Viscoelastic Hemostatic Testing as a Diagnostic Tool for Hypercoagulability in Liver Transplantation: A Narrative Review.

Liver transplantation is a complex surgical procedure in which various forms of coagulation dysfunction can occur, including perioperative hypercoagulability. The hemostasis balance in liver graft recipients with end-stage liver disease can shift to thrombosis or haemorrhage, depending on the associated risk factors and clinical conditions. Hypercoagulability can result in serious complications such as thromboembolism, which can affect the vessels of the newly transplanted liver graft. Standard coagulation tests (SCTs), such as prothrombin time and activated partial thromboplastin time (aPTT), have a poor ability to diagnose and monitor an early stage of hypercoagulability. Recent studies demonstrated that viscoelastic hemostatic elastic tests (VETs), such as rotational thromboelastometry (ROTEM) and thromboelastography (TEG), are promising alternative tools for diagnosing hypercoagulability disorders. VETs measure clotting and clot formation time, clot strength (maximum clot firmness), fibrin and platelet contribution to clot firmness, and fibrinolysis, which makes them more sensitive in identifying liver graft recipients at risk for thrombosis as compared with SCTs. However, developing evidence-based guidelines for the prophylaxis and treatment of hypercoagulability based on VET results is still needed.