The effect of captopril on the coronary circulation and myocardial metabolism of patients with coronary artery disease.

The acute effects of captopril in three groups of patients with coronary artery disease were studied: 25 patients with congestive heart failure; 8 patients with hypertension; and 14 normotensive patients with angina, and systolic arterial pressure greater than 120 mmHg, but no evidence of heart failure. Systemic haemodynamics were assessed by balloon-tipped thermodilution catheter and coronary haemodynamics were assessed by thermodilution catheter in the coronary sinus. Despite significantly different baseline haemodynamic values, captopril decrease systolic arterial pressure without increasing heart rate in all three groups, thereby decreasing double-product, a major determinant of myocardial work. Coronary blood flow and myocardial oxygen consumption decreased similarly in all groups and decreased in parallel to double-product, while coronary vascular resistance and transmyocardial oxygen difference did not change except for a slight decrease in transmyocardial oxygen difference in those patients with congestive heart failure. Transmyocardial lactate extraction increased insignificantly. These findings suggest that captopril may improve metabolic balance in various types of patients with coronary artery disease and that it does this by decreasing myocardial oxygen demand.