Increasing venoarterial extracorporeal membrane oxygenation flow negatively affects left ventricular performance in a porcine model of cardiogenic shock

Abstract

Background: The aim of this study was to assess the relationship between extracorporeal blood flow (EBF) and left ventricular (LV) performance during venoarterial extracorporeal membrane oxygenation (VA ECMO) therapy.

Methods: Five swine (body weight 45 kg) underwent VA ECMO implantation under general anesthesia and artificial ventilation. Subsequently, acute cardiogenic shock with signs of tissue hypoxia was induced. Hemodynamic and cardiac performance parameters were then measured at different levels of EBF (ranging from 1 to 5 L/min) using arterial and venous catheters, a pulmonary artery catheter and a pressure-volume loop catheter introduced into the left ventricle.

Results: Myocardial hypoxia resulted in a decline in mean (±SEM) cardiac output to 2.8 ± 0.3 L/min and systolic blood pressure (SBP) to 60 ± 7 mmHg. With an increase in EBF from 1 to 5 L/min, SBP increased to 97 ± 8 mmHg (P < 0.001); however, increasing EBF from 1 to 5 L/min significantly negatively influences several cardiac performance parameters: cardiac output decreased form 2.8 ± 0.3 L/min to 1.86 ± 0.53 L/min (P < 0.001), LV end-systolic volume increased from 64 ± 11 mL to 83 ± 14 mL (P < 0.001), LV stroke volume decreased from 48 ± 9 mL to 40 ± 8 mL (P = 0.045), LV ejection fraction decreased from 43 ± 3 % to 32 ± 3 % (P < 0.001) and stroke work increased from 2096 ± 342 mmHg mL to 3031 ± 404 mmHg mL (P < 0.001). LV end-diastolic pressure and volume were not significantly affected.

Conclusions: The results of the present study indicate that higher levels of VA ECMO blood flow in cardiogenic shock may negatively affect LV function. Therefore, it appears that to mitigate negative effects on LV function, optimal VA ECMO blood flow should be set as low as possible to allow adequate tissue perfusion.

Fig. 1

Parameters measured from pressure–volume loop. EDP end-diastolic pressure, EDV end-diastolic volume, ESV end-systolic volume, SBP systolic blood pressure, SW stroke work

Fig. 2

Induction of regional myocardial hypoxia through perfusion of selected coronary artery by desaturated venous blood. LAD left anterior descending artery, LCx left circumflex artery, LM left main artery

Fig. 3

The effect of venoarterial extracorporeal membrane oxygenation blood flow on selected hemodynamic and left ventricular performance parameters in a porcine model of cardiogenic shock. EBF extracorporeal blood flow, EDP end-diastolic pressure, EDV end-diastolic volume, ESV end-systolic volume, HR heart rate, LVEF left ventricular ejection fraction, SBP systolic blood pressure, SV stroke volume, SW stroke work. *P < 0.05 compared with value at EBF 1 L/min