Design of the Heart failure Endpoint evaluation of AII-Antagonist Losartan (HEAAL) study in patients intolerant to ACE-inhibitor

Background: In patients with heart failure and reduced left ventricular ejection fraction, angiotensin receptor blockers have been found to reduce mortality and morbidity and to prevent or reverse left ventricular remodelling, compared to optimized background treatment. In light of these data, The Heart failure Endpoint evaluation of Angiotensin II Antagonist Losartan (HEAAL) study was developed to determine whether losartan 150 mg is superior to losartan 50 mg (antihypertensive dose) in reducing morbidity and mortality among patients with symptomatic heart failure who are intolerant of angiotensin-converting enzyme (ACE)-inhibitors. Aims/methods: To compare the effect of high and moderate doses of losartan on the primary endpoint of all-cause mortality and hospitalisation due to heart failure in patients (n = 3834) with symptomatic heart failure and an ejection fraction ≤ 40% who are intolerant of ACE-inhibitor treatment. Results: This paper presents the rationale, trial design, and baseline characteristics of the study population. The study, which completed recruitment on 31 March 2005, is event-driven and is estimated to accrue the target of 1710 adjudicated primary events during the latter half of 2008. Conclusions: The results of HEAAL should facilitate selection of an optimal dosing regimen for losartan in patients with symptomatic heart failure who are intolerant of ACE-inhibitors.