Angiotensin-converting enzyme inhibitors: ischemia is not the correct measure of benefit.

The recently published American College of Cardiology/ American Heart Association 2002 Guideline Update for Management of Patients with Chronic Stable Angina contains a comprehensive review of medications used for this purpose (2). Three classes of agents reviewed (beta-blockers, calcium antagonists, and nitrates) are effective for angina on the basis of altering the supply-demand imbalance created by flow-limiting coronary stenoses. These agents can reduce heart rate, blood pressure, and coronary vascular resistance, and redistribute coronary blood flow from subepicardial to subendocardial regions. The net effect is reduction in myocardial ischemia that leads to angina. The guideline update very importantly also reviews three other classes of agents used in chronic stable angina that affect fundamental activities of the vascular endothelium, either by altering endothelial cell function in certain favorable ways, or by reducing “inflammation” (a series of cytokine and leukocyte responses), or by preventing thrombosis. These other three therapeutic classes are antiplatelet agents, lipid-lowering agents (especially statins), and angiotensin-converting enzyme (ACE) inhibitors. The importance of these other classes in addition to the traditional triad of beta-blockers, calcium antagonists, and nitrates cannot be overstated.