Point of Care Tests VerifyNow P2Y12 and INNOVANCE PFA P2Y Compared to Light Transmittance Aggregometry After Fibrinolysis

Abstract

Detection of high on-treatment platelet reactivity (HPR) by point-of-care tests has not been validated after successful fibrinolysis for ST-elevation myocardial infarction. We assessed the validity of the point-of-care VerifyNow P2Y12 (VN) and INNOVANCE PFA P2Y (PFA) tests on HPR compared to light transmittance aggregometry (LTA) in these patients. The HPR was identified in 10 (34.5%) patients, 15 (51.7%) patients, and 14 (50%) patients using LTA, VN, and PFA, respectively. Discrepancies were observed between the tests despite significant correlations between platelet reactivity measures by LTA and VN ( r = 0.74; P < .0001) and LTA and PFA ( r = .75; P < .0001). Compared to LTA, VN and PFA were associated with a 92% and 53% and 92% and 64% positive predictive value (PPV) and negative predictive value (NPV), respectively, in detecting HPR. When combined, VN and PFA results yielded 90% and 100% PPV and NPV values if discrepancies between the 2 tests were considered as non-HPR. The VN or PFA identify patients without HPR correctly but overestimate the proportion of HPR patients. The association of the 2 tests, in case of HPR, improves the accuracy of the detection of HPR.

Keywords: ST-segment elevation myocardial infarction; clopidogrel; fibrinolysis; platelet aggregation; point-of-care testing.

Figure 1.

Distribution and correlation of values derived from measurements between (A) LTA (inhibition of platelet aggregation, %) and VN (PRU), (B) LTA and PFA (closure time, seconds), and (C) PFA and VN. The lines indicate the cutoff values of each test determining high platelet reactivity (106 seconds for PFA, 208 PRU for VN, and 30% for LTA). PFA indicates INNOVANCE PFA P2Y; PRU, P2Y12 reaction units; VN, VerifyNow.

Figure 2.

Responsiveness status of the patients at the time of angiography and day + 1 based on VerifyNow P2Y12.