Angiotensin II and trials of cardiovascular outcomes

Proven cardiovascular benefit from angiotensin-converting enzyme (ACE) inhibition is a cornerstone of evidence-based medicine. The first study to show dramatic benefits from ACE inhibition was the Cooperative North Scandinavian Enalapril Survival Study (CONSENSUS-I), in which a 31% decrease in the rate of death was observed in patients with severe heart failure at the end of 1 year of enalapril treatment (p = 0.001). This result led to large long-term studies—including Survival and Ventricular Enlargement (SAVE), Acute Infarction Ramipril Efficacy (AIRE), Trandolapril Cardiac Evaluation (TRACE), and Study of Left Ventricular Dysfunction (SOLVD)—which verified that ACE inhibition decreases heart failure, myocardial infarction (MI), and mortality, and that striking benefit could be observed within 30 days. Short-term studies of patients in the acute phase of a heart attack verified that ACE inhibition provided rapid benefits. A meta-analysis of short-term (up to 8 weeks) studies of ACE inhibition (including CONSENSUS-II, Gruppo Italiano per lo Studio della Sopravvivenza nell’Infarto Miocardico [GISSI]-3, International Study of Infarct Survival [ISIS]-4, and the Chinese Captopril Study [CCS]-1) demonstrated that post-MI risk was reduced by 10% within the first day of treatment. The immediacy of the benefit suggested that ACE inhibition not only improved cardiovascular function in failing hearts but also affected important mechanisms in patients without overt heart failure. Effects on more general mechanisms of heart disease suggested that patients with problems other than hypertension or heart failure might benefit from ACE inhibitors. The Heart Outcomes Prevention Evaluation (HOPE) study investigated the hypothesis that ACE inhibition would confer benefits to patients who were at high risk for cardiovascular events, but who were without left ventricular dysfunction or heart failure. Long-term reductions in MI, stroke, cardiac arrest, and heart failure, as well as improvements in mortality, were observed in this population after treatment with ACE inhibitors. Substudies of the HOPE study revealed that ACE inhibition reduced progression of atherosclerosis and improved myocardial remodeling. Taken together, these studies provide evidence that supports treatment of a broad population of patients at risk for cardiovascular events with ACE inhibitors. The next step is to combine ACE inhibition with other treatments to maximize patient benefit. The Ongoing Telmisartan Alone and in combination with Ramipril Global Endpoint Trial (ONTARGET) will compare the efficacy of an ACE inhibitor (ramipril) with an angiotensin receptor blocker (telmisartan), and determine whether these treatments in combination will further reduce morbidity and mortality from cardiovascular disease.