Onset and extent of platelet inhibition by clopidogrel loading in patients undergoing elective coronary stenting: the Plavix Reduction Of New Thrombus Occurrence (PRONTO) trial.

Background: Despite the common practice of clopidogrel loading for coronary stenting, the time dependence and degree of platelet inhibition after this therapy are not well defined. We sought to establish an optimal clopidogrel dosing regimen for sustained platelet inhibition in stented patients.

Methods And Results: Platelets were assessed by conventional aggregation with 5 micromol/L adenosine diphosphate (ADP), 1 microg/mL collagen (COLL), and 750 micromol/L arachidonic acid; whole blood aggregation by 1 microg/mL collagen (WBA); shear-induced closure time (CT); contractile force (CF); and expression of 9 surface receptors by flow cytometry in 100 patients undergoing elective stent placement without glycoprotein (GP) IIb/IIIa receptor antagonists.

Failure of platelet parameters and biomarkers to correlate platelet function to severity and etiology of heart failure in patients enrolled in the EPCOT trial. With special reference to the Hemodyne hemostatic analyzer. Whole Blood Impedance Aggregometry for the Assessment of Platelet Function in Patients with Congestive Heart Failure.

Data from small studies have suggested the presence of platelet abnormalities in patients with congestive heart failure (CHF). We sought to characterize the diagnostic utility of different platelet parameters and platelet-endothelial biomarkers in a random outpatient CHF population investigated in the EPCOT ('Whole Blood Impedance Aggregometry for the Assessment of Platelet Function in Patients with Congestive Heart Failure') Trial. Blood samples were obtained for measurement of platelet contractile force (PCF), whole blood aggregation, shear-induced closure time, expression of glycoprotein (GP) IIb/IIIa, and P-selectin in 100 consecutive patients with CHF.