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 β blockers in high-risk patients undergoing noncardiac surgery. However, recent studies show that, in some instances, perioperative β blockade can cause harm. Furthermore, chronic β blockade, titrated to effect before surgery, may be superior to acute perioperative β blockade. The primary objective of this study was to compare major acute cardiac outcomes in patients who underwent surgery with chronic β blocker therapy with those in patients with acute β-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 β blocker, were calculated to match (1:1) the patients with acute and chronic β-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 β blocker before surgery; in 436 patients, the β 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 β-blocked patients (relative risk, 2.67; 95% CI, 1.27-5.60; P = 0.011). CONCLUSIONS Acute β 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 β blockade. These results should be validated in a larger prospective trial.