleagues conducted a study to examine the association of perioperative beta-blockade with all-cause 30-day mortality and cardiac morbidity (cardiac arrest or Q-wave [a reading on an electrocardiogram] myocardial infarction) in patients undergoing major noncardiac surgery. The analysis included a population-based sample of 136,745 patients who were 1:1 matched on propensity scores (37,805 matched pairs) treated at 104 VA medical centers from January 2005 through August 2010.
Overall, 45,347 patients (33.2 percent) had an active outpatient prescription for beta-blockers within 7 days of surgery and 55,138 patients (40.3 percent) were potentially exposed to beta-blockers on either postoperative day 0 or 1. Inpatient beta-blocker exposure was higher in the 66.7 percent of 13,863 patients who underwent vascular surgery than in the 37.4 percent of 122,882 patients who underwent nonvascular surgery. The rate of use increased with increasing Revised Cardiac Risk Index variables: 25.3 percent for no factors vs. 71.3 percent for 4 or more factors.
Overall, 1,568 patients (1.1 percent) sustained the primary 30-day mortality outcome and 1,196 patients (0.9 percent) the secondary cardiac morbidity outcome. The researchers found that in the matched cohort, patients in the exposed group had a 27 percent lower risk of mortality. Significant associations of beta-blocker exposure with lower mortality were noted in patients with 2 Revised Cardiac Risk Index factors (37 percent lower mortality risk), 3 factors (46 percent lower risk), or 4 factors or more (60 percent lower risk). This association was limited to patients undergoing nonvascular surgery.
Considering the secondary cardiac morbidity outcome, beta-blocker exposure was associated with a 33 percent lower risk of cardiac complications, also limited to patients undergoing nonvascular surgery.
"In conclusion, our results suggest that early perioperative beta-blocker exposure is associated with significantly lower rates of 30-day mortality and cardiac morbidity in patients at elevated baseline cardiac risk undergoing nonvascular surgery. Although assessment of cumulative number of Revised Cardiac Risk Index predictors might be helpful to clinicians in deciding whether to use perioperative beta-blockade, the current findings highlight a need for a randomized multi-center trial of perioperative beta-blockade in low- to intermediate-risk patients scheduled for noncardiac surgery," the authors write.
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