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.


OBJECTIVE
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.


CONCLUSIONS
Our data provide evidence of the favorable effect of amlodipine on exercise-induced platelet activation in patients affected by chronic stable angina.
Sanguigni
V
V
Department of Internal Medicine, University of Rome Tor Vergata, Italy.
Gallù
M
M
Sciarra
L
L
Del Principe
D
D
Menichelli
A
A
Palumbo
G
G
Cannata
D
D
Strano
A
A
D000368:Aged; D017311:Amlodipine / Q000494:pharmacology / Q000627:therapeutic use*; D000787:Angina Pectoris / Q000097:blood* / Q000188:drug therapy* / Q000503:physiopathology; D002118:Calcium / Q000037:antagonists & inhibitors; D002121:Calcium Channel Blockers / Q000494:pharmacology / Q000627:therapeutic use*; D004311:Double-Blind Method; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D008297:Male; D008875:Middle Aged; D015539:Platelet Activation / Q000187:drug effects; D018709:Statistics, Nonparametric
D002121:Calcium Channel Blockers; D017311:Amlodipine; D002118:Calcium