Role of angiotensin-converting enzyme inhibition in angina pectoris

There are various reasons to assume a beneficial effect of angiotensin-converting enzyme (ACE) inhibitors in patients with angina pectoris. Reduction of preload and afterload and a sympatholytic action may diminish myocardial oxygen demand. Local vasodilatory effects on the coronary vasculature may cause a relative increase in myocardial oxygen supply, although this can be nullified by the reduction in coronary perfusion pressure. Despite these potentially beneficial effects, placebo-controlled studies on exercise testing have shown variable results and do not justify the widespread use of these agents in chronic effort-induced angina pectoris. Nevertheless, certain subgroups of anginal patients may be identified in whom further studies are needed, especially patients who have unstable angina pectoris or are in the acute phase of myocardial infarction, patients with left ventricular dysfunction without overt heart failure, and patients with hypertension and left ventricular hypertrophy. Apart from this, ACE inhibitors may potentiate the effects of nitrates and reverse tolerance, especially inhibitors that contain a sulfhydryl group. In additional studies, a low starting dose and a long duration of treatment appear to be essential to optimize tissue penetration in the heart and to minimize negative effects due to the reduction in perfusion pressure.