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.