Effect of dipyridamole therapy on myocardial ischemia in patients with stable angina pectoris receiving concurrent anti-ischemic therapy.

ABSTRACT

The effects of oral dipyridamole on exercise performance and anginal symptoms were evaluated in 15 men with stable angina pectoris. In a double-blind, randomized, crossover design, patients received 75 mg of dipyridamole or placebo every 8 hours for 2 weeks in addition to their previously prescribed cardiac medications. Graded exercise tolerance testing was performed twice before randomization, at the end of each treatment period, and after single-blind placebo washout. When compared with baseline tests, the time to onset of 0.1 mV ST-segment depression was similar between dipyridamole and placebo treatments (316 +/- 89 vs 345 +/- 102 seconds, respectively, p = not significant). No significant differences existed between treatments in the peak systolic blood pressure-heart rate product or in the duration of exercise. Angina pectoris occurred during all 3 baseline exercise tests in 7 of the 15 subjects; the time to onset of angina was unchanged by either treatment. Analysis of symptom diaries conducted in 13 patients revealed no significant alteration in reported anginal symptoms during dipyridamole treatment compared with placebo treatment (0.6 +/- 0.9 vs 0.3 +/- 0.4 episodes per week). Ambulatory electrocardiographic monitoring in 12 patients revealed few episodes of ischemia during daily activities with no alteration in frequency of episodes during treatment periods. Plasma concentrations of dipyridamole did not correspond with the outcomes of exercise testing. It is concluded that chronic oral dipyridamole therapy given in its usual clinical dose does not adversely affect exercise performance, daily anginal episodes or ambulatory ischemia in patients receiving concurrent anti-ischemic medication.