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Am Heart J. 2012 Jul;164(1):35-42. doi: 10.1016/j.ahj.2012.03.022. Epub 2012 Jun 13.

Usefulness of the VerifyNow P2Y12 assay to evaluate the antiplatelet effects of ticagrelor and clopidogrel therapies.

Author information

1
Sinai Center for Thrombosis Research, Baltimore, MD, USA.

Abstract

OBJECTIVES:

We analyzed the antiplatelet effects of different P2Y(12) receptor blockers with VerifyNow P2Y12 assay (VN-P2Y12) and light transmittance aggregometry (LTA).

BACKGROUND:

The point-of-care VN-P2Y12 has been used to assess the antiplatelet effects in clopidogrel-treated patients but has not been evaluated in detail in patients treated with ticagrelor.

METHODS:

Patients were randomly assigned to either ticagrelor [180 mg loading/90 mg twice daily (n = 37)] or clopidogrel [600 mg loading/75 mg daily (n = 39)] on top of aspirin treatment, and platelet reactivity was measured serially during onset, maintenance, and offset phases. High on-treatment platelet reactivity (HPR) was defined as 5 and 20 μM adenosine diphosphate-induced maximal platelet aggregation ≥46% and ≥59%, respectively, and P2Y12 reaction units ≥235.

RESULTS:

Platelet function measured by VN-P2Y12 correlated well with LTA (.812 ≤ ρ ≤ .823, P < .001). VN-P2Y12 "BASE" values were consistent during administration of both agents. Calculated and reported percent inhibitions by VN-P2Y12 were similar (difference, -0.6%; 95% agreement limits, -22.9% to 21.6%). Platelet inhibition by VN-P2Y12 during clopidogrel and ticagrelor administrations was comparable to platelet inhibition by LTA. HPR determined by LTA and VN-P2Y12 were well matched, and the risk stratification between the two methods showed strong agreement after both therapies (κ > .7).

CONCLUSIONS:

The VerifyNow P2Y12 assay is effective in assessing the antiplatelet effects and in identifying HPR during clopidogrel or ticagrelor therapy.

TRIAL REGISTRATION:

ClinicalTrials.gov NCT00528411 NCT00642811.

PMID:
22795280
DOI:
10.1016/j.ahj.2012.03.022
[Indexed for MEDLINE]

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