The Heart Outcomes Prevention Evaluation study: angiotensin-converting enzyme inhibitors: are their benefits a class effect or do individual agents differ?

The Heart Outcomes Prevention Evaluation study was a landmark study employing the angiotensin-converting enzyme inhibitor ramipril in a patient population pre-destined for vascular events. This study found that a 10 mg dose of ramipril in comparison with placebo reduced the incidence of death, myocardial infarction, stroke, and death from cardiovascular causes by 22%. This improvement in outcome was viewed as a direct consequence of ramipril, although the fact that blood pressure was reduced with ramipril has cast some considerable doubt on this supposition. Whether the observed findings in this study are a 'class effect' for all angiotensin-converting enzyme inhibitors is unclear. To its credit, ramipril is the first angiotensin-converting enzyme inhibitor shown to prevent ischemic events in high-risk patients without discernible left ventricular dysfunction. Other similar trials are underway, which are studying similar populations to those included in this landmark study and should resolve the question of whether the cardioprotective effects of angiotensin-converting enzyme inhibitors are a 'class effect'.