A comparison of VerifyNow-P2Y12 Assay and light transmission aggregometry in detecting antiplatelet function of clopidogrel in elderly patients after percutaneous coronary intervention

Objective To analyze the correlation between the testing results of VerifyNow-P2Y12 Assay and light transmission aggregometry(LTA)in elderly patients treated with clopidogrel following percutaneous coronary intervention(PCI)and to compare the sensitivity of the two methods in predicting clinical ischemic events.Methods A total of 160 elderly patients(60 years old and above)who underwent PCI and had taken clopidogrel at least for 7 days were enrolled in the study.Their adenosine diphosphate(ADP)-induced platelet aggregative function was tested by both VerifyNow-P2Y12 and LTA.High on-treatment platelet reactivity(HPR) was defined as 5 μmol/L ADP induced maximal platelet aggregation(MPAR)≥46%in LTA and P2Y12 reaction units(PRU)≥230 in VerifyNow-P2Y12 Assay.The correlation between results of the two assays was analyzed by bivariate correlation analysis and linear regression.All the patients had been followed up for at least 6 months.Thesensitivity of HPRs measured by the two different assays in predicting clinical ischemic events was compared. Results HPR was found in 44(27.5%) patients by VerifyNow-P2Y12 and in 52(32.5%) patients by LTA(P 0.05).MPAR was positively related to PRU(r=0.62315,P=0.037).The linear regression equation was Y(VerifyNow-P2Y12)=2.015 X(LTA)+110.2.The incidence of clinical ischemic events in VerifyNow-HPR group was significantly higher than that in non VerifyNow-HPR group(27.1% vs.6.0%,OR=6.53,95% CI:2.61- 16.32,P=0.000).But there was no significant difference in the incidence of clinical ischemic events between LTA-HPR group and non LTA-HPR group(17.2% vs.9.3%,OR=2.33,95% CI:0.92-5.91,P=0.074). Conclusion Both VerifyNow-P2Y12 Assay and LTA are effective in identifying HPR in the elderly patients treated with clopidogrel after PCI.The incidence of clinical ischemic events in the patients with HRP is significantly higher than that in the patients without HRP.Compared with LTA,VerifyNow-P2Y12 Assay has higher sensitivity in predicting clinical ischemic events during clopidogrel therapy in elderly patients.