EFFECT OF VENOARTERIAL EXTRACORPOREAL MEMBRANE OXYGENATION ON LEFT VENTRICULAR FUNCTION IN CARDIOGENIC SHOCK WITH AORTIC STENOSIS OR MITRAL REGURGITATION: AN EXPERIMENTAL STUDY IN PORCINE MODEL

Background: Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is widely used in the treatment of cardiogenic shock (CS). However, increased VA-ECMO blood flow (EBF) may significantly impair left ventricular (LV) performance. The objective of the present study was to assess the effect of VA-ECMO on LV function in acute CS with concomitant severe aortic stenosis (AS) or mitral regurgitation (MR) in a porcine model.
Methods: Eight female swine underwent VA-ECMO implantation and acute CS was induced by global myocardial hypoxia. Subsequently, severe AS was simulated by obstruction of the aortic valve, while severe MR was induced by mechanical destruction of the mitral valve. LV performance variables were measured at different rates of EBF rates (ranging from 1 to 4 L/min), using LV pressure-volume catheter. Data are expressed as median (interquartile range).
Results: In severe AS, increasing EBF from 1 to 4 L/min was associated with a significant elevation in mean arterial pressure (MAP), from 33.5 (24.2–34.9) to 56.0 (51.9–73.3) mmHg (P˂0.01). However, LV volumes (end-diastolic, end-systolic, stroke) remained unchanged, and LV end-diastolic pressure (LVEDP) significantly decreased from 24.9 (21.2–40.0) to 19.1 (15.2–29.0) mmHg (P˂0.01). In severe MR, increasing EBF resulted in a significant elevation in MAP from 49.0 (28.0–53.4) to 72.5 (51.4–77.1) mmHg (P˂0.01); LV volumes remained stable and LVEDP increased from 17.1 (13.7–19.1) to 20.8 (16.3–25.6) mmHg (P˂0.01).
Conclusion: Results of this study indicate that the presence of valvular heart disease may alleviate negative effect of VA-ECMO on LV performance in CS. Severe AS fully protected against LV overload, and partial protection was also detected with severe MR, although at the cost of increased LVEDP and, thus, higher risk for pulmonary oedema.