Chronic β Blockade Is Associated with a Better Outcome after Elective Noncardiac Surgery than Acute β Blockade A Single-center Propensity-matched Cohort Study

Background: Current guidelines on perioperative care recommend the prophylactic use of beta blockers in high-risk patients undergoing noncardiac surgery. However, recent studies show that, in some instances, perioperative beta blockade can cause harm. Furthermore, chronic beta blockade, titrated to effect before surgery, may be superior to acute perioperative beta blockade. The primary objective of this study was to compare major acute cardiac outcomes in patients who underwent surgery with chronic beta blocker therapy with those in patients with acute beta-blocker therapy. Methods: Data were collected for 10,691 consecutive patients undergoing elective noncardiac surgery between April 1, 2008, and April 30, 2010. Propensity scores, estimating the probability of receiving a preoperative beta blocker, were calculated to match (1:1) the patients with acute and chronic beta-blocker therapy. The primary outcome was a composite of myocardial infarction, nonfatal cardiac arrest, and perioperative mortality. The rate of cardiac events was compared in the matched cohorts. Results: A total of 962 patients were chronically treated with a beta blocker before surgery; in 436 patients, the beta blocker was administrated acutely. Propensity score matching created 301 patient pairs who were well-balanced for major comorbidities, concomitant drug use, and type of surgery. The primary outcome was observed in 9 (3.0%) chronic versus 24 (8.0%) acute beta-blocked patients (relative risk, 2.67; 95% CI, 1.27-5.60; P = 0.011). Conclusions: Acute beta blockade, initiated within the first 2 days after surgery, was associated with worse cardiac outcome compared with a matched cohort of patients who underwent surgery on chronic beta blockade. These results should be validated in a larger prospective trial.