Association of β-blocker therapy with risks of adverse cardiovascular events and deaths in patients with ischemic heart disease undergoing noncardiac surgery: a Danish nationwide cohort study.

IMPORTANCE: Clinical guidelines have been criticized for encouraging the use of β-blockers in noncardiac surgery despite weak evidence. Relevant clinical trials have been small and have not convincingly demonstrated an effect of β-blockers on hard end points (ie, perioperative myocardial infarction, ischemic stroke, cardiovascular death, and all-cause death).

OBJECTIVE: To assess the association of β-blocker treatment with major cardiovascular adverse events (MACE) and all-cause mortality in patients with ischemic heart disease undergoing noncardiac surgery. DESIGN, SETTING, PARTICIPANTS, AND EXPOSURE: Individuals with ischemic heart disease with or without heart failure (HF) and with and without a history of myocardial infarction undergoing noncardiac surgery between October 24, 2004, and December 31, 2009, were identified from nationwide Danish registries. Adjusted Cox regression models were used to calculate the 30-day risks of MACE (ischemic stroke, myocardial infarction, or cardiovascular death) and all-cause mortality associated with β-blocker therapy.

MAIN OUTCOMES AND MEASURES: Thirty-day risk of MACE and all-cause mortality.

RESULTS: Of 28,263 patients with ischemic heart disease undergoing surgery, 7990 (28.3%) had HF and 20,273 (71.7%) did not. β-Blockers were used in 4262 (53.3%) with and 7419 (36.6%) without HF. Overall, use of β-blockers was associated with a hazard ratio (HR) of 0.90 (95% CI, 0.79-1.02) for MACE and 0.95 (0.85-1.06) for all-cause mortality. Among patients with HF, use of β-blockers was associated with a significantly lower risk of MACE (HR, 0.75; 95% CI, 0.70-0.87) and all-cause mortality (0.80; 0.70-0.92), whereas among patients without HF, there was no significant association of β-blocker use with MACE (1.11; 0.92-1.33) or mortality (1.15; 0.98-1.35) (P < .001 for interactions). Among patients without HF, β-blockers were also associated with a lowered risk among those with a recent myocardial infarction (<2 years), with HRs of 0.54 (95% CI, 0.37-0.78) for MACE and 0.80 (0.53-1.21) for all-cause mortality (P < .02 for interactions between β-blockers and time period after myocardial infarction), but with no significant association in the remaining patients. Results were similar in propensity score-matched analyses.

CONCLUSIONS AND RELEVANCE: Among patients with ischemic heart disease undergoing noncardiac surgery, use of β-blockers was associated with lower risk of 30-day MACE and mortality only among those with HF or recent myocardial infarction.