Dual blockade versus single blockade of the renin–angiotensin system in the light of ONTARGET

Angiotensin II plays an important role in the cardiovascular continuum starting with risk factors and progressing to atherosclerosis, target organ damage, and ultimately to heart failure, stroke, or death. Inhibiting the renin-angiotensin-aldosterone system (RAAS) represents a cornerstone for the treatment of hypertension and heart failure. In patients with heart failure, the single RAAS blockade with angiotensin-converting enzyme (ACE) inhibitors have been shown to reduce morbidity and mortality, increase life expectancy, and preserve the renal function. AT1 receptor blockers (ARBs) are equally effective in reducing mortality and morbidity in patients with impaired left ventricular function. The combination of ACE inhibitors with ARBs leads to an additive blood pressure lowering effect, better reduction in proteinuria, and to additive benefits in heart failure and left ventricular hypertrophy. But combination therapy is also associated with more side effects. Further investigations evaluating the effect of dual RAAS blockade on fatal and nonfatal cardiovascular events are needed.