Beta-blocker therapy and angina burden after myocardial infarction: A prespecified substudy of the BETAMI-DANBLOCK trial.

AIMS: The effect of beta-blockers initiated after myocardial infarction (MI) on subsequent angina burden remains uncertain. METHODS AND RESULTS: This pre-specified BETAMI-DANBLOCK substudy included patients with MI and left ventricular ejection fraction (LVEF)≥40% randomized to beta-blockers or no beta-blockers. Endpoints comprised angina-related hospital contacts/diagnostic ischemia tests, coronary revascularization, anti-anginal medications (≥2 prescriptions for calcium-channel blockers/nitrates), and patient-reported angina symptoms [Canadian Cardiovascular Society (CCS) class 0-4]. Subdistribution hazard ratios (SHR) were estimated by Fine-Gray models. Anti-anginal prescriptions were compared using 95% confidence intervals (CI) for differences in proportions.A total of 5574 patients were randomized to beta-blockers (n=2783, median dose 50 mg metoprolol) or no beta-blockers (n=2791). During median 3.5 years follow-up, an angina-related hospital contact/diagnostic ischemia test occurred in 724 patients (26.0%) in the beta-blocker group vs. 834 (29.9%) in the no beta-blocker group (SHR 0.85; 95% CI, 0.77-0.94). Coronary revascularization occurred in 108 (3.9%) vs. 110 patients (3.9%)(SHR 0.99; 95% CI 0.76-1.29). Fewer patients in the beta-blocker group were treated with calcium-channel blockers [630(22.7%) vs. 738(26.6%); -3.9 percentage points (95% CI, -6.2 to -1.6)], whereas nitrate use [342(12.3%) vs. 356(12.8%); -0.5 (95% CI, -2.2 to 1.2)] and CCS-scores were similar between groups (difference in change at 12-months, -0.04; 95% CI, -0.14-0.05). CONCLUSIONS: In patients with MI and LVEF≥40%, a moderate dose of beta-blockers was associated with a lower incidence of first angina-related hospital contact/diagnostic ischemia testing, and lower use of calcium-channel blockers. The absence of differences in coronary revascularization, nitrate use and patient-reported angina symptoms suggests that the overall benefit on angina is limited.