In Vitro Comparative Study of Hemostatic Components in Warfarin-Treated and Fibrinogen-Deficient Plasma
Presented in part at the annual meeting of the American Society of Anesthesiologists, Orlando, FL, October 21, 2008, and at the annual meeting of the Society of Cardiovascular Anesthesiologists, San Antonio, TX, April 21, 2009.
published online 12 October 2009.
Objective
The authors hypothesized that various hemostatic products may differently affect viscoelastic clot formation depending on their respective procoagulant activity and fibrinogen content.
Design
In vitro coagulopathy modeling using warfarin-treated plasma (international normalized ratio, 2.8-3.8) and fibrinogen-deficient plasma evaluated by rotational thromboelastometry (ROTEM; Pentapharm, Munich, Germany).
Setting
A university laboratory.
Intervention
Different volumes of cryoprecipitate, fresh frozen plasma (FFP), fibrinogen concentrate, and platelet concentrate were mixed with each abnormal plasma to simulate the in vivo transfusions of 250 mL to 1,000 mL. Three thromboelastometric variables that reflect the rate and extent of clot growth were measured: (1) coagulation time (CT), (2) angle, and (3) maximal clot firmness (MCF).
Measurements and Main Results
In warfarin-treated plasma, the addition of FFP, cryoprecipitate, and platelets led to a dose-dependent improvement of CT and angle, whereas MCF increased with cryoprecipitate or platelets only. The addition of fibrinogen concentrate improved MCF and angle but not CT. In fibrinogen-deficient plasma, the addition of cryoprecipitate, platelets, and fibrinogen concentrate led to a dose-dependent improvement of ROTEM variables, whereas the addition of FFP resulted in significantly longer CT and lower MCF values compared with other hemostatic products. The addition of platelets in the presence of cytochalasin D (a platelet inhibitor) resulted in improvements of ROTEM variables that were similar to when FFP was added to warfarin-treated and fibrinogen-deficient plasma.
Conclusions
Cryoprecipitate supports clot formation on ROTEM more efficiently than FFP because of the high fibrinogen content. Improved ROTEM variables after platelet addition are presumably caused by increased interaction among thrombin-activated platelets and fibrinogen.
⁎Department of Anesthesiology, Emory University School of Medicine, Atlanta, GA
†Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA
Address reprint requests to Kenichi A. Tanaka, MD, MSc, Department of Anesthesiology, Emory University School of Medicine, 1364 Clifton Road NE, Atlanta, GA 30322
ABSTRACT