Assessing Platelet and Fibrinogen Contribution to Clot Strength Using Modified Thromboelastography in Pregnant Women

The monoclonal antibody fragment c7E3 Fab (ReoPro®), by binding to platelet surface fibrinogen receptors (glycoprotein, GPIIb/IIIa), inhibits platelet aggregation and its interaction with fibrinogen. In this study, we used thromboelastography with ReoPro® to evaluate the independent contribution of fibrinogen and platelets to clot strength. Thromboelastography was performed in 21 healthy, term parturients scheduled for elective cesarean delivery with 360 μL of celite-activated whole blood and with 5 μL of (2 mg/mL) ReoPro® added to 355 μL of celite-activated whole blood. The contribution of platelets to clot strength (MAplt) was derived by subtracting MAfib (maximal amplitude with ReoPro®) from MAwb (maximal amplitude with whole blood). Thus, MAwb -MAfib = MAplt. The value for MAwb (mean ± SD) was 73 ± 4 mm, for MAfib it was 33 ± 5 mm, and for MAplt it was 40 ± 3 mm. The contribution of fibrinogen and platelets to the MAplt was 45% and 55%, respectively. Modified thromboelastography using ReoPro® in healthy parturients can be used to determine the contribution of fibrinogen and platelets to blood clot strength. Implications: Determining the independent contribution of platelets and fibrinogen to the maximal amplitude of thromboelastography using c7E3 Fab may further improve the use of thromboelastography in detecting and treating coagulation defects.