Whole Blood Impedance Aggregometry for the Assessment of Platelet Function in Patients with Congestive Heart Failure (EPCOT Trial)

OBJECTIVE: Data from small studies have shown the presence of platelet abnormalities in patients with congestive heart failure (CHF). We sought to characterize the diagnostic utility of the whole blood aggregometry (WBA) in a random outpatient CHF population. METHODS: Blood samples were obtained for measurement of whole blood aggregation, shear-induced closure time, platelet contractile force, expression of GP IIb/IIIa, and P-selectin in 100 consecutive patients with CHF. RESULTS: Substantial inter-individual variability of platelet characteristics exists in patients with CHF. There were no statistically significant differences when patients were divided by the incidence of vascular events, emergency revascularization needs, survival, or etiology of heart failure. Surprisingly, aspirin use did not affect instrument readings as well. Whole blood aggregometry correlates well with the closure time (r(2)=0.587), and with GP IIb/IIIa expression (r(2)=0.435). Significant but less strong correlation has been observed for the WBA with platelet P-selectin expression (r(2)=0.295), and no correlation was present for the platelet contractile force measures (r(2)=0.030). CONCLUSIONS: Despite the fact that patients with heart failure enrolled in the EPCOT trial exhibited marginal, sometimes oppositely directed changes, in their platelet characteristics, whole blood impedance aggregometry is indeed capable to serve as a valuable diagnostic tool, and may be successfully used as an established screening device in this population. Ability of the whole blood aggregometry to predict clinical outcomes, or for the monitoring of anti-platelet agents in CHF patients, will be evaluated in the ongoing clinical trials.