Characterization of the antiplatelet effect of aspirin at enrollment and after 2-year follow-up in a real clinical setting in Japan.
BACKGROUND
Aspirin is an antiplatelet drug widely used for the prevention of cardiovascular diseases. It has been reported that some patients who exhibit a reduced antiplatelet effect of aspirin have higher cardiovascular risk. It is still controversial whether the antiplatelet effect of aspirin diminishes after a few years of treatment. This study aimed to evaluate the antiplatelet effect of aspirin and its 2-year change in Japanese patients.


RESULTS
Collagen-induced platelet-aggregability was measured at enrollment by conventional optical aggregometer in 239 patients undergoing antiplatelet therapy with aspirin alone. Among them, 167 patients were evaluated after 2 years. Whole blood aggregability based on the screen-filtration method was also evaluated. Optical aggregometer studies showed that 27% of patients were low-responders. Multivariate analyses revealed that female sex and non-use of calcium-channel blockers were associated with low responsiveness. The antiplatelet effect of aspirin did not decrease after 2 years. Similar data were obtained with the whole blood aggregometer.


CONCLUSIONS
In this Japanese patient group, 27% were low-responders to aspirin, and the antiplatelet effect of aspirin did not decrease after a 2-year interval.
Ikeda
Tomoyuki
T
Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Taniguchi
Ryoji
R
Watanabe
Shin
S
Kawato
Mitsunori
M
Kondo
Hirokazu
H
Shirakawa
Ryutaro
R
Yamane
Keiichiro
K
Toma
Masanao
M
Tamura
Toshihiro
T
Takahashi
Kanako
K
Watanabe
Haruyo
H
Yoshikawa
Yuka
Y
Tabuchi
Arata
A
Kita
Toru
T
Kimura
Takeshi
T
Horiuchi
Hisanori
H
D000368:Aged; D001241:Aspirin / Q000493:pharmacokinetics / Q000494:pharmacology*; D001780:Blood Coagulation Tests; D002121:Calcium Channel Blockers / Q000494:pharmacology; D003094:Collagen / Q000494:pharmacology; D004351:Drug Resistance / Q000187:drug effects; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D010975:Platelet Aggregation Inhibitors / Q000493:pharmacokinetics / Q000494:pharmacology*; D010979:Platelet Function Tests; D012737:Sex Factors; D013997:Time Factors
D002121:Calcium Channel Blockers; D010975:Platelet Aggregation Inhibitors; D003094:Collagen; D001241:Aspirin