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.