Treatment for heart attacks doesn't help all patients and harms women

Madrid.- The international clinical trial 'Reboot' has shown that beta-blockers, the drugs that have been prescribed for forty years after a myocardial infarction, not only do not provide any benefit to patients with uncomplicated heart attacks but, in addition, increase the risk of death or reinfarction in women.

'Reboot', coordinated by the Spanish National Center for Cardiovascular Research (CNIC), in collaboration with the Mario Negri Institute of Milan (Italy), was launched five years ago to determine if lifelong prescribed beta-blockers were necessary for heart attacks in which the heart's contraction had not decreased (uncomplicated heart attacks). Although the treatment manages to reduce heart rate, blood pressure, and contractility to improve blood flow to the arteries, it presents side effects such as fatigue, asthenia, or sexual dysfunction. The authors of the essay, in which more than 8,500 patients from 109 hospitals in Spain and Italy participated, have published the results in the journals 'The New England Journal of Medicine' and 'The Lancet', and are presenting them today at the Congress of the European Society of Cardiology being held in Madrid. Divided into two random groups, after hospital discharge, the trial participants received (or did not receive) beta-blockers. After a mean follow-up of four years, the researchers found no significant differences in mortality rates, reinfarction, or admission for heart failure between those who had taken the drugs and those who had not. "Reboot is going to change the treatment in these cases worldwide, since until now more than 80% of patients with this type of uncomplicated heart attack are discharged with beta-blocker treatment," says Borja Ibáñez, principal investigator of the study, scientific director of the CNIC and head of the group at the CIBER of cardiovascular diseases (CIBERCV). Furthermore, in a meta-analysis with other smaller trials, they confirmed that beta-blockers only significantly reduce the risk of death, recurrent heart attack, or heart failure in patients who, after a heart attack, have moderately reduced cardiac contractile function.

Every year, more than 2 million people suffer a heart attack in Europe. Until now, more than 80% of patients were discharged with treatment with beta-blockers, a practice that this trial questions.

"These findings will be the basis for the future treatment of myocardial infarction and will bring about a radical change in clinical practice guidelines," highlights Ibáñez, lead author of the meta-analysis.

Differences Between Sexes

Reboot has also revealed notable differences between sexes: while men experienced no benefit or risk when treated with beta-blockers, women who took these drugs had a significant increase in the risk of death, reinfarction, or hospitalization for heart failure compared to women who did not take them. Furthermore, women treated with beta-blockers had an absolute mortality risk 2.7% higher than those who were not treated with beta-blockers during the 3.7 years of follow-up of the study. Another important finding from the Reboot trial is that women who presented with heart attacks had a worse cardiovascular profile. They were older, had more comorbidities (including a higher prevalence of hypertension, diabetes, and dyslipidemia), and more frequently suffered heart attacks without obstruction of the coronary arteries (6% versus 2% in men). It should be noted that, in general, women had a significantly worse prognosis than men (mortality throughout the study was 4.3% in women versus 3.6% in men).

You may be interested in: Drug for cholesterol shows efficacy against dementia, according to Italian study

For Xavier Rosselló, CNIC scientist, cardiologist at the Son Espases University Hospital in Mallorca (Spain) and one of the people in charge of the trial, these findings show that "in many cases, prescribing beta-blockers to women after a heart attack without complications can be more harmful than beneficial. Doctors should carefully weigh the risks and benefits, and consider dose adjustments or alternative therapies when treating female patients," he adds.

Valentín Fuster, general director of the CNIC, president of the Mount Sinai Fuster Heart Hospital, underlines that "although we knew that the presentation of cardiovascular diseases is different in women and men, this study significantly contributes to this knowledge by demonstrating that the response to medications is not necessarily the same in women and men. This study should promote the much-needed sex-specific approach to cardiovascular diseases."