216: Arterial Cannula Size and the Need for Delayed Left Ventricular Mechanical Unloading in Adults Supported with VA-ECMO: An ELSO Registry Analysis

Introduction: VA-ECMO is commonly used with left ventricular mechanical unloading (LVMU), including intra-aortic balloon pump (IABP) or percutaneous left ventricular assist device (pVAD). The impact of arterial cannula size on the need for a delayed LVMU is unknown. Methods: We queried the ELSO Registry from 2017-2022 for adults undergoing VA-ECMO and stratified them by small (<16 Fr) versus large (≥16 Fr) arterial cannula. We excluded those with concomitant LVMU, central cannulation and multiple runs. The primary outcome was the need for delayed LVMU, defined as IABP or pVAD placed >3 hours after ECMO initiation, and the influence of arterial cannula size was examined using multivariate logistic regression modeling. Results: Among 6216 adults supported with VA-ECMO who met study criteria, 1230 (19.8%) patients received a small arterial cannula (SAC). Patients with a SAC were less likely to be male, had smaller BSA, a lower incidence of pre-ECMO arrest, a lower incidence of pre-ECMO organ failures, and were less likely to be on >2 vasopressors (Table 1). Among 341 (5.5%) patients who underwent delayed LVMU, those with a small arterial cannula were more likely to receive IABP whereas patients with larger arterial cannula were more likely to receive a pVAD (Figure A). In multivariable modeling, the use of a small arterial cannula was not associated with the need for a delayed LVMU device (Figure B). Conclusions: In adults supported with VA-ECMO, there was no difference in the need for a delayed LVMU device among patients receiving a small versus larger arterial cannula.