Is addition of angiotensin receptor blockade superior to increasing ACE inhibitor dose in patients with heart failure?
We conducted a prospective, randomised, open-label, blinded end point (PROBE) study examining the relative efficacy of irbesartan 300 mg/day versus maximising dose of ACE inhibitor, additional to background conventional heart failure therapy. Patients with CHF, NYHA Class II-III and a left ventricular ejection fraction <40% were randomised to one of two treatment arms. All patients were receiving ≤ half target dose of ACE inhibitor as background therapy. 44 patients received an increase in their background ACE inhibitor while 45 patients were given irbesartan (target dose 300 mg/day) in addition to their background ACE inhibitor. The primary end-point was change in brain natriuretic peptide (BNP) from baseline to 6 months. Change in hs-CRP level, 6 min walk distance, and Minnesota living with heart failure quality of life questionnaire (MLWHF) from baseline to 6 months were also evaluated. Patients were well matched at baseline for all end-point parameters as well as for age, gender and baseline systolic ventricular function. There was general improvement in clinical status for all patients but no significant difference between increased ACE inhibitor vs added ARB for change in BNP, hs-CRP, NYHA, 6 min walk or MLWHF (all P>0.05). This PROBE study has demonstrated similar clinical responses with increased dose of ACE inhibitor compared to addition of ARB in patients with systolic CHF. These findings suggest that either approach to increasing renin-angiotensin blockade in patients taking low doses of background ACE inhibitor results in similar clinical outcomes.