Search

Introduction: Platelet hyper-reactivity, despite a standard anti-thrombotic therapy, is a recognized risk factor for recurrent myocardial ischemia and in-stent thrombosis following PCI. We have investigated whether this detrimental condition, measured by collagen-epinephrine closure times (CEPI-CT) with the Platelet Function Analyzer (PFA-100) device could predict IST defined as the composite of cardiovascular death or myocardial infarction., Materials and Methods: CEPI-CT was measured in 256 consecutive patients with stable angina (n=103) or ACS (n=153) 30+/-8 h after PCI (T 0) and 1 month later (T1). All patients were followed up for a mean period of 9 months. Platelet hyperactivity was defined as a CEPI-CT<190 s., Results: Baseline CEPI-CT<190 s was associated with a higher rate of death or MI (LogRank chi2=4.23, p=0.039) as compared with CEPI-CT>190 s (4.6% vs. 0.7%). Multivariable analysis after adjustment for other risk factors confirmed that baseline CEPI-CT<190 s was an independent correlate for death or MI (Hazard ratio 6.981, p=0.008). At T1 there was a significant prolongation of CEPI-CT (p=0.03) from 208+/-64 s to 240+/-59 s but T1 did not predict any event., Conclusions: A CEPI-CT<190 s measured within the first 24 h following PCI predicts IST defined as the occurrence of death or MI.

Introduction: An increasing amount of evidence indicates that platelet reactivity, despite a standard anti-thrombotic therapy, is a potential risk factor for recurrent myocardial ischemia in patients with coronary artery disease. We now hypothesize that this condition, measured by collagen-epinephrine (CEPI) or collagen-ADP (CADP) closure times (CT) by Platelet Function Analyzer (PFA-100), may predict the recurrence of coronary events after percutaneous coronary intervention (PCI)., Materials and Methods: CEPI and CADP-CT were measured 30+/-8 h after PCI in 175 consecutive patients admitted with a diagnosis of stable angina (n=94) or acute coronary syndromes (n=81) and prospectively followed up for a mean period of 6 months. We stratified the patients in accordance to both the CEPI-CT ( 190 s), reflecting the intensity of cycloxygenase inhibition by aspirin and the distribution into quartiles for CADP-CT., Results: CEPI-CT<190 s as well as CADP-CT<82 s were associated with a higher rate of clinical recurrence (hazard ratio 8.5, p<0.001 and 22.9, p<0.001, respectively). Multivariate analysis after adjustment for other risk factors confirmed that the lowest CADP-CT quartile significantly correlates with the risk of recurrent coronary events (hazard ratio 36.5, p<0.01), as well as CEPI-CT<190 s (hazard ratio 6.7, p=0.01)., Conclusions: An enhanced platelet function after PCI when measured under high shear rates by PFA-100 is an independent predictor of a worst clinical outcome, even during a short term follow-up and may help in patients risk stratification.

In this study F-actin polymerization in neutrophils from 21 patients affected by myelodysplastic syndromes (MDS) was evaluated by means of a flow cytometric assay. Neutrophils were stimulated with formyl-methionyl-leucyl-phenylanaline (fMLP; 10(-8) M final concentration) for 15, 30, 60 and 120 sec, and F-actin content was determined using fluorescein-isothiocyanate phallacidin as a specific probe. Eight normal subjects were studied as controls. We found that F-actin polymerization was defective in ten patients, with very impaired values after 60 and 120 sec of stimulation with fMLP. The remaining 11 patients showed a prevalent neutrophil population with normal F-actin polymerization and neutrophil sub-populations with either defective or undetectable F-actin polymerization. In the first group, patients with very poor prognosis (refractory anemia with excess blasts, refractory anemia with excess blasts in leukemic transformation, trisomy 8, multiple karyotypic abnormalities) were present, although patients with aberrations of karyotype were present in the second group. It is possible that defects in neutrophil F-actin polymerization may be responsible for neutrophil dysfunction, which has frequently been observed in MDS.