A common treatment given after heart attacks may not be worthwhile for a large segment of the population. New trial data finds that most people who suffer a heart attack do not benefit from taking beta-blockers afterward.
A large international team of researchers conducted the trial, which compared the outcomes of nearly 10,000 heart attack patients who were either given beta-blocker therapy or not.
On average, people with preserved heart function given beta-blockers were no less likely to die or to experience a second heart attack than those not given beta-blockers, the researchers found. Secondary data also showed that women might actually face a higher risk of complications from taking these medications.
“This trial will reshape all international clinical guidelines,” said senior study author Valentin Fuster, president of Mount Sinai Fuster Heart Hospital, in a statement from Mount Sinai.
Why doctors use beta-blockers
For more than 40 years, beta-blockers have been a key aspect of treating and managing cardiovascular disease. These drugs block the effects of adrenaline on the body’s beta-receptors, which then reduces heart rate and lowers blood pressure (among other bodily changes). They’re often used to reduce stress on a badly damaged heart following a heart attack (myocardial infarction), in theory lowering the risk of a second heart attack or other cardiovascular issues.
But heart medicine has evolved greatly since the arrival of the first beta-blockers in the 1960s. New treatments and improved knowledge have made it easier for doctors to prevent these infarctions from causing as much damage to the heart as before. And that’s led some researchers to wonder whether beta-blockers should still be considered a front-line treatment following heart attacks, including the team behind this large new trial.
A therapy in need of a reboot
The team’s trial, named REBOOT, involved roughly 8,500 people. The patients had all experienced relatively mild heart attacks and appeared to have a left ventricular ejection fraction (LVEF) above 40%. LVEF measures how well our left ventricle (the main pumping chamber) pumps out blood. A healthy LVEF is typically considered above 51%, while slightly reduced function is between 40% and 50%.
Half of the patients were randomized to receive beta-blockers after being discharged from the hospital, while the other half received none. Both groups were then tracked for several years (median length 3.7 years).
By the study’s end, there wasn’t any significant difference in outcomes between the two groups. Deaths (from any cause), secondary heart attacks, and hospitalizations from heart failure occurred just as often in the beta-blocker group as they did in the control group.
Since these kinds of heart attacks represent the majority of cases (roughly 80%) today, the team’s findings—published over the weekend in the New England Journal of Medicine—indicate that beta-blockers shouldn’t be a standard treatment for most heart attack patients, the researchers say.
Harmful for some, useful for others
While beta-blocker therapy may be worthless for most male heart attack patients, it could be actively dangerous to women in particular.
In a secondary analysis of the REBOOT results, published in the European Heart Journal, women on beta-blockers had higher rates of heart attacks, hospitalization, and death than women not on the drug. On closer inspection, this added risk was only seen in women who maintained normal heart function (LVEF above 50%). Though it’s not entirely clear why only women might experience this risk, studies have found that heart attacks can present differently in women compared to men and cause differing symptoms.
The findings should better optimize the long-term care of heart attack patients, who are often already prescribed multiple medications to keep their cardiovascular health in check. “These results will help streamline treatment, reduce side effects, and improve quality of life for thousands of patients every year,” said lead author Borja Ibáñez, scientific director of Spain’s National Center for Cardiovascular Research (CNIC), in a statement.
That said, the REBOOT trial won’t bury beta-blockers for good. The drugs may still help prevent complications in people with severe heart attacks and are widely used for other conditions, including congestive heart failure, migraines, and even performance anxiety.
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