The Hole of Hope: Balloon Atrial Septostomy for Left Ventricle Unloading during VA ECMO

Abstract

Veno arterial extracorporeal membrane oxygenation (VA-ECMO) is an established rescue therapy for cardiogenic shock (CS). However, the increase in left ventricle (LV) afterload associated with inappropriate LV unloading remains an unsolved problem. Balloon atrial septostomy (BAS) is an inexpensive effective with low complication rates. Our purpose was to understand BAS effect in this setting. Observational retrospective study, including patients submitted to BAS for LV unloading during VA-ECMO support due to CS between 2018 and 2019. Inotropic use was evaluated by the Wernovsky inotropic score. Statistical analysis was performed by median comparison with Wilcoxon test for related samples. Four patients with refractory CS despite VA-ECMO and intra aortic balloon pump (n=3) or Impella (n=1) support were included. The age of the patients was 55.5 years (IQR 46.8-64.3) and 75% were male. The basal median LV ejection fraction was 29.5%. All had severe functional mitral regurgitation and ischemic heart disease (n=3) or severe aortic stenosis (n=1). BAS was performed after a median time of 8 days (IQR 5.5-12.0) after ECMO with a final dimension of 5 mm. The reduction in left atrial pressure led to resolution of pulmonary edema in all patients. There was a hemodynamic improvement after the procedure, with lower inotropic use in 75% of patients (median difference -0,6; p= 1.00), and reduction in pulmonary pressures and lactate levels (Table 1). Additionally we documented an increase in LV outflow tract (LVOT) velocity time integral (VTI) and in the PaO2/FiO2 ratio. After a follow-up of 25.5 days (IQR 12.8-45.8) half of the patients were weaned from VA-ECMO or transplanted. One procedure was complicated by a femoral hematoma. Percutaneous BAS is a simple and effective procedure to treat refractory pulmonary edema during VA-ECMO support. The improvement in LV performance, documented by the increase in LVOT VTI, is likely due to improvement in intracavitary pressures and a better oxygenation.