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The treatment of heart failure. A methodological review of the literature
Insights
Long-term randomized trials show angiotensin-converting enzyme inhibitors significantly improve heart failure outcomes. Other drugs like digoxin and nitrates offer modest benefits to specific patient groups.
Area of Science:
- Cardiology
- Pharmacology
- Clinical Trials
Background:
- Heart failure treatment relies on various medications, but evidence quality varies significantly.
- Short-term and uncontrolled studies often yield discrepant results compared to long-term randomized controlled trials.
Purpose of the Study:
- To review the literature on major heart failure drugs, focusing exclusively on long-term randomized controlled trials.
- To evaluate the efficacy of digoxin, oral nitrates, hydralazine, quinazolone derivatives, and angiotensin-converting enzyme inhibitors in heart failure management.
Main Methods:
- Systematic review of long-term randomized controlled trials (RCTs) for heart failure medications.
- Analysis of trial outcomes for digoxin, oral nitrates, hydralazine, prazosin, trimazosin, captopril, and enalapril.
Main Results:
- Digoxin showed benefit in only 1 of 3 RCTs, suggesting utility for a minority.
- Oral nitrates reduced left ventricular filling pressure, with trends favoring exercise capacity.
- Angiotensin-converting enzyme inhibitors (captopril, enalapril) demonstrated dramatic and consistent improvements in exercise capacity and functional status.
Conclusions:
- Angiotensin-converting enzyme inhibitors are recommended for symptomatic heart failure patients on optimal diuretic therapy.
- Digoxin may be considered for patients whose functional capacity remains reduced despite optimal therapy.
- Prazosin and trimazosin may offer modest benefits to some heart failure patients.
Abstract:
In this article literature concerning the major drugs used in the treatment of heart failure is reviewed. Because of major discrepancies in results from short term and uncontrolled studies versus long term randomised control trials, only the latter group of studies are addressed in detail. Of 3 randomised control trials of digoxin, 1 has been positive, and 2 negative. Digoxin is probably of benefit to a minority of heart failure patients. Four randomised control trials of oral nitrates have shown a reduction in left ventricular filling pressure, and trends favouring active treatment for the indices of exercise capacity and functional status. Of 2 randomised control trials of hydralazine one is totally negative, the other difficult to interpret because of major loss of patients to followup. Of 5 trials of quinazolone derivatives (prazosin and trimazosin), 2 have been positive, 2 showed non-statistically significant trends favouring active treatment, and 1 was completely negative. These results are consistent with a modest benefit of prazosin and trimazosin in some heart failure patients. Five trials of angiotensin-converting enzyme inhibitors (captopril and enalapril) have shown dramatic and consistent benefit in exercise capacity and functional status. These results support a clinical policy of initial treatment with diuretics and addition of either captopril or enalapril for patients who remain symptomatic on optimal diuretic therapy. A trial of digoxin is warranted in patients whose functional capacity remains reduced on this regimen.