Abstract Number: PB1393
Meeting: ISTH 2020 Congress
Background: Platelet function tests allow identification of poor responders to the antiaggregant clopidogrel, who are exposed to a higher risk for cardiovascular events. Light transmission aggregometry (LTA) is regarded as the golden standard method, however, with several drawbacks that can be overcome by the INNOVANCE PFA P2Y test.
Aims: We evaluated the inter-assay variability between both tests to detect clopidogrel resistance.
Methods: Results of 106 patients on clopidogrel treatment were compared between LTA Chronolog 700 platelet aggregometry (Chronolog) and PFA P2Y performed on INNOVANCE® PFA-200 (Siemens Healthcare). Responsiveness to clopidogrel was defined as a peak aggregation < 50% and/or disaggregation >20% after adding 2.5 µM and/or 5 µM ADP for LTA and a closure time (CT) of >113 seconds for PFA P2Y. All patients classified as clopidogrel non-responders by LTA were genotyped for CYP2C19.
Results: For PFA P2Y, a clopidogrel effect was observed in 72% of the samples compared to 85% using LTA. In total, 18/106(17%) discrepancies were reported between both methods. In 16/18(89%) of discrepant cases, a normal CT was obtained with PFA P2Y, classifying a higher number of patients as clopidogrel resistant. In 2/18(11%) cases, a prolonged CT was found with PFA P2Y, thus potentially missing clopidogrel resistance. One of these patients was a heterozygote carrier of the CYP2C19*2 variant allele (intermediate clopidogrel metabolizer). Overall, our results showed a moderate comparability of PFA P2Y to LTA.
Conclusions: PFA P2Y is insufficiently sensitive to detect a clopidogrel effect compared to Chronolog 700 LTA and may additionally miss clopidogrel non-responding CYP2C19*2 carriers.
To cite this abstract in AMA style:Heireman L, Devreese K. Detection of Clopidogrel Resistance: Comparison of Light Transmission Aggregometry and INNOVANCE® PFA P2Y Cartridge and Correlation with CYP2C19 Variants [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/detection-of-clopidogrel-resistance-comparison-of-light-transmission-aggregometry-and-innovance-pfa-p2y-cartridge-and-correlation-with-cyp2c19-variants/. Accessed January 21, 2022.
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