Impact of Routine Platelet Reactivity Testing With VerifyNow Assay on Antiplatelet Choice After Percutaneous Coronary Intervention

Background
High on-treatment ADP platelet reactivity (HPR) is an established risk factor for recurrent ischemic events after Percutaneous Coronary Intervention (PCI). A decrease in clopidogrel bioactivation due to CYP2C19 loss of function genetic variants, as well as other factors influencing intrinsic homeostasis of platelet function contribute to HPR. Point of care platelet testing with VerifyNow P2Y12 assay (VN) can identify clopidogrel ‘non-responders’. We hypothesized that routine use of VN may influence choice of P2Y12 inhibitor therapy in routine clinical practice.

Methods
In a single center retrospective analysis, we examined the influence of VN on choice of P2Y12 inhibitor post PCI in routine clinical practice. All patients undergoing PCI between 2012 and 2018 at Eskenazi Health were included in analysis. Assessment of HPR was used routinely in clinical care during the time period of analysis. Subjects with PRU>208 after loading dose of clopidogrel or during clopidogrel steady state were switched to alternate P2Y12 inhibitors.

Results
We identified 1001 patients with PCI during time period specified. A total 252 subjects underwent VN testing. The majority, 96% had received pre-treatment with clopidogrel. Among those, 38% were found to be non-responders and were switched to alternate therapies (Prasugrel (n=51), Ticagrelor (n=44)). Subjects not undergoing VN assessment were more likely to be discharged on alternate P2Y12 antiplatelet therapy as compared to those who had VN assay done (50% vs 43%, p=0.039). After multivariate adjustment, use of VN in tailoring antiplatelet therapy after PCI was associated with low risk of recurrent 1-year net MACE (CVD, MI, stent thrombosis, BARC 2 or higher bleeding)(Hazard Ratio: 0.81, CI: 0.41-1.47,p=0.48)).

Conclusions
Routine use of VN assay in personalized antiplatelet treatment decision making after PCI is associated with lower likelihood of using novel P2Y12 inhibitors and favorable clinical outcomes