[Blood Coagulation Disorders During ECMO and LVAD Therapy]

Extracorporal membrane oxygenation (ECMO) is used to stabilize severe cardiocirculatory and/or respiratory failure in emergency situations. Left ventricular assist devices (LVAD) are used for the treatment of severe chronic heart failure. ECMO and LVAD systems are increasingly employed and provide substantial benefit for respective patients. However, the use of ECMO and LVAD systems is associated with a multifactorial coagulopathy, which is characterized by thromboembolic and hemorrhagic complications. ECMO- and LVAD-induced thromboembolic events are caused by contact activation of plasmatic coagulation and platelets at the artificial surfaces of the respective system. Shear forces inside ECMO and LVADs further contribute to prothrombotic platelet activation. To prevent thrombotic occlusion of ECMO and LVAD systems anticoagulants are routinely administered. For this purpose heparin is primarily used. This may however result in heparin-induced thrombocytopenia, which can further complicate ECMO- and LVAD-associated coagulatory dysfunction. Bleeding complications during ECMO and LVAD therapy can be related to systemic anticoagulation. Qualitative and quantitative platelet defects as well as shear force induced acquired von Willebrand disease further contribute to hemorrhagic events. In conclusion, the management of the ECMO- and LVAD-associated coagulopathy is based on the understanding of its contributing factors. Respective causes for thrombotic and/or hemorrhagic complications should be identified with coagulation assays including viscoelastic point of care tests and platelet aggregometry. Once the underlying reason for the observed coagulopathy has been identified further treatment measures should be individually tailored.