DISCUSSION
VA-ECMO can serve as a bridge to cardiac transplantation in patients with cardiogenic shock. In peripheral VA-ECMO the arterial cannula provides retrograde flow toward the aortic valve which increases the afterload. Blood continues to fill the LV through normal myocardial blood drainage (Thebesian veins), any systemic venous return that flows past the ECMO cannula without being entrained, and in some patients through AI3. When this LV volume cannot be fully ejected against the increased afterload it leads to progressive LV distention, increased wall stress, and ultimately myocardial oxygen utilization. In patients with an incompetent mitral valve (as in our case), this pressure is transmitted into the LA leading to increases in LA pressure and potentially precipitating the development or worsening of cardiogenic pulmonary edema. LV distention in patients on VA-ECMO is associated with impaired myocardial recovery4 and LV decompression appears to decrease mortality and improve the likelihood of successful eventual weaning5,6. For these reasons, multiple LV venting strategies have been developed, though there are no guidelines regarding patient selection for and timing of LV venting in VA ECMO. In our patient this decision was driven by the presence of several factors recognized as indications for LV venting including; severe, persistent LV dysfunction, markedly dilated left ventricular chamber with elevated pressures refractory to optimal medical therapy, and a concern that the observed AI severity could substantially worsen with the increased afterload of peripheral VA-ECMO7. Recently, bi-atrial drainage through a single venous cannula for LAVA-ECMO has been described1,2. The decision to place a single venous cannula for LAVA-ECMO was based upon a desire to avoid placement of an additional femoral cannula that would have further interfered with patient ambulation, and avoidance of the need to incorporate an additional drainage cannula into the ECMO circuit with the need for additional tubing, a flow probe, and a flow-regulating clamp. We describe the first report of 3D TEE to guide placement of a single LAVA-ECMO venous cannula. In our case, 3D TEE including live 3D imaging along with “online” measurements obtained at the time of positioning utilizing 3D multiplanar reconstruction were particularly useful. Furthermore, offline demonstration of workflow used to align three planes for cannula measurement are presented.