Veno-Arterial Extracorporeal Membrane Oxygenation for Cardiogenic Shock

Cardiogenic shock (CS) is a clinical condition characterized by inadequate tissue perfusion in the setting of low cardiac output. CS is the leading cause of death following acute myocardial infarction (AMI). Several temporary mechanical support devices are available for hemodynamic support in CS until clinical recovery ensues or until more definitive surgical procedures have been performed. Veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) has evolved as a powerful treatment option for short-term circulatory support in refractory CS. In the absence of randomized clinical trials, the utilization of ECMO has been guided by clinical experience and based on data from registries and observational studies. Survival to hospital discharge with the use of VA-ECMO ranges from 28-67%. The initiation of ECMO requires venous and arterial cannulation, which can be performed either percutaneously or by surgical cutdown. Components of an ECMO circuit include an inflow cannula that draws blood from the venous system, a pump, an oxygenator, and an outflow cannula that returns blood to the arterial system. Management considerations post ECMO initiation include systemic anticoagulation to prevent thrombosis, left ventricle unloading strategies to augment myocardial recovery, prevention of limb ischemia with a distal perfusion catheter in cases of femoral arterial cannulation, and prevention of other complications such as hemolysis, air embolism, and Harlequin syndrome. ECMO is contraindicated in patients with uncontrolled bleeding, unrepaired aortic dissection, severe aortic insufficiency, and in futile cases such as severe neurological injury or metastatic malignancies. A multi-disciplinary shock team approach is recommended while considering patients for ECMO. Ongoing studies will evaluate whether the addition of routine ECMO improves survival in AMI patients with CS who undergo revascularization.