Abstract 9486: Different Influences of Hematocrit on the Results of Two Point-of-Care Platelet Function Tests, the VerifyNow Assay and Multiple Electrode Platelet Aggregometry
Introduction: Previous studies have reported a considerable association between the VerifyNow (Accumetrics, San Diego, CA, USA) P2Y12 assay results and hematocrit. No reports, however, have described an association between the multiple electrode platelet aggregometry (MEA; Dynabyte, Munich, Germany) adenosine diphosphate (ADP) assay results and hematocrit.
Methods: A total of 462 consecutive patients who were undergoing percutaneous coronary intervention were enrolled. Platelet function was evaluated with both the VerifyNow P2Y12 and MEA ADP assays.
Results: Anemic patients (n=152, 32.9%) demonstrated a significantly higher rate of cardiac death, myocardial infarction, and stroke (5.3% vs. 2.3%, p=0.046) during the follow-up (median: 18.8 months). Although the VerifyNow P2Y12 assay results demonstrated a significant inverse correlation with hematocrit (r=-0.409, p<0.001, Figure 1-A), there was no such correlation between the MEA ADP assay results and hematocrit (r=0.039, p=0.401, Figure 1-B). Anemic patients had a significantly higher P2Y12 reaction unit (PRU) value than non-anemic patients (p<0.001, Figure 1-C). There was no significant difference between non-anemic and anemic patients in terms of the MEA ADP assay results (p=0.548; Figure 1-D). In the multivariate analysis, anemia was an independent predictor of high on-treatment platelet reacrivity, defined as a PRU value of ≥252.5 (OR=2.21, 95% CI=1.39-3.52; p=0.001). Importantly, this association was independent of an intrinsic change in platelet reactivity as measured by the MEA ADP assay. Adjusting for the influence of hematocrit improved the strength of the correlation between the VerifyNow P2Y12 and MEA ADP assay results.
Conclusions: Hematocrit significantly influenced the VerifyNow P2Y12 assay results, a phenomenon that was presumably in-vitro. Hematocrit level should therefore be considered when interpreting results of the VerifyNow P2Y12 assay.
Author Disclosures: Y. Kim: None. J. Suh: None. J. Park: None. I. Oh: None. C. Yoon: None. Y. Cho: None. T. Youn: None. I. Chae: None. D. Choi: None.
- © 2014 by American Heart Association, Inc.