Platelet Reactivity and Endothelial Function in Children of Patients With Early Acute Myocardial Infarction

Study Questions:

Is there an increase in platelet reactivity in offspring of patients with early acute myocardial infarction (AMI), and does it have a relation with endothelial dysfunction?

Methods:

The investigators studied 23 healthy children (15 ± 3 years, 13 males) of patients with early AMI (≤50 years old; group 1) and 21 healthy children of healthy subjects without any history of cardiovascular disease (14 ± 3 years, 10 males; group 2). Platelet reactivity was assessed by flow cytometry as the increase in monocyte-platelet aggregates (MPA) and CD41 and PAC-1 platelet expression in response to exercise stress test (EST), adenosine diphosphate (ADP) stimulation (10-7 M), or both. Endothelial function was assessed by measuring brachial artery dilation during post-ischemic forearm hyperemia (flow-mediated dilation [FMD]).

Results:

Both EST and ADP induced a higher percentage increase in platelet receptor expression in group 1, compared with group 2, with the most significant difference being shown for the response to the combined stimuli (e.g., MPA, 23.1 ± 12 vs. 5.63 ± 8%, p < 0.001; platelet PAC-1, 57.7 ± 47 vs. 13.2 ± 7%, p < 0.001). Compared with group 2, group 1 children showed lower FMD (10.7 ± 3.1 vs. 8.0 ± 2.9%, respectively; p = 0.007). However, no significant association was found between FMD and platelet reactivity.

Conclusions:

The authors concluded that there is increased platelet reactivity in children of patients with early AMI.

Perspective:

This study suggests that children of patients with early AMI display an increased platelet reactivity in response to agonistic stimuli such as ADP and EST, in particular when combined. The results also confirm the presence of impaired endothelial function in these children, but no correlation could be demonstrated between endothelial dysfunction and increased platelet reactivity, suggesting that they are likely largely related to independent mechanisms. Whether the findings help explain the increased risk of cardiovascular events in adults with a family history of premature coronary disease requires further study.

Clinical Topics: Vascular Medicine

Keywords: Flow Cytometry, Myocardial Infarction, Cardiology, Vascular Diseases, Cardiovascular Diseases, Coronary Disease, Blood Platelets, Hyperemia, Exercise Test


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