Beta blockers prescribed following myocardial infarction may not prevent mortality, according to a new study which puts current NICE guidelines into question.
The observational study, published this week in Journal of the American College of Cardiology, found that in patients who had suffered myocardial infarction without heart failure, there was no significant difference in death rates between those who were and were not taking beta blockers.
Researchers, led by a team from the University of Leeds, looked at data collected between 2007 and 2013 from nearly 180,000 English and Welsh survivors of acute myocardial infarction without heart failure included on the Myocardial Ischaemia National Audit Project.
Just under 95% of patients received beta blockers during the study period. Adjusted figures showed no significant reduction in mortality when patients took beta blockers compared to when they did not.
The researchers suggested that given the potential harmful side effects and the difficulty in patient adherence to increasing numbers of drugs, beta blockers could potentially be removed as a secondary prevention drug for patients with myocardial infarction being discharged from hospital.
This is in contrast to current NICE guidelines, which recommend that patients who have had an acute myocardial infarction without heart failure should be offered a beta blocker for at least 12 months following the attack.
The paper said: ‘Many patients with acute myocardial infarction are prescribed beta blockers ad infinitum regardless of whether they have left ventricular systolic dysfunction, heart failure, or neither.
’It is probable that this practice is, in part, supported by clinical uncertainty because evidence suggesting clinical benefit associated with the use of beta blockers in the context of acute myocardial infarction is varied, historical, extrapolated from nongeneralizable data, and unclear for acute myocardial infarction patients without heart failure.’
Dr Marlous Hall, lead investigator and senior epidemiologist at the Leeds Institute of Cardiovascular and Metabolic Medicine, said: ’What we need now is a randomised patient trial. We were investigating one outcome – did beta blockers increase a patient’s chances of survival?
’A trial would allow researchers to substantiate these findings and also look at other outcomes, such as whether beta blockers prevent future heart attacks. This work would have implications for personalising medications after a heart attack.’
Professor Ahmet Fuat, GPSI in cardiology and president of the Primary Care Cardiovascular Society, said: ’There is little evidence for using beta blockers long term after acute myocardial infarction unless the patient has heart failure or continues to have anginal symptoms. Many do get side effects, but far less so with newer cardioselective beta blockers.
’We need a randomised controlled trial that addresses the mortality and morbidity benefits of beta blocker use post-acute myocardial infarction but in the meantime, clinicians should tailor beta blocker use to individual patients.’
J. Am. Coll. Cardiol. 2017; available online 29 May
