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 microL of celite-activated whole blood and with 5 microL of (2 mg/mL) ReoPro added to 355 microL 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.

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.