[Impact of application time of aspirin and clopidogrel on platelet aggregation in patients with acute coronary syndrome].
OBJECTIVE
To observe the impact of various application time of aspirin and clopidogrel on the circadian rhythm changes of platelet aggregation in patients with acute coronary syndrome.


METHODS
Patients with acute coronary syndrome were divided into day-time (8:00) and night-time (20:00) medication group (n = 15 each). After plasma concentration reached steady state, platelet aggregation was assessed at 5 time points within 24 hours with a mobile four-channel whole blood impedance aggregometer. The platelet aggregation was induced by ADP and arachidonic acid. Thereafter, the two groups were exchanged and platelet aggregation was assessed in the same way post plasma steady state.


RESULTS
Arachidonic acid-induced platelet aggregation was the highest at 10:00 Am [(7.96 +/- 3.64) ohm] and the lowest at 0:00 [(6.12 +/- 3.29) ohm, P > 0.05] in day-time group. Platelet aggregation was the highest at 20:00 [(9.40 +/- 5.39) ohm] and the lowest at 10:00 [(5.46 +/- 3.93) ohm], P < 0.05). ADP-induced platelet aggregation was the highest at 10:00 and the lowest at 16:00 in day-time group (P > 0.05) and was the highest at 20:00 and the lowest at 10:00 in night-time group (P > 0.05). Platelet aggregation induced by two inducers was significantly higher at 10:00 in day-time group compared to values in night-time group (all P < 0.05).


CONCLUSIONS
Taking aspirin and clopidogrel at 20:00 was superior to taking the same medications at 8:00 for inhibiting peak platelet aggregation in the morning.
Li
Zhen
Z
Department of Cardiology, Second Hospital of Hebei Medical University and Institute of Cardiocerebrovascular Disease of Hebei Province, Shijiazhuang 050000, China.
Liu
Fan
F
Cui
Wei
W
Xie
Rui-qin
RQ
Yang
Xiu-chun
XC
Lu
Jing-chao
JC
Zheng
Hong-mei
HM
Ren
Xiao-juan
XJ
Liu
Jing
J
D054058:Acute Coronary Syndrome / Q000188:drug therapy*; D000328:Adult; D000368:Aged; D001241:Aspirin / Q000008:administration & dosage* / Q000627:therapeutic use; D002940:Circadian Rhythm; D000077144:Clopidogrel; D006801:Humans; D008297:Male; D008875:Middle Aged; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage* / Q000627:therapeutic use; D010979:Platelet Function Tests; D013988:Ticlopidine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000627:therapeutic use; D013997:Time Factors
D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin