Malposition of the Extracorporeal Membrane Oxygenation Venous Cannula in an Accessory Hepatic Vein

We report a case of a refractory cardiogenic shock secondary to myocardial infarction in a 70-year-old patient requiring femoral venoarterial extracorporeal membrane oxygenation (VA-ECMO). At initial transesophageal echocardiography, the venous cannula tip was seen in the inferior vena cava (IVC), but not in right atrium. On day 8, ultrasonic examination identified that the end of the venous cannula was in the hepatic vein (HV). Despite such malposition, no disturbance in extracorporeal membrane oxygenation (ECMO) venous return was observed. Moving or replacing the cannula was considered a high-risk maneuver potentially resulting in hepatic laceration with hemoperitoneum. Because of adequate venous drainage, allowing sufficient blood flow, venous cannula repositioning was delayed until day 10, when a ventricular defect was repaired and ECMO was weaned off. At the time of VA-ECMO implantation, the venous cannula has to be positioned in the right atrium using real time echo monitoring. Visualization of the guide wire in the IVC but not in the right atrium is insufficient to ensure appropriate venous cannula positioning. Indeed, either accidental catheterization or cannula migration into the HV is possible during ECMO. Health care professionals dealing with ECMO have to be aware of this possible malposition, to correct it and prevent insufficient venous drainage or traumatic complications.