Beta-blockers offer no survival advantages to patients, post-heart attack, but they do improve survival among some heart failure patients.
The former finding was made by two groups in a recent issue of The American Journal of Medicine (AJM). Beta-blockers, which manage arrhythmias, have been treating heart attack survivors for 25 years. But much of the data was accumulated before the onset of statins, reperfusion, and antiplatelets.
Beta blockers offer little help post-heart attack
Recently, there have been questions about these drugs. Two new studies looked at the traditional handling of these patients after hospital discharge, in addition to the impact of the discharge heart rate and conventional treatment with beta-blockers.
A team led by NYU Medical Center’s Sripal Bangalore examined 60 randomized trials with 102,003 patients evaluating beta-blockers in myocardial infarction. Each trial enrolled at least 100 patients. Fourteen trials (20,418 patients) provided data on a follow-up of more than one year. Trials were grouped into those taking place in the reperfusion era (more than 50% undergoing reperfusion or receiving aspirin/statin) and those occurring before.
Researchers compared reperfusion, aspirin and statin therapy versus beta-blocker use and outcomes in heart attack patients. They also examined the role of early intravenous beta-blockers; and the duration of beta-blocker use. They found beta-blockers have no mortality benefit in treatment of heart attacks today.
The study found 30-day use can reduce recurrent heart attack and angina, but that this had to be weighed against an increase in heart failure, cardiogenic shock and drug discontinuation.
In the second AJM study, the team of François Schiele, Chief of Cardiology at the Jean-Minjoz University Hospital, analyzed discharge heart rate in acute coronary syndrome patients and assessed the impact of discharge heart rate on five-year mortality in hospital survivors.
In the last 20 years there has been increasing use of heart rate as a marker for risk levels of cardiovascular diseases, and as a prognostic factor for global and cardiovascular mortality. But there are few data on the long-term impact.
The discharge heart rate was analyzed in more than 3,000 patients discharged over a one-month period in 223 institutions in the French Registry of Acute ST Elevation, or non-ST-Elevation Myocardial Infarction (FAST-MI). Patients were followed for five years. The objective of FAST-MI is to evaluate practices for managing heart attacks in “real life” conditions, and to measure their relationship with acute and long-term outcomes of heart attack patients in coronary care units. A heightened ST segment seen on an electrocardiogram indicates that a lot of heart muscle damage is occurring.
Heart rate was looked at in four groups: over 60, 61 to 67, 68 to 75, and over 75 beats (high) per minute. After a year, the team identified many factors related to a high heart rate, including ST-elevation myocardial infarction, diabetes, renal dysfunction, chronic obstructive pulmonary disease, left ventricular dysfunction, and prescription of beta blockers at discharge.
The discharge heart rate was “significantly” associated with one-year mortality, and patients discharged with a high heart rate were at higher risk of death during the first year, irrespective of beta-blocker use.
Beta blockers aid survival in heart failure
Meanwhile, however, a third recent study, led by Lars Lund of the Karolinska Institutet, found bet- blockers improve survival in certain types of heart failure. The study asked whether beta-blockers can be linked to reduced mortality in heart failure patients with preserved ejection fraction (left ventricle pumps with each contraction). In a recent issue of The Journal of the American Medical Association (JAMA), his team reported that as many as 50% of heart failure patients have normal or near-normal ejection fraction, or heart failure with preserved ejection fraction (HFPEF). The risk of death in HFPEF may be as high as in heart failure with reduced ejection fraction (HFREF), but there is no proven therapy. Beta-blockers improve outcomes in HFREF and may be beneficial in HFPEF, but data are not good, and beta-blockers are not generally prescribed for HFPEF
The researchers used data from the Swedish Heart Failure Registry, which included 41,976 patients, 19,083 patients with HFPEF. Of these, 8,244 were matched 2:1 based on age and beta-blocker use, with 5,496 treated and 2,748 untreated patients having HFPEF. Another analysis involved 22,893 patients with HFREF, of whom 6,081 were matched, yielding 4,054 treated with beta-blockers and 2,027 untreated patients.
In the matched HFPEF cohort, five-year survival was 45% vs 42% for treated vs untreated patients, with 2,279 (41%) vs 1,244 (45%) total deaths, and a 7% reduction in the risk of death.
Beta-blockers were not associated with reduced combined mortality or heart failure hospitalizations: 3,368 (61%) vs 1,753 (64%) total for first events. But in the matched HFREF cohort, beta-blockers were associated with reduced mortality, and reduced combined mortality or heart failure hospitalization.
