Evidence for the efficacy of ARBs across the cardiovascular continuum.

Introduction: Angiotensin II receptor blockers (ARBs) are antihypertensive agents with considerable evidence of efficacy and safety for the reduction of cardiovascular (CV) disease risk in numerous patient populations from one end of the CV continuum (i.e., primary prevention among patients with CV risk factors) to the other (i.e., secondary prevention in the post-MI setting). There are several agents within the ARB class, all of which have contributed to various degrees to this evidence base.

Scope: This review presents the design and main results of large, well designed studies examining the CV risk-reducing properties of ARBs. The authors searched major literature databases (Embase, Medline, PubMed) for randomized, controlled studies published between January, 1995 and October, 2009 that compared ARBs with placebo or active controls and reported major CV outcomes (e.g., myocardial infarction, stroke) and/or mortality as the primary study endpoint(s).

Limitations: Although many trials evaluating similar agents are presented, between-trial comparisons are inappropriate. The results of each study stand on their own merits and weaknesses, but do not provide any additional insight into the results of the other studies.

Results: Agents in the ARB class have demonstrated efficacy in reducing CV events and/or mortality in a number of different patient populations, from primary prevention studies in patients with pre-specified risk factors (e.g., hypertension and left-ventricular hypertrophy in the LIFE study) to secondary prevention (i.e., post-MI patients in the VALIANT study). Some studies have also demonstrated the statistical equivalence of ARBs to ACE inhibitors in certain populations (e.g., among post-MI patients in VALIANT and among a broad population of patients with vascular disease or diabetes in the ONTARGET). There are several major studies currently underway that will provide further information on the risk-reducing properties of ARBs in additional populations (e.g., patients with impaired glucose tolerance in the NAVIGATOR study).

Conclusions: ARBs have demonstrated efficacy in reducing CV morbidity and mortality in a broad spectrum of CV disease states across the CV continuum. Ongoing research continues to provide additional evidence, with ongoing trials investigating their role in additional patient populations.