medwireNews: Early use of β blockers is still important in myocardial infarction patients without heart failure in the reperfusion era, a study suggests.
The French registry study found a significantly reduced risk of 30-day and 1-year mortality among myocardial infarction patients without heart failure who were given early β-blocker treatment.
“Most of the evidence on β blockers in patients with acute myocardial infarction dates back to the pre-reperfusion era”, say Etienne Puymirat (Hôpital Européen Georges Pompidou, Paris, France) and study co-authors.
And a lack of evidence in patients given reperfusion has led to downgrading of the recommendation for early β-blocker use in European (but not US) guidelines.
Nevertheless, 76.5% of the 2679 patients in this study, who underwent treatment for myocardial infarction during 1 month in 2005, received β blockers within 48 hours of admission. The majority of patients given β blockers had received reperfusion therapy, with 32% undergoing fibrinolysis and 39% percutaneous coronary intervention.
The 30-day mortality rate was 2.3% among patients given early β blockers, compared with 8.6% among those not. The risk of death was around 50% reduced among patients on β blockers after accounting for multiple confounders, after excluding patients who died within 48 hours of admission and among patients matched for their propensity to receive β blockers.
Furthermore, being given a β blocker at discharge conferred a long-term survival advantage. Of the 2217 patients who survived to hospital discharge, 80.4% were given β blockers and had a 1-year mortality rate of 3.4%, compared with 7.8% among those not given the medication. Again, the survival advantage persisted after adjustment for confounders and in a propensity-matched analysis.
These results “seem to be consistent with previous findings suggesting the beneficial effect of early β blocker treatment on survival in the first months after the acute episode, even in contemporary populations with high rates of primary percutaneous coronary intervention”, write the researchers in The BMJ.
However, the study suggests that long-term persistence with β blockers is not particularly beneficial in patients without heart failure, with 5-year mortality rates unaffected by whether or not patients were still taking β blockers a year after discharge.
By contrast, the 5-year mortality risk was more than halved in patients still taking statins a year after discharge, in line with the results of randomised trials, which, the team stresses, “unlike β blocker trials, were conducted in the contemporary era of reperfusion therapy and invasive strategies for patients with acute coronary syndromes.”
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