The New England Journal of Medicine has published the results of a study that aimed to assess the efficacy of irbesartan in reducing outcomes in patients with heart failure with preserved left ventricular ejection fraction.
The study recruited 4,128 participants aged 60 years and above with diagnosis of heart failure (NYHA II, III or IV) and with an ejection fraction of at least 45%. Participants were randomly assigned to treatment with irbesartan 300mg daily or placebo. The primary outcome for the study was a composite of death from any cause or hospital admission for a cardiovascular cause (heart failure, myocardial infarction, unstable angina, arrhythmia, or stroke).
Over the study period of just over 4 years the primary outcome occurred in 742 patients in the irbesartan group and 763 in the placebo group. This difference was not statistically significant. Similarly, there was no difference between the overall death rates and rates of hospital admission when analysed separately.
It is notable that over the period of the study the usage of angiotensin converting enzyme inhibitors (ACEI), beta-blockers and spironolactone increased in both groups. However, mean blood pressure was reduced by an additional 3.6/1.9mmHg in the active arm of the study.
These study results are consistent with the existing evidence and may reflect a poor scientific understanding of this condition. The authors of this study conclude that, "Irbesartan did not improve the outcomes of patients with heart failure and a preserved left ventricular ejection fraction".
Action: Clinicians should continue to implement existing recommendations for heart failure. ACEI should be used in preference to angiotensin receptor blockers with the latter being reserved for patients who are intolerant to ACEIs.