Inhibition of RAAS--when is it too much?

Deactivation of the renin-angiotensin-aldosterone system (RAAS) is clearly beneficial in patients with recent myocardial infarction and chronic heart failure. Most of the experience with deactivation of the RAAS has been collected in placebo-controlled randomized trials of angiotensin- converting enzyme inhibition (ACEI). The hypothesis that angiotensin receptor blockade may be a better approach to deactivate the RAAS has not survived the test of time. Despite the extensive experience with ACEI and aldosterone receptor blockade in patients with recent myocardial infarction and chronic heart failure, several issues remain unanswered. These are addressed in this review.