Determinants of High and Low Platelet Residual Reactivity on Day 1-2 of Myocardial Infarction When Taking Clopidogrel

Abstract

The aim of the study was to determine the clinical and laboratory factors that determine high and low platelet reactivity in patients taking clopidogrel on day 1-2 of myocardial infarction (MI). Material and Methods. A total of 405 patients (322 men and 83 women) with MI aged 31 to 74 years were examined. Group 1 included patients with low residual platelet reactivity (LRPR) – 89 people, group 2 consisted of patients with optimal platelet reactivity (OPR) – 223 people, group 3 was composed of patients with high residual platelet reactivity (HRPR) – 93 people. Platelet aggregation was assessed on a Multiplate impedance aggregometer (Germany) with several aggregation inducers. A blood test and a study of morphometric parameters of platelets were performed by the cytoflow method on an automated hematology analyzer Sysmex XS-500i (Japan). The study of the level of soluble CD40 ligand (sСD40L) and sP-selectin was performed in 140 patients, von Willebrand factor (VWF) and endothelin-1 were assessed in 150 people on the enzyme immunoassay analyzer Sunrise (TECAN, Austria) using Fine Biotech kits (China). All studies were performed upon admission to the hospital on day 1-2 of MI (at least 12 hours after the administration of a loading dose of clopidogrel). Results. A one-way linear regression analysis identified the following factors that independently affect the value of the ADP-test: age (β=-0.21, 95% CI: -0.42 – -0.0095; p=0.04); total cholesterol (β=1.4, 95% CI: 0.26–2.56; p=0.04); white blood cell count (β= 0.57, 95% CI: 0.003–1.14; p=0.049); hemoglobin (β=-0.16, 95% CI: -0.27 – -0.044; p=0.0067); platelet count (β=1.4, 95% CI: 0.26 – 2.56; p=0.04); PCT (β=76.8, 95% CI: 41.5 – 112.1; p=0.000024); TRAP-test (β=0.4, 95% CI: 0.33–0.46; p<0.000001); CD40L (β=0.044, 95% CI: 0.013–0.074; p=0.005); sP-selectin (β=2.3, 95% CI: 0.63 – 3.97; p=0.007); VWF (β=0.06, 95% CI: 0.016 – 0.11; p=0.0085). To determine the probability of HRPR developing a binary logistic regression model was constructed based on the observational data of a sample of 398 patients, which included the following indicators: age, white blood cell count, mean platelet volume (MPV) and platelet distribution width (PDW) values, results of TRAP-test and the level of creatinine. At the probability cut-off p=0.4746, the sensitivity of the constructed model was 74.2%, specificity - 74.1%, classification accuracy – 74.1%, the area under the ROC-curve – 0.795 (CI: 0.745 – 0.844). To determine the probability of developing LRPR, a binary logistic regression model was constructed based on the observational data of 143 patients, which included the following indicators: the number of leukocytes, MPV and TRAP-test values, fibrinogen and VWF levels. With a probability cut-off p=0.5589, the sensitivity of this model was 84.6%, specificity – 77.8%, classification accuracy – 79.0%, the area under the ROC-curve – 0.826 (CI: 0.747 – 0.905). Conclusion. On days 1-2 of MI, 22% of patients with an excessive response to clopidogrel and 23% with an insufficient response to clopidogrel were identified. The determinants of HRPR are age, white blood cell count, MPV, PDW, TRAP-test and creatinine levels. The determinants of LRPR are white blood cell count, MPV values, spontaneous platelet aggregation, detected by the TRAP-test, the level of fibrinogen and VWF.