Effects of Hemodilution on Clot Waveform Analysis Parameters, Clotting Factors, and Thrombin Generation Assays in a Dilutional Model Based on Analysis of 11 Healthy Male Blood Donors.

BACKGROUND Clot wave analysis (CWA) during activated partial thromboplastin time (aPTT) measures the speed and extent of fibrin polymerization in the plasma. This study aimed to evaluate the effects of hemodilution on CWA parameter, clotting factors, and thrombin generation assays in a dilutional model. MATERIAL AND METHODS Platelet-poor plasma obtained from 11 healthy male volunteers was diluted with 0.9% sodium chloride by 10-80% to analyze coagulation profiles, CWA, clotting factors, and thrombin generation assays. CWA includes 5 parameters: the time-dependent variable (aPTT), rate/acceleration (min1, min2, and max2), and magnitude of signal change (delta). RESULTS Critically low activities of 30% for clotting factors and 100 mg/dl of fibrinogen were determined at dilutions of 70% and 60%, respectively. Peak thrombin and endogenous thrombin potential were significantly lower compared with baseline after 50% and 80% dilution, respectively. aPTT did not correlate with the decrease in the clotting factors up to dilutions of 50% and subsequently became abnormal values. As the change in rate/acceleration parameters parallels the time course of clotting factor activity in a dilution-dependent linear manner, these parameters indicate an intervention threshold at critically low activities of clotting factors. The strongest correlations were observed between clotting factors and aPTT, clotting factors and min2, delta and peak thrombin (r=0.95), and delta and fibrinogen (r=0.98). CONCLUSIONS aPTT was significantly correlated with clotting factors, while the rate/acceleration parameters and delta changed with variation in thrombin and fibrinogen generation. These findings may help in evaluating coagulability.