Angiotensin receptor blockers: powerful evidence with cardiovascular outcomes?

Angiotensin receptor blockers (ARBs) were developed to better antagonize the effects of chronic overactivation of angiotensin II. In clinical studies, ARBs have consistently been shown to be more tolerable than angiotensin-converting enzyme inhibitors (ACEis). Although many studies evaluating the benefits of ARBs in clinical practice are underway, relatively little information exists as to their benefits concerning cardiovascular events. In heart failure patients with ACEi intolerance, ARBs may improve survival. In patients who can tolerate an ACEi, ARBs reduce hospitalization. Due to a possible detrimental interaction when an ARB is added to the treatment of patients already taking an ACEi and a beta-blocker, the use of ARBs in such heart failure patients is not generally indicated. ARBs also preserve renal function and may reduce cardiovascular events in patients with pre-existing renal dysfunction and type 2 diabetes. However, there is no convincing evidence that ARBs improve the survival of these patients. Thus, ARBs should be used on their own merits and should not be used as substitutes for ACEis in this patient population. Studies to establish the status of ARBs in the treatment and prevention of cardiovascular diseases are ongoing, but until they are completed, care should be taken in extrapolating the effects of ARBs to those of ACEis.