Mechanical Left Ventricular Unloading in Patients Undergoing Venoarterial Extracorporeal Membrane Oxygenation

Abstract

Background: Venoarterial extracorporeal membrane oxygenation (VA-ECMO) increases left ventricular (LV) afterload, potentially provoking LV distention and impairing recovery. LV mechanical unloading (MU) with intra-aortic balloon pump (IABP) or percutaneous ventricular assist device (pVAD) can prevent LV distension, potentially at the risk of more complications, and net clinical benefit remains uncertain.

Objectives: This study aims to determine the association between MU and outcomes for patients undergoing VA-ECMO.

Methods: The authors queried the Extracorporeal Life Support Organization registry for adults receiving peripheral VA-ECMO from 2010 to 2019 and stratified them by MU with IABP or pVAD. The primary outcome was in-hospital mortality; secondary outcomes included on-support mortality and complications during VA-ECMO.

Results: Among 12,734 VA-ECMO patients, 3,399 (26.7%) received MU: 2,782 (82.9%) IABP and 580 (17.1%) pVAD. MU patients were older (age 56.3 vs 52.7 years) and, before extracorporeal membrane oxygenation, more often required >2 vasopressors (41.7% vs 27.2%) and had respiratory (21.1% vs 15.9%), renal (24.6% vs 15.8%), and liver failure (4.4% vs 3.1%) (all P < 0.001). MU patients had lower in-hospital mortality (56.6% vs 59.3%, P = 0.006), which persisted in multivariable modeling (adjusted OR [aOR]: 0.84; 95% CI: 0.77-0.92; P < 0.001). MU was associated with more cannula site bleeding (aOR: 1.25; 95% CI: 1.11-1.40; P < 0.001) and hemolysis (aOR: 1.27; 95% CI: 1.03-1.57; P = 0.02). Compared to pVAD, MU patients with IABP had similar mortality (aOR: 0.80; 95% CI: 0.64-1.01; P = 0.06) and less medical bleeding (aOR: 0.45; 95% CI: 0.31-0.64; P < 0.001), cannula site bleeding (aOR: 0.72; 95% CI: 0.54-0.96; P = 0.03), and renal injury (aOR: 0.78; 95% CI: 0.62-0.98; P = 0.03).

Conclusions: Among adults receiving VA-ECMO, MU was associated with lower in-hospital mortality despite increased complications including hemolysis and cannulation site bleeding. Compared to pVAD, MU with IABP was associated with similar mortality and lower complication rates.

Keywords: intra-aortic balloon pump; percutaneous ventricular assist device; survival; unloading; venoarterial extracorporeal membrane oxygenation.

Conflict of interest statement

Funding Support and Author Disclosures Dr Tonna has received a Career Development Award from the National Institutes of Health/National Heart, Lung, And Blood Institute (K23 HL141596); has received speaker fees and travel compensation from LivaNova, unrelated to this work; and is the Chair of the ELSO Registry Scientific Oversight Committee. Dr Kapur has received institutional research support and speaker/consulting honoraria from Abbott, Abiomed, Boston Scientific, Getinge, LivaNova, Medtronic, MDStart, Precardia, and Zoll. Dr Shaefi has received grants from the National Institutes of Health (K08 GM134220-01 and R01 DK125786-01). Dr Garan has received research support from Abbott Vascular and Verantos; and has received consultant fees from Abiomed and NupulseCV. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.

Copyright © 2022 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Figures

FIGURE 1. Flow Diagram of Patient Selection

Flow chart of patient selection for the analytic cohort. IABP = intra-aortic balloon pump; LV = left ventricle; pVAD = percutaneous ventricular assist device; VA-ECMO = venoarterial extracorporeal membrane oxygenation.

FIGURE 2. Left Ventricular Mechanical Unloading and In-Hospital Mortality Across Subgroups

Forest plot of the OR (95% CI) from multivariable logistic regression modeling examining the interaction of key clinical subgroups on the association of left ventricular mechanical unloading and in-hospital mortality in VA-ECMO patients. CHF = congestive heart failure; ECMO = extracorporeal membrane oxygenation; ECPR = extracorporeal cardiopulmonary resuscitation; VA-ECMO = venoarterial extracorporeal membrane oxygenation; VT/VF = ventricular tachycardia/ventricular fibrillation.

FIGURE 3. VA-ECMO Outcomes With IABP vs pVAD for Left Ventricular Mechanical Unloading

Forest plot of the OR (95% CI) from multivariable logistic regression modeling examining the association of left ventricular mechanical unloading with IABP versus pVAD and outcomes in VA-ECMO patients. IABP = intra-aortic balloon pump; pVAD = percutaneous ventricular assist device; other abbreviation as in Figure 2.

CENTRAL ILLUSTRATION. Left Ventricular Mechanical Unloading during Venoarterial Extracorporeal Membrane Oxygenation: Temporal Trends and Association With Outcomes

(A) Rates of left ventricular mechanical unloading with intra-aortic balloon pump (IABP) or percutaneous ventricular assist device (pVAD) in patients undergoing venoarterial extracorporeal membrane oxygenation (VA-ECMO) from 2010 to 2019. (B) Forest plot of the OR (95% CI) from multivariable logistic regression modeling examining the association of left ventricular mechanical unloading and outcomes in VA-ECMO patients.