Perioperative Metoprolol and Risk of Stroke after Noncardiac Surgery

BACKGROUND: Numerous risk factors have been identified for perioperative stroke, but there are conflicting data regarding the role of β adrenergic receptor blockade in general and metoprolol in particular. METHODS: The authors retrospectively screened 57,218 consecutive patients for radiologic evidence of stroke within 30 days after noncardiac procedures at a tertiary care university hospital. Incidence of perioperative stroke within 30 days of surgery and associated risk factors were assessed. Patients taking either metoprolol or atenolol were matched based on a number of risk factors for stroke. Parsimonious logistic regression was used to generate a preoperative risk model for perioperative stroke in the unmatched cohort. RESULTS: The incidence of perioperative stroke was 55 of 57,218 (0.09%). Preoperative metoprolol was associated with an approximately 4.2-fold increase in perioperative stroke (P < 0.001; 95% CI, 2.2-8.1). Analysis of matched cohorts revealed a significantly higher incidence of stroke in patients taking preoperative metoprolol compared with atenolol (P = 0.016). However, preoperative metoprolol was not an independent predictor of stroke in the entire cohort, which included patients who were not taking β blockers. The use of intraoperative metoprolol was associated with a 3.3-fold increase in perioperative stroke (P = 0.003; 95% CI, 1.4-7.8); no association was found for intraoperative esmolol or labetalol. CONCLUSIONS: Routine use of preoperative metoprolol, but not atenolol, is associated with stroke after noncardiac surgery, even after adjusting for comorbidities. Intraoperative metoprolol but not esmolol or labetalol, is associated with increased risk of perioperative stroke. Drugs other than metoprolol should be considered during the perioperative period if β blockade is required.