Venoarterial extracorporeal membrane oxygenation in adults with cardiogenic shock

Cardiogenic shock in adults continues to carry a high mortality despite advances in cardiac care, interventions and critical care. A major advancement in cardiogenic shock care came with the advent of temporary mechanical circulatory support including the intra-aortic balloon pump, ventricular assist devices, and venoarterial extracorporeal membrane oxygenation (VA ECMO). VA ECMO is a type of temporary mechanical circulatory support used in selected patients with cardiogenic shock that have failed to be adequately supported by less invasive approaches including vasoactive medications, volume optimization, and other temporary mechanical circulatory support. VA ECMO is resource intensive support strategy that requires expertise and cooperation from multiple specialties. Complications during VA ECMO support are common and include bleeding, acute kidney injury, stroke, mechanical complications during cannulation, hemolysis, and limb ischemia. VA ECMO circuits drain blood from the venous system, oxygenate and remove carbon dioxide, and return it to the arterial system, providing biventricular support. VA ECMO may be deployed peripherally (through femoral or internal jugular veins and returning blood to axillary or femoral arteries), or centrally from the right atrium to the aorta. Vascular access used for peripheral VA ECMO is large and includes arterial cannulas (usually 15 to 19 French), venous cannulas (usually 21 to 25 French), and a distal perfusion catheter (5 to 8 French). VA ECMO causes significant physiologic changes including reduced pulmonary blood flow, an inflammatory response, increases in left ventricular afterload, dual circulation when initiated through most peripheral sites, and coagulopathy. Management considerations for patients supported by VA ECMO are complex for multiple reasons including the differing approaches to the underlying cause of cardiogenic shock (for example, ischemic vs. non ischemic etiologies), patient comorbidities, whether the goal is recovery, heart transplant, or dischargeable ventricular assist device. Weaning from VA ECMO is a complex process with multiple possible approaches, and decannulation is most commonly accomplished through surgical or percutaneous approaches. There is a paucity of literature on VA ECMO and most guidance is based on retrospective data and expert opinion. What follows is an overview of VA ECMO for cardiogenic shock.