Initiating treatment with the selective beta-blocker, bisoprolol, is as effective and well tolerated as beginning treatment with an ACE inhibitor. However, starting treatment with bisoprolol may reduce the risk of death especially in the first year of treatment.
These findings from the Cardiac Insufficiency BIsoprolol Study III (CIBIS III) challenge the current assumption that treatment of heart failure should begin with an ACE inhibitor subsequently followed by a beta-blocker.
CIBIS III is the first large prospective study to compare the two drug initiation strategies. In newly diagnosed patients over age 65 years (mean age 72 years) treatment was either begun with bisoprolol (n=505 ) or enalapril (n=505). Subsequently, all patients received combination treatment of the two agents. Treatments were titrated to usually recommended doses.
By the end of the study there were no significant differences in either the efficacy or tolerability of the two treatment arms. As a result, one of the principal investigators, Professor Ronnie Willenheimer, Director of Research Unit in the Department of Cardiology at the University Hospital Malmo, Sweden said: "CIBIS III challenges the view that treatment of heart failure patients should be started with an ACE inhibitor rather than a beta-blocker. CIBIS III questions the logic behind such a recommendation."
Evaluating patients after the first year of treatment in a post-hoc analysis, CIBIS III suggests there was a benefit in starting patients on bisoprolol rather than enalapril. In the initial year of treatment, 42 patients in the bisoprolol-first group had died versus 60 deaths in the enalapril-first group; a difference of 31% (p=0.065).
Professor Willenheimer said: "Current treatment guidelines recommend that patients with heart failure should begin with an ACE inhibitor, to which a beta-blocker should be added. This strategy has never been tested before in a large, well conducted comparative prospective trial.