June 2023
Long-term beta-blocker therapy may not be needed for all after MI: more evidence
By Rebecca Jenkins
Long-term treatment with beta blockers post-myocardial infarction (MI) is not associated with improved cardiovascular outcomes in patients without heart failure or left ventricular systolic dysfunction (LVSD), an observational study finds.
Researchers conducted a nationwide cohort study of 43,618 patients with their first MI presentation who were recorded in the Swedish register for coronary heart disease between 2005 and 2016.
All included patients were free of heart failure or LVSD up until the index date of one-year post-MI presentation, the researchers reported in Heart. The median age of participants was 64 years and 25.5% of the cohort were female.
At the index date, 34,253 (78.5%) patients were on beta-blocker therapy and 9365 (21.5%) were not.
In an intention-to-treat analysis, the unadjusted rate of the primary composite outcome of all-cause mortality, MI, unscheduled revascularisation and hospitalisation for heart failure was lower among patients who received beta blockers compared with those who did not (3.8 vs 4.9 events/100 person years). However, following inverse propensity score weighting and multivariable adjustment, researchers found the risk did not differ between the groups over a median follow up of 4.5 years.
Similar findings were observed when censoring for beta-blocker discontinuation or treatment switch during follow up, the researchers said.
‘The findings of our study align with the results of a recent meta-analysis of contemporary trials evaluating the role of [beta blockers] after MI in patients with no heart failure or LVSD,’ they wrote.
‘In patients with MI without heart failure or LVSD, long-term treatment with [beta blockers] should be reassessed.’
Commenting on the findings, Professor Derek Chew, Director of MonashHeart and the Victorian Heart Hospital, Monash Health, in Melbourne, said the research supported prior evidence around the role of long-term beta-blocker therapy in this patient group.
‘The methodology of this latest study is robust and consistent with literature from over a decade ago, and practice is steadily embracing this,’ he told Medicine Today.
Professor Chew, who was lead author of the 2016 National Heart Foundation of Australia and Cardiac Society of Australia and New Zealand’s clinical guidelines for the management of acute coronary syndromes, noted recommendations for beta blockers had been downgraded in that guidance.
The latest study further supported the guidelines’ recommendation that low-risk asymptomatic patients or those with preserved LV ejection fraction benefit the least from beta-blocker therapy, which could be ceased at 12 months post-MI, Professor Chew said.
‘However, among patients with concomitant issues such as ongoing stable angina or hypertension, in the context of normal LV function, a beta blocker may still be a rational choice,’ he added.