Circulating reticulated platelets over time in patients with myocardial infarction treated with prasugrel or ticagrelor

J Thromb Thrombolysis. 2015 Jul;40(1):70-5. doi: 10.1007/s11239-014-1156-4.

Abstract

Reticulated platelets (RP) are young, hyperactive platelets that are increased during situations of enhanced platelet turnover such as acute myocardial infarction (AMI). The dynamics of RP levels after AMI is not established. We aimed to characterize the levels of circulating RP over time in patients with AMI. Patients with AMI treated with ticagrelor or prasugrel who underwent percutaneous coronary intervention (PCI) were tested for circulating RP using flow cytometry with Thiazole orange staining at 3 time points at 2-4 days, 30-60 days and 1 year post PCI. Platelet reactivity was assessed using the VerifyNow P2Y12 assay at these time points (results in platelet reactivity units-PRU). Thirty-five patients were included in the study (mean age 62.6 ± 9.1 years, 82.9 % males). Median RP levels were similar at the first and second time points (17.5 %, IQR 25-75: 10.8-22.4 % and 14.9 %, IQR 25-75: 9.7-26.8 %, respectively; p = 0.75). However, RP levels after 1 year were significantly lower as compared to the first and second time points (10.5 % (IQR 25-75: 5.3-18.1 %), p = 0.005 and p = 0.01, respectively). Residual platelet reactivity was very low at all 3 time points (median PRU 25, IQR 25-75: 7-53) and did not change significantly between them (p = 0.66). No significant correlation was found between levels of RP and PRU at any given time point. RP levels of patients with AMI treated with prasugrel or ticagrelor decrease over time after the acute event. However, RP levels over time do not correlate well with residual platelet reactivity.

MeSH terms

  • Adenosine / analogs & derivatives*
  • Adenosine / pharmacology
  • Adenosine / therapeutic use
  • Aged
  • Blood Platelets / drug effects*
  • Blood Platelets / metabolism
  • Cohort Studies
  • Female
  • Humans
  • Male
  • Middle Aged
  • Myocardial Infarction / blood*
  • Myocardial Infarction / drug therapy*
  • Platelet Activation / drug effects*
  • Platelet Activation / physiology
  • Platelet Aggregation Inhibitors / pharmacology
  • Platelet Aggregation Inhibitors / therapeutic use
  • Platelet Function Tests / methods
  • Prasugrel Hydrochloride / pharmacology
  • Prasugrel Hydrochloride / therapeutic use*
  • Prospective Studies
  • Purinergic P2Y Receptor Antagonists / pharmacology
  • Purinergic P2Y Receptor Antagonists / therapeutic use
  • Ticagrelor
  • Time Factors
  • Treatment Outcome

Substances

  • Platelet Aggregation Inhibitors
  • Purinergic P2Y Receptor Antagonists
  • Prasugrel Hydrochloride
  • Ticagrelor
  • Adenosine