title: Association of perioperative β-blockade with mortality and cardiovascular morbidity following major noncardiac surgery.
abstract: OBJECTIVE
  The effectiveness of perioperative β-blockade in patients undergoing noncardiac surgery remains controversial.
  
  
  OBJECTIVE
  To determine the associations of early perioperative exposure to β-blockers with 30-day postoperative outcome in patients undergoing noncardiac surgery.
  
  
  METHODS
  A retrospective cohort analysis evaluating exposure to β-blockers on the day of or following major noncardiac surgery among 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.
  
  
  METHODS
  All cause 30-day mortality and cardiac morbidity (cardiac arrest or Q-wave myocardial infarction).
  
  
  RESULTS
  Overall 55,138 patients (40.3%) were exposed to β-blockers. Exposure was higher in the 66.7% of 13,863 patients undergoing vascular surgery (95% CI, 65.9%-67.5%) than in the 37.4% of 122,882 patients undergoing nonvascular surgery (95% CI, 37.1%-37.6%; P < .001). Exposure increased as Revised Cardiac Risk Index factors increased, with 25.3% (95% CI, 24.9%-25.6%) of those with no risk vs 71.3% (95% CI, 69.5%-73.2%) of those with 4 risk factors or more exposed to β-blockers (P < .001). Death occurred among 1.1% (95% CI, 1.1%-1.2%) and cardiac morbidity occurred among 0.9% (95% CI, 0.8%-0.9%) of patients. In the propensity matched cohort, exposure was associated with lower mortality (relative risk [RR], 0.73; 95% CI, 0.65-0.83; P < .001; number need to treat [NNT], 241; 95% CI, 173-397). When stratified by cumulative numbers of Revised Cardiac Risk Index factors, β-blocker exposure was associated with significantly lower mortality among patients with 2 factors (RR, 0.63 [95% CI, 0.50-0.80]; P < .001; NNT, 105 [95% CI, 69-212]), 3 factors (RR, 0.54 [95% CI, 0.39-0.73]; P < .001; NNT, 41 [95% CI, 28-80]), or 4 factors or more (RR, 0.40 [95% CI, 0.25-0.73]; P < .001; NNT, 18 [95% CI, 12-34]). This association was limited to patients undergoing nonvascular surgery. β-Blocker exposure was also associated with a lower rate of nonfatal Q-wave infarction or cardiac arrest (RR, 0.67 [95% CI, 0.57-0.79]; P < .001; NNT, 339 [95% CI, 240-582]), again limited to patients undergoing nonvascular surgery.
  
  
  CONCLUSIONS
  Among propensity-matched patients undergoing noncardiac, nonvascular surgery, perioperative β-blocker exposure was associated with lower rates of 30-day all-cause mortality in patients with 2 or more Revised Cardiac Risk Index factors. Our findings support use of a cumulative number of Revised Cardiac Risk Index predictors in decision making regarding institution and continuation of perioperative β-blockade. A multicenter randomized trial involving patients at a low to intermediate risk by these factors would be of interest to validate these observational findings.
authors.affiliation: Department of Anesthesia and Perioperative Care, US Department of Veterans Affairs Medical Center and University of California, San Francisco, San Francisco, CA 94121, USA. londonm@anesthesia.ucsf.edu
authors.forename: Martin J
authors.initials: MJ
authors.lastname: London
authors.forename: Kwan
authors.initials: K
authors.lastname: Hur
authors.forename: Gregory G
authors.initials: GG
authors.lastname: Schwartz
authors.forename: William G
authors.initials: WG
authors.lastname: Henderson
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000368:Aged; D015331:Cohort Studies; D016208:Databases, Factual; D005260:Female; D006323:Heart Arrest / Q000401:mortality* / Q000517:prevention & control; D006801:Humans; D008297:Male; D008875:Middle Aged; D009017:Morbidity; D009203:Myocardial Infarction / Q000401:mortality* / Q000517:prevention & control; D059035:Perioperative Period; D012189:Retrospective Studies; D012306:Risk; D013514:Surgical Procedures, Operative; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology; D014493:United States Department of Veterans Affairs / Q000706:statistics & numerical data
chemical_list: D000319:Adrenergic beta-Antagonists