Discussion
In the past 10 years, the number of ECMO cases has increased, especially in the adult population (1). Undoubtedly, ECMO is a real revolution in the treatment of cardiac and respiratory failure, and its role is continuously evolving. ECMO as BTT is increasing (2).
Veno-arterial (VA) ECMO is used for cardiogenic shock from various causes that include acute myocardial infarction, myocarditis, acute decompensated heart failure, pulmonary embolism, post-cardiotomy cardiogenic shock, early or acute graft dysfunction, and refractory cardiac arrest. It can be used as a bridge to recovery, heart transplantation, or more durable mechanical circulatory support. There has been rapid growth of ECMO as a rescue therapy in the setting of acute cardiac failure, although the number of patients bridged to heart transplantation is small (3), it may increase with the implementation of changes to the adult heart allocation system (1,3).
Left ventricular distention can develop rapidly after peripheral VA-ECMO initiation, given the corresponding elevation in LV afterload which can lead to worsening LV end-diastolic volume and pressure. These condition changes can lead to reductions in transmural myocardial perfusion and impairs myocardial recovery and function. Resulting pulmonary hypertension and pulmonary edema diminishes the likelihood of ECMO weaning. In order to maximize the likelihood of cardiac recovery, some authors recommend LV decompression during VA-ECMO (4). The indication to vent the LV remains controversial. Generally, venting is utilized in cases of pulmonary edema, ventricular distension secondary to high afterload and inadequate venous drainage as well as with hearts without obvious ejection and a closed aortic valve or a significant aortic valve regurgitation (5).
Strategies to decompress the left ventricle include Impella, balloon atrial septostomy (with or without atrial stenting), a separate transseptal LA cannula (ie. Tandem Heart), transaortic cannula from the left subclavian, a cannula in the pulmonary artery and direct percutaneous apical LV venting (4). Furthermore, LA-VA ECMO has been described in which a single, multi-stage cannula is used to vent both atria (6). Dulnuan reported 3 patients using this technique with effective decompression of the LA with improvement of pulmonary edema (7).
To our knowledge, this is the first case in the literature to specifically describe the use of the NextGen cannula (Fig.1) for LA-VA ECMO. This cannula was originally designed for minimal invasive mitral surgery in which the conformation of the holes made it ideal for draining both atria. However, its design also makes it ideal for LA-VA ECMO. Inserted via a conventional transseptal approach, the first set of holes reside in the LA, while the second set terminate in the IVC (Fig. 2), allowing an effective venous drainage and left-side venting with just one cannula.