The Methodological Evaluation Of Different Methods For Monitoring Anti-platelet Therapy In Clinical Laboratory

Objective The aim of this study was to make a methodological evaluation bycomparing different platelet function testing methods when monitor antiplatelet therapyin clinical laboratory. Meanwhile we evaluated the clincal value of a new developedplatelet function assay PL-11.Methods○1Platelet function was measured to monitor short-term aspirin or clopidogrelresponse in20healthy young men, using PL-11, light transmittance aggregometry(LTA), VerifyNow and thromboelastography (TEG).○2Set ADP induced lighttransmittance as the standard and compared platelet function changes before and afterclopidogrel intake in25healthy subjects with50mmol/L ADP and2mg/L collagen.○345young healthy subjects and26coronary artery disease (CAD) patients takingclopidogrel as the only antiplatelet drug in our hospital in2012year were included.Platelet function of all subjects was performed with LTA and PL-11within2hours.Results○1Aspirin response: Correlations between arachidonic acid (AA) inducedPL-11and other methods were: LTA,0.614; VerifyNow,0.829; TEG,0.697,respectively. Biases between AA-PL-11and AA-LTA were1.94%at baseline and-24.02during aspirin treatment. Cut-off value for PL-11of low aspirin responseobtained with ROC analysis was33.3%. Clopidogrel response: Correlations betweenADP induced PL-11and other methods were: LTA,0.757; VerifyNow,0.851; TEG,0.608. Biases between ADP-PL-11and ADP-LTA were3.01%at baseline and6.56%during clopidogrel therapy. Cut-off value for PL-11of low clopidogrel responseobtained with ROC analysis was66%.○2The baseline reference range of collageninduced PL-11was (64.7-83.6)%(95%PI), ADP induced PL-11was (67.2-86.8)%(95%PI). We defined the “low clopidogrel response” as the reduction of ADP inducedLTA<10%after exposure of clopidogrel. Cut-off values for ADP-PL-11and Col-PL-11were obtained with ROC analysis: ADP-PL-11,66%(sensitivity84.6%，specificity 88.2%); Col-PL-11,60.0%(sensitivity69.2%，specificity70.6%).○3Both LTA andPL-11were able to detect the statically significant difference between healthy controlgroup and clopidogrel treatment group results. ADP induced LTA and PL-11had amoderate correlation when monitoring clopidogrel response (r=0.616, p<0.001) and thebias between LTA and PL-11was-9.3%.Conclusion○1Results of different platelet function testing methods were not equallyeffective. LTA still is the classical method when monitor antiplatelet therapy.VerifyNow had a good ability in antiplatelet monitoring. TEG could reflect aspirintherapy but when monitoring clopidogrel treatment, TEG had a high false negative.PL-11had a high agreement with LTA when monitor clopidogrel therapy or the basicvalues.○2ADP had a higher sensitivity and specificity than collagen in monitoringclopidogrel short-response tested with PL-11.○3ADP induced PL-11correlated wellwith the golden standard LTA when evaluating clopidogrel response in patients,showing that continuous platelet count method based PL-11may be an alternate choicefor laboratory when monitoring platelet function. PL-11is considered as an alternativemethod of LTA.