Hemi-ECMO: A Novel Method of Left Ventricular Afterload Reduction for Venoarterial Extracorporeal Membrane Oxygenation (VA-ECMO)

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) has failed to demonstrate mortality benefit in randomised controlled trials of cardiogenic shock. We aimed to determine whether a novel ‘Hemi-ECMO’ configuration, involving aortic occlusion to isolate the left ventricle from the VA-ECMO circuit, improves cardiac haemodynamics. We utilised a pulsatile biventricular mock circulatory loop with variable contractility to compare standard VA-ECMO with Hemi-ECMO support under left ventricular or biventricular failure conditions. When averaged across all pump speeds, mean left atrial pressure was significantly reduced with Hemi-ECMO compared to VA-ECMO (21.11 ± 1.32 mmHg vs. 26.53 ± 0.87 mmHg, p < 0.001), with more pronounced benefit at higher pump speeds. Aortic ejection increased with Hemi-ECMO at higher pump speeds: 0.14 ± 0.03 vs. 0.00 ± 0.00 L/min (p = 0.002) at 3000 revolutions per minute (RPM). Aortic ejection was greater with Hemi-ECMO in the descending aorta compared to the ascending aorta position (0.27 ± 0.03 L/min vs. 0.17 ± 0.05 L/min, p = 0.015). In conclusion, Hemi-ECMO demonstrates significant haemodynamic advantages in severe cardiogenic shock, including reductions in mean left atrial pressure and increases in aortic ejection, with greater benefits when positioned in the descending aorta. Further in vivo studies are warranted to assess clinical viability.