Study questions use of Beta-blockers post-MI

Whilst used extensively in the last 40 years after acute myocardial infarction (MI) as part of therapy and in secondary prevention, the evidence for doing so routinely rests largely on results of trials conducted over 25 years ago. A new meta-analysis including over 100 000 study participants suggests that clinical guidelines recommending the use of beta-blockers in post-MI patients need to be reconsidered.

In their meta-analysis which included 60 clinical trials with 102,003 patients, published in the American Journal of Medicine1the researchers observed a significant interaction between clinical outcomes and reperfusion era. For example, in the prereperfusion era, which mainly included trials with intravenous beta-blockers, there was a significant 14% relative reduction in all-cause mortality, as well as a 13% relative reduction in cardiovascular mortality, a 22% reduction in MI, and a 12% reduction in angina. In this era, there was no increased risk of heart failure or cardiogenic shock.

The conclusions of the researchers, led by Dr Sripal Bangalore, are that: “In contemporary practice of treatment of myocardial infarction, â-blockers have no mortality benefit but reduce recurrent myocardial infarction and angina (short-term) at the expense of increase in heart failure, cardiogenic shock and drug discontinuation. The guidelines should reconsider the strength of recommendations for â-blockers post myocardial infarction.”

1 Bangalore S, Makani H, Radford M, et al. Clinical outcomes with beta-blockers for myocardial infarction. Am J Med2014; DOI: 10.1016/j.amjmed.2014.05.032