Background: Response to clopidogrel is characterized by wide variability and high rates of high on treatment platelet reactivity (HTPR). Recent studies have shown that HTPR exists, with the use of prasugrel as well, although to a lesser extent, and that HTPR is associated with an increased risk of MACE after percutaneous intervention (PCI). We have recently shown that the proportion of circulating young reticulated platelets (RPs) inversely correlates with responsiveness to both clopidogrel and prasugrel. The aim of the current study is to examine the variability in response to ticagrelor, and the correlation with levels of circulating RPs.
Methods: Patients with non ST elevation MI (NSTEMI) treated with PCI and ticagrelor were tested for platelet reactivity using the VerifyNow P2Y12 assay and the Multiplate analyzer. RPs levels were determined using flow cytometry with Thiazole Orange staining. Tests were performed at 2-4 days and 30 days post-PCI.
Results: 53 patients were included (mean age 62.6±9.8 years, 18.9% women, 36.5% diabetes).
The variability in response to ticagrelor was very low according to both the Verifynow and multiplate assays, with no cases of HTPR at either time-points. In addition, there were no differences in platelet reactivity, as analyzed by the VerifyNow P2Y12 assay, or in the proportion of RPs between the two time points. With the multiplate analyzer a small increase in platelet reactivity between the first and second time points was observed (8.6±6 AU vs. 15.5±11AU, p=0.001).
Importantly, there was no significant correlation between platelet reactivity and RPs at either time point.
Conclusion: Variability in the response to ticagrelor in patients with NSTEMI undergoing PCI is very low, with no cases of HTPR. There was no correlation between platelet reactivity and the proportion of RPs, presumably as a result of this very low variability.
