Prevalence of Impaired Platelet Responsiveness to Epinephrine in Healthy Subjects

Choi, Jong Weon; Pai, Soo Hwan

Abstract

BACKGROUND
The purpose of this study is to investigate the prevalence of impaired platelet responsiveness to epinephrine in healthy subjects. Also, we compared the platelet aggregability in response to various agonists in normal population.
METHODS
A total of 156 healthy subjects aged 21 to 57 years were investigated for the evidence of impaired responsiveness to epinephrine. Aggregometer PACKS-4 (Platelet Aggregation Chromogenic Kinetic System-4, Helena, Beaumont, USA) was used for platelet function test. Aggregating agonists (Helena Haemostasis Systems, UK) used in the study were consisted of ADP (10 micrometer), collagen (10 microgram/mL), epinephrine (300 micrometer) and ristocetin (1500 microgram/mL). Population showing platelet aggregability with more than 60% activity was classified as normal group, while aggregability with less than 20% as impaired responsiveness.
RESULTS
Of 156 healthy subjects, 20.5% (32/156) showed impaired responsiveness, while 33.9% (53/156) revealed decreased aggregability with the activity of less than 60% to epinephrine. The mean of maximal percent aggregating activity for collagen was 90.5+/-11.4% and that of epinephrine was 66.5+/-34.4%. The mean aggregation activity (84.4+/-11.8%) for ADP in subjects showing normal response to epinephrine was significantly higher, compared with that (65.7+/-16.2%) of impaired responsiveness group to epinephrine (P<0.01).
CONCLUSION
Impaired responsiveness to epinephrine, which is observed in healthy subjects, appears to be a kind of normal variant reaction. And this abnormality is not considered to be associated with any evident bleeding disorders.