Effect of amlodipine on exercise‐induced platelet activation in patients affected by chronic stable angina

Background: Literature concerning exercise‐induced platelet activation in chronic stable angina is somewhat confusing. The reason lies in the type of exercise as well as in methodological problems. A powerful, recently introduced procedure to detect platelet activation is flow cytometry. Platelet response to activating factors is mediated by calcium uptake; however, calcium antagonist effect on platelet activity is still unclear. Hypothesis: The study was undertaken to investigate exercise‐induced platelet activation before and after treatment with amlodipine in chronic stable angina. Methods: Twenty patients with chronic stable angina were entered into the study. Each subject underwent a symptom‐limited cycloergometer stress test following a washout period of 2 weeks. Blood samples were collected before and immediately after exercise. All subjects were then randomized into two groups of 10 patients each, with Group 1 and Group 2 taking amlodipine 10 mg/day, and placebo for 4 weeks, respectively. They subsequently underwent a second exercise stress test, and blood samples were obtained before and immediately after exercise. Flow‐cytometric evaluation of platelet activity was performed in order to recognize GMP‐140 expression on platelet membrane. Results: Strenuous exercise induced a significant increase in platelet activation in all subjects prior to therapy. No significant differences were observed in platelet activity at rest between Groups 1 and 2, whereas a significant decrease in exercise‐induced platelet activation was demonstrated in Group 1 compared with Group 2. Conclusion: Our data provide evidence of the favorable effect of amlodipine on exercise‐induced platelet activation in patients affected by chronic stable angina.