TY - JOUR
T1 - Comparison of VerifyNow-P2Y12 test and flow cytometry for monitoring individual platelet response to clopidogrel. What is the cut-off value for identifying patients who are low responders to clopidogrel therapy?
AU - Godino, Cosmo
AU - Mendolicchio, Loredana
AU - Figini, Filippo
AU - Latib, Azeem
AU - Sharp, Andrew S.P.
AU - Cosgrave, John
AU - Calori, Giliola
AU - Cera, Michela
AU - Chieffo, Alaide
AU - Castelli, Alfredo
AU - Maseri, Attilio
AU - Ruggeri, Zaverio M.
AU - Colombo, Antonio
PY - 2009/5/6
Y1 - 2009/5/6
N2 - Background: Dual anti-platelet therapy with aspirin and a thienopyridine (DAT) is used to prevent stent thrombosis after percutaneous coronary intervention (PCI). Low response to clopidogrel therapy (LR) occurs, but laboratory tests have a controversial role in the identification of this condition. Methods: We studied LR in patients with stable angina undergoing elective PCI, all on DAT for at least 7 days, by comparing: 1) Flow cytometry (FC) to measure platelet membrane expression of P-selectin (CD62P) and PAC-1 binding following double stimulation with ADP and collagen type I either in the presence of prostaglandin (PG) E1; 2) VerifyNow-P2Y12 test, in which results are reported as absolute P2Y12-Reaction-Units (PRU) or % of inhibition (% inhibition). Results: Thirty controls and 52 patients were analyzed. The median percentage of platelets exhibiting CD62P expression and PAC-1 binding by FC evaluation after stimulation in the presence of PG E1 was 25.4% (IQR: 21.4-33.1%) and 3.5% (1.7-9.4%), respectively. Only 6 patients receiving DAT (11.5%) had both values above the 1st quartile of controls, and were defined as LR. Evaluation of the same patients with the VerifyNow-P2Y12 test revealed that the area under the receiver-operating-characteristic (ROC) curve was 0.94 (95% CI: 0.84-0.98, p < 0.0001) for % inhibition and 0.85 (0.72-0.93, p < 0.005) for PRU. Cut-off values of ≤ 15% inhibition or 213 PRU gave the maximum accuracy for the detection of patients defined as having LR by FC. Conclusion: In conclusion our findings show that a cut-off value of ≤ 15% inhibition or 213 PRU in the VerifyNow-P2Y12 test may provide the best accuracy for the identification of patients with LR.
AB - Background: Dual anti-platelet therapy with aspirin and a thienopyridine (DAT) is used to prevent stent thrombosis after percutaneous coronary intervention (PCI). Low response to clopidogrel therapy (LR) occurs, but laboratory tests have a controversial role in the identification of this condition. Methods: We studied LR in patients with stable angina undergoing elective PCI, all on DAT for at least 7 days, by comparing: 1) Flow cytometry (FC) to measure platelet membrane expression of P-selectin (CD62P) and PAC-1 binding following double stimulation with ADP and collagen type I either in the presence of prostaglandin (PG) E1; 2) VerifyNow-P2Y12 test, in which results are reported as absolute P2Y12-Reaction-Units (PRU) or % of inhibition (% inhibition). Results: Thirty controls and 52 patients were analyzed. The median percentage of platelets exhibiting CD62P expression and PAC-1 binding by FC evaluation after stimulation in the presence of PG E1 was 25.4% (IQR: 21.4-33.1%) and 3.5% (1.7-9.4%), respectively. Only 6 patients receiving DAT (11.5%) had both values above the 1st quartile of controls, and were defined as LR. Evaluation of the same patients with the VerifyNow-P2Y12 test revealed that the area under the receiver-operating-characteristic (ROC) curve was 0.94 (95% CI: 0.84-0.98, p < 0.0001) for % inhibition and 0.85 (0.72-0.93, p < 0.005) for PRU. Cut-off values of ≤ 15% inhibition or 213 PRU gave the maximum accuracy for the detection of patients defined as having LR by FC. Conclusion: In conclusion our findings show that a cut-off value of ≤ 15% inhibition or 213 PRU in the VerifyNow-P2Y12 test may provide the best accuracy for the identification of patients with LR.
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U2 - 10.1186/1477-9560-7-4
DO - 10.1186/1477-9560-7-4
M3 - Article
C2 - 19419580
AN - SCOPUS:66149114859
SN - 1477-9560
VL - 7
JO - Thrombosis Journal
JF - Thrombosis Journal
M1 - 4
ER -