Does the platelet function analyser (PFA-100®) predict blood loss after cardiopulmonary bypass?

Abstract

Background. This study was designed to determine if a new point-of-care test (PFA-100® platelet function analyser) that assesses platelet function predicts blood loss after cardiac surgery. Methods and results. Blood samples from 70 patients were drawn before and after cardiopulmonary bypass (CPB) for PFA-100® measurements. The system consists of a cartridge in which a membrane and an aperture are coated with either collagen/adenosine-5′-diphosphate or collagen/epinephrine. The instrument determines the time required for full occlusion of the aperture (closure time). We observed a weak correlation between pre-CPB collagen/epinephrine closure time and second-hour mediastinal blood loss (r=0.34, P=0.01). The sensitivity and positive predictive value of the PFA-100® measurements were comparable to platelet count for predicting excessive bleeding after CPB (75 and 27% vs 100 and 25%, respectively). Conclusions. The PFA-100® is a logical test for detecting patients who could have excessive bleeding after CPB. However, the PFA-100® was not able to separate patients at low risk of subsequent bleeding from those who had substantial bleeding.