Effects of exercise on platelet reactivity after myocardial infarction: a randomized clinical trial

Exercise training (ET) can lower platelet reactivity in patients with cardiovascular risk factors. However, the effects of ET on platelet reactivity in higher-risk patients is unknown. The aim of this study was to evaluate the effects of ET on platelet reactivity in patients with recent myocardial infarction (MI). Ninety patients were randomly assigned 1 month post-MI to the intervention (patients submitted to a supervised ET program) or control group. All patients were on dual antiplatelet therapy (DAPT). Platelet reactivity by VerifyNow-P2Y12 (measured by P2Y12 reaction units - PRUs) test was determined at baseline and at the end of 14 ± 2 weeks of follow-up at rest (primary endpoint), and multiplate electrode aggregometry (MEA) adenosine diphosphate (ADP) and aspirin (ASPI) tests were performed immediately before and after the maximal cardiopulmonary exercise test (CPET) at the same time points (secondary endpoints). Sixty-five patients (mean age 58.9 ± 10 years; 73.8% men; 60% ST elevation MI) completed follow-up (control group, n = 31; intervention group, n = 34). At the end of the follow-up, the mean platelet reactivity was 172.8 ± 68.9 PRUs and 166.9 ± 65.1 PRUs for the control and intervention groups, respectively (p = .72). Platelet reactivity was significantly increased after the CPET compared to rest at the beginning and at the end of the 14-week follow-up (among the intervention groups) by the MEA-ADP and MEA-ASPI tests (p < .01 for all analyses). In post-MI patients on DAPT, 14 weeks of supervised ET did not reduce platelet reactivity. Moreover, platelet reactivity was increased after high-intensity exercise (ClinicalTrials.gov: NCT02958657; https://clinicaltrials.gov/ct2/show/NCT02958657).What is the context? Platelet reactivity is reduced after exercise training in healthy individuals and patients with cardiovascular risk factors, but the effect in higher-risk patients is unknown.High-intensity exercise in untrained individuals increases platelet reactivity. The effect of dual antiplatelet therapy in inhibiting exercise-induced hyperreactivity is poorly understood.What’s new?Exercise training did not reduce platelet reactivity in post-myocardial infarction patients.High-intensity exercise increased platelet reactivity in post-myocardial infarction patients on dual antiplatelet therapy.Exercise training did not attenuate the exercise-induced increase in platelet reactivity.What’s the impact?The study suggests that strenuous exercise, if indicated, should be applied carefully to patients with high risk of recurrent ischemic events, even if on optimal medical therapy and after being trained.