TY - JOUR
T1 - Clopidogrel anti-platelet effect
T2 - An evaluation by optical aggregometry, impedance aggregometry, and the Platelet Function Analyzer (PFA-100™)
AU - Dyszkiewicz-Korpanty, Anna
AU - Olteanu, Horatiu
AU - Frenkel, Eugene P.
AU - Sarode, Ravindra
N1 - Funding Information:
This work was supported by the Raymond D. Nasher Research Foundation. We thank the personnel in the Special Coagulation/Bone Marrow Laboratory and Laboratory Central, Parkland Health and Hospital Systems, for excellent technical support.
PY - 2007/11
Y1 - 2007/11
N2 - Platelet aggregation inhibition by clopidogrel may be suboptimal in 4-30% of patients. Traditionally, optical aggregometry is used to assess clopidogrel's anti-platelet effects by inhibition of ADP-induced aggregation in platelet rich plasma. Red blood cells are an important source of ADP and, thus, are known to modulate platelet function. Because the whole blood aggregation by impedance method assesses platelet function in a physiological milieu, we compared clopidogrel response by this method with the optical method in platelet rich plasma (PRP) and the Platelet Function Analyzer (PFA-100™). Platelet function studies were performed in 17 healthy subjects at baseline and after 10 days of clopidogrel intake (75 mg/day). Optical and impedance aggregometry were performed after addition of ADP (10 and 20 μM) and collagen (1 and 2 μg/mL). For PFA-100™ analysis, whole blood closure time was measured in collagen-coated cartridges with ADP and epinephrine. All subjects except one showed a decrease in ADP-induced aggregation using both aggregation methods. However, ADP-induced platelet aggregation was significantly inhibited when assessed in whole blood as compared to the optical method (71 ± 34% vs. 34.2 ± 23%, p = 0.0002); this suggests that whole blood aggregometry is more sensitive in the detection of clopidogrel effect in the presence of red cells, which are known to modulate platelet function. The PFA-100™ ADP closure time was slightly prolonged above the reference interval in only 5/17 (29%) subjects, suggesting that this instrument is not able to detect clopidogrel effect. We conclude that whole blood aggregation appears to be more sensitive in detecting clopidogrel effect compared with the platelet rich plasma method; the PFA-100™ was unable to detect clopidogrel effect in the majority of the subjects.
AB - Platelet aggregation inhibition by clopidogrel may be suboptimal in 4-30% of patients. Traditionally, optical aggregometry is used to assess clopidogrel's anti-platelet effects by inhibition of ADP-induced aggregation in platelet rich plasma. Red blood cells are an important source of ADP and, thus, are known to modulate platelet function. Because the whole blood aggregation by impedance method assesses platelet function in a physiological milieu, we compared clopidogrel response by this method with the optical method in platelet rich plasma (PRP) and the Platelet Function Analyzer (PFA-100™). Platelet function studies were performed in 17 healthy subjects at baseline and after 10 days of clopidogrel intake (75 mg/day). Optical and impedance aggregometry were performed after addition of ADP (10 and 20 μM) and collagen (1 and 2 μg/mL). For PFA-100™ analysis, whole blood closure time was measured in collagen-coated cartridges with ADP and epinephrine. All subjects except one showed a decrease in ADP-induced aggregation using both aggregation methods. However, ADP-induced platelet aggregation was significantly inhibited when assessed in whole blood as compared to the optical method (71 ± 34% vs. 34.2 ± 23%, p = 0.0002); this suggests that whole blood aggregometry is more sensitive in the detection of clopidogrel effect in the presence of red cells, which are known to modulate platelet function. The PFA-100™ ADP closure time was slightly prolonged above the reference interval in only 5/17 (29%) subjects, suggesting that this instrument is not able to detect clopidogrel effect. We conclude that whole blood aggregation appears to be more sensitive in detecting clopidogrel effect compared with the platelet rich plasma method; the PFA-100™ was unable to detect clopidogrel effect in the majority of the subjects.
KW - Clopidogrel
KW - Optical platelet aggregation
KW - Platelet function
KW - Whole blood impedance aggregation
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U2 - 10.1080/09537100701280654
DO - 10.1080/09537100701280654
M3 - Article
C2 - 17852774
AN - SCOPUS:35648943278
SN - 0953-7104
VL - 18
SP - 491
EP - 496
JO - Platelets
JF - Platelets
IS - 7
ER -