Measurement of the platelet retention rate in a column of collagen-coated beads is useful for the assessment of efficacy of antiplatelet therapy.
BACKGROUND
A simple, validated method to measure platelet function is unavailable for bedside use. Measurement of platelet retention rate using a column of collagen-coated beads and whole blood is a new, simple assay that reflects platelet aggregation. This study was aimed to examine the utility of this assay to assess efficacy of antiplatelet drug therapy.


METHODS
Citrated whole blood (1.5 ml) in a syringe was passed through a polyvinyl tube packed with collagen-coated beads for 40 seconds using a syringe pump. Platelet retention rate in the column was calculated from platelet counts in blood before and after passage. An increase in the retention rate reflects an increase in platelet activity. This new platelet retention assay and the traditional optical aggregometry assay were performed in 331 patients with stable coronary artery disease (CAD).


RESULTS
The retention rate was significantly reduced in patients taking dual antiplatelet therapy (aspirin plus clopidogrel or ticlopidine) compared with aspirin alone. There was a significant linear correlation between the platelet retention rate and platelet aggregability measured by the traditional method (r=0.44, p<0.001). In multivariate Cox proportional hazards analysis, higher platelet retention rate was an independent predictor of future cardiovascular events in patients on dual antiplatelet therapy (hazard ratio 3.9, 95% CI 1.6 to 9.5, p=0.003).


CONCLUSIONS
Measurement of the platelet retention rate in a column of collagen-coated beads may be useful for monitoring the efficacy of antiplatelet drug therapy in patients with CAD.
Mende
Akira
A
Department of Internal Medicine II, University of Yamanashi, Chuo city, Yamanashi prefecture, Japan.
Obata
Jyun-Ei
JE
Sano
Keita
K
Hirano
Mitsumasa
M
Kitta
Yoshinobu
Y
Kodama
Yasushi
Y
Nakamura
Takamitsu
T
Kawabata
Ken-Ichi
K
Saitoh
Yukio
Y
Fujioka
Daisuke
D
Kobayashi
Tsuyoshi
T
Satoh
Kaneo
K
Ozaki
Yukio
Y
Yano
Toshiaki
T
Kugiyama
Kiyotaka
K
D000368:Aged; D001241:Aspirin / Q000627:therapeutic use; D001792:Blood Platelets / Q000166:cytology* / Q000187:drug effects*; D002469:Cell Separation; D000077144:Clopidogrel; D003094:Collagen; D003324:Coronary Artery Disease / Q000097:blood / Q000188:drug therapy; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use*; D010979:Platelet Function Tests / Q000295:instrumentation / Q000379:methods*; D013988:Ticlopidine / Q000031:analogs & derivatives / Q000627:therapeutic use; D016896:Treatment Outcome
D010975:Platelet Aggregation Inhibitors; D003094:Collagen; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin