LAUSR

The field of percutaneous mechanical circulatory support (pMCS) and by extension of critical care has evolved markedly over recent years. In particular, the use of extracorporeal membrane oxygenation (ECMO) of balloon pumps and more recently microaxial-flow pumps has become more reliable with steadily improving technology and increasing experience, reflected in its improving results. Also, the possible duration of MCS support has greatly increased (from days to weeks) due to improved oxygenators and better medical management in dedicated high-volume ECMO centres [1]. Mechanical complications of pMCS have decreased with introduction of centrifugal pumps, low-resistance membranes and modern coating surfaces. Nevertheless, complications are still frequent and often jeopardize the patient’s outcome and survival. Critically ill pMCS patients often present with underlying renal and hepatic failure or sepsis, causing a pro-coagulant acute phase response [2]. Additionally, exposure of blood to the nonbiologic (negatively charged) artificial surfaces of pMCS circuits causes a complex activation of the coagulation system, next to platelet and leucocyte activation. This ultimately leads to a systemic inflammatory response syndrome with further disruption of the normal coagulation system. All these factors are contributory to both thrombosis (especially neurological complications and limb ischaemia) and bleeding. Not surprising, the reported rates of ECMO-associated venous thromboembolism (VTE) range from 18 to 85% [3]. Therefore, antithrombotic therapy is needed to maintain the patency of the extracorporeal circuit and reduce the risk of thrombosis and consumption coagulopathy. On the other hand, minimizing the risk of haemorrhage is crucial, as bleeding complications are not only devastating by themselves, but also necessitate prompt discontinuation of the anticoagulation therapy, further jeopardizing pMCS [4]. Up to 16% of venoarterial ECMO patients develop intracranial haemorrhage and nearly 60% of the ECMO population develops major bleeding. This can be associated with bad outcome, even if the patient survived the ECMO treatment [5]. Therefore, the precarious balance between bleeding and thrombotic complications forms a daily struggle for critical care physicians and strongly influences MCS-induced morbidity and mortality [6].