Meta-Analysis of Perioperative Beta-Blockers Doesn’t Support Routine Use
Clinical question: Are perioperative beta-blockers effective in preventing cardiac events in noncardiac surgery?
Background: The American College of Cardiology (ACC) and American Heart Association (AHA) guidelines for noncardiac surgery recommend beta-blockers for high-risk patients undergoing intermediate or high-risk surgery. The results of previous randomized controlled trials have been inconsistent.
Study design: Meta-analysis.
Setting: Literature search of PubMed, Embase, and the Cochrane Library.
Synopsis: Thirty-three randomized, controlled trials—which included 12,306 patients—were selected for statistical analysis. In these trials, beta-blockers were initiated in the perioperative period with 30-day followup for outcomes of interest. Overall, perioperative beta-blocker use was associated with a 35% risk reduction in nonfatal MI, a 116% increased risk of nonfatal stroke, and no significant difference in all-cause mortality. Trials with higher levels of bias showed greater statistical benefit of beta-blockers. Of note, the POISE trial carried the largest amount of weight, accounting for nearly two-thirds of the total number of patients included in treatment arms.
The application of this data is challenging, as studies differ in several important variables, such as timing of beta-blocker initiation, dosing regimen, and duration of treatment. The POISE trial, in particular, employed a very large dose of metoprolol, compared with doses of beta-blockers used in other studies. There is less data regarding the perioperative efficacy of beta-blockers when therapy is started well before surgery.
Bottom line: Current evidence does not support the routine use of beta-blockers started immediately prior to noncardiac surgery to prevent perioperative cardiac events.
Citation: Bangalore S, Wetterslev J, Pranesh S, et al. Perioperative beta-blockers in patients having non-cardiac surgery: a meta-analysis. Lancet. 2008;372:1962-1976.
Perioperative Ischemic Stroke an Important Cause of Morbidity and Mortality in Noncardiac Surgery
Clinical question: What are the incidence, risk factors, and outcomes of acute ischemic stroke in nonvascular surgery?
Background: Ischemic stroke is a well-understood complication of cardiovascular surgery. However, little data exist in medical literature regarding the frequency, associations, and outcomes of perioperative ischemic stroke in noncardiac surgery.
Study design: Observational chart review using administrative data.
Setting: The Nationwide Inpatient Sample, a public-use database, in which approximately 1,000 hospitals submit data from nonfederal acute-care hospitals.
Synopsis: Three common surgeries were sampled from an administrative database to characterize the epidemiology of perioperative ischemic stroke in noncardiac surgery. This outcome occurred in 0.7% of hemicolectomy patients; 0.2% of total hip replacement patients; and 0.6% of lobectomy/segmental lung resection patients. Studying the rate of perioperative ischemic stroke in coronary artery bypass graft (CABG) patients validated the authors’ method of data extraction. This rate was consistent with prior studies of this outcome in cardiovascular surgery patients.
Multivariate analysis showed that renal disease (odds ratio 3.0), atrial fibrillation (OR 2.0), prior stroke (OR 1.6), and valvular disease (OR 1.5) are statistically associated with an increased risk of perioperative ischemic stroke. The primary outcome was associated with a marked increase in the odds of in-hospital mortality or need for chronic care upon hospital discharge.
This study is limited by its use of administrative coding data, as well as potential bias introduced by the use of only three major types of surgery.
Bottom line: Ischemic stroke is a serious complication of intermediate and major noncardiovascular surgery. It is associated with poor patient outcomes; more evidence is needed to confirm associations with this outcome and to discover strategies to reduce risk.
Citation: Bateman B, Schum-acher H, Wang S, et al. Perioperative acute ischemic stroke in non-cardiac and nonvascular surgery. Anesthesiology. 2009;110:231-238.