Effect of unfractionated heparin and low molecular weight heparin on the clotting of platelet-reduced whole blood: an in-vitro study utilizing thromboelastography.

Treatment of venous thromboembolism with concomitant thrombocytopenia is challenging. The platelet threshold for safe administration of anticoagulants is under debate, with minimum platelet count of 50 × 109/l being recommended as the safe cutoff. However, some evidence suggests administration of anticoagulants may still be safe at platelet levels of 30 × 109/l.

Rivaroxaban and dabigatran did not affect clotting profiles in plasma reconstituted with varying levels of autologous platelets to the same degree as heparin when evaluated using thromboelastography.

Objective: Current recommendations for treating patients with thromboembolism and concomitant thrombocytopenia are based on anecdotal data and expert opinion, rather than clinical studies. Our aim was to use an in-vitro model employing thromboelastography (TEG) to evaluate clot formation as a surrogate indicator of clinical tendency to hemorrhage, and investigate the interactions of plasma at varying concentrations of platelets in the presence of anticoagulants.

Methods: Platelet-rich and platelet-poor plasma isolated from whole blood were mixed together to obtain platelet concentrations ranging from less than 10-150 × 10 platelets/l.

In-vitro assessment of the effect of dabigatran on thrombosis of adult and neonatal plasma: comparisons using thromboelastography and microscopic visualization of fibrin clot structure.

: Thromboelastography (TEG) is a global assay used for evaluating features of clot formation in vitro. Dabigatran is a reversible direct inhibitor of thrombin that has not been studied in neonates using a sophisticated global assay, such as TEG. Neonatal hemostasis differs from adult hemostasis in both quantitative and qualitative characteristics.