Background:
Platelets newly released from the bone marrow are characterized by large cell volumes and, contrary to mature platelets, contain RNA, which might reflect an increased capacity of producing proaggregatory proteins. We hypothesized that the fraction of RNA-containing, immature platelets (Immature Platelet Fraction = IPF) is a marker for acute coronary thrombus formation.
Methods:
Flow cytometric determination of immature platelets was conducted using a RNA fluorescent dye and an automated analyzer (Sysmex XE-2100). Measurements were performed in a total of 426 individuals (365 patients with acute coronary syndromes (ACS), 39 patients with stable coronary artery disease (CAD) and 22 healthy individuals).
Results:
Geometric mean IPF was 2.5 (CV = 0.37) in the control group, 2.9 (0.43) in patients with stable CAD, 3.0 (0.55) in the non-STEMI/Unstable Angina group and 3.7 (0.56) in patients with STEMI. IPF was significantly increased in STEMI patients compared to all other groups (t-test for log-transformed data: p < 0.004), and the overall difference between groups was significant (ANOVA: p < 0.0001). IPF was increased in active smokers among patients with ACS (3.2 vs 3.6, p=0.02), whereas no relation with age, sex, body mass index or CRP levels was observed.
Conclusion:
The fraction of RNA-containing platelets is increased in ACS, especially in the acute phase of STEMI. Immature platelets with an increased haemostatic potential may contribute to coronary thrombus formation and may partly explain previous findings of temporary resistance to anti-platelet therapy.
Oxidized LDL and Malondialdehyde-Modified LDL in Patients With Acute Coronary Syndromes and Stable Coronary Artery Disease
