Left ventricular unloading during veno-arterial ECMO: a review of percutaneous and surgical unloading interventions

Abstract

Short-term mechanical support by veno-arterial extracorporeal membrane oxygenation (VA ECMO) is more and more applied in patients with severe cardiogenic shock. A major shortcoming of VA ECMO is its variable, but inherent increase of left ventricular (LV) mechanical load, which may aggravate pulmonary edema and hamper cardiac recovery. In order to mitigate these negative sequelae of VA ECMO, different adjunct LV unloading interventions have gained a broad interest in recent years. Here, we review the whole spectrum of percutaneous and surgical techniques combined with VA ECMO reported to date.

Keywords: cardiogenic shock; cardiovascular modeling; computer simulation; left ventricular unloading; veno-arterial extracorporeal membrane oxygenation (VA ECMO).

Figure 1.

a. LV pressure-volume loops in normal physiology (red), severe systolic left heart failure (dark red) and when systemic circulation is supported by VA ECMO 4 L/min (black). Right shift of the loop indicates dilatation, which is worsened with VA ECMO, mainly due to an increase in afterload. b. LV pressure-volume loops in severe left heart failure supported by VA ECMO 4 L/min (black) in conjunction with different support modalities aimed at LV unloading. Intra-aortic balloon pumping (blue) results in increasing stroke volumes, with a modest unloading effect, while LV venting into the ECMO system (dark red) achieves better unloading. Atrial septostomy (red) achieves efficient LV unloading, but results in smaller stroke volumes, while the most effective unloading is seen with the Impella^® (green). For further details, see main text.