Ten years of our translational research in the field of veno-arterial extracorporeal membrane oxygenation

Abstract

Extracorporeal life support is a treatment modality that provides prolonged blood circulation, gas exchange and can substitute functions of heart and lungs to provide urgent cardio-respiratory stabilization in patients with severe but potentially reversible cardiopulmonary failure refractory to conventional therapy. Generally, the therapy targets blood pressure, volume status, and end-organs perfusion. As there are significant differences in hemodynamic efficacy among different percutaneous circulatory support systems, it should be carefully considered when selecting the most appropriate circulatory support for specific medical conditions in individual patients. Despite severe metabolic and hemodynamic deterioration during prolonged cardiac arrest, venoarterial extracorporeal membrane oxygenation (VA ECMO) can rapidly revert otherwise fatal prognosis, thus carrying a potential for improvement in survival rate, which can be even improved by introduction of mild therapeutic hypothermia. In order to allow a rapid transfer of knowledge to clinical medicine two porcine models were developed for studying efficiency of the VA ECMO in treatments of acute cardiogenic shock and progressive chronic heart failure. These models allowed also an intensive research of adverse events accompanying a clinical use of VA ECMO and their possible compensations. The results indicated that in order to weaken the negative effects of increased afterload on the left ventricular function the optimal VA ECMO flow in cardiogenic shock should be as low as possible to allow adequate tissue perfusion. The left ventricle can be also unloaded by an ECG-synchronized pulsatile flow if using a novel pulsatile ECMO system. Thus, pulsatility of VA ECMO flow may improve coronary perfusion even under conditions of high ECMO blood flows. And last but not least, also the percutaneous balloon atrial septostomy is a very perspective method how to passively decompress overloaded left heart.

Fig. 1

The percutaneous circulatory support systems: (a) Impella system, (b) TandemHeart system, (c) ECMO system.

Fig. 2

(A) Outline of the study protocol. VT– ventricular tachycardia, VF – ventricular fibrillation. (B) Comparison of effects of circulatory support systems on the mean arterial pressure (MAP) at ventricular fibrillation (VF): a – Impella system, b – TandemHeart system, c – ECMO system.

Fig. 3

(A) Outline of the study protocol. IABP – intraaortic balloon countepulsation, FF – femoro-femoral, FS – femoro-subclavian. (B) Carotid and coronary blood flow velocities relative to baseline. VF – ventricular fibrillation.

Fig. 4

(A) Outline of the study protocol. VF – ventricular fibrillation. (B) Effect of cardiac arrest and VA ECMO on selected parameters. TS O₂ – tissue oxygenation (%), MAP – mean arterial pressure (mm Hg), EGM – intracardiac electrograms amplitude (arb), K⁺ – plasma potassium (mmol/l), EGMs – intracardiac electrograms amplitude in successfully resuscitated animals, EGMn – intracardiac electrograms amplitude in non-successfully resuscitated animals.

Fig. 5

(A) Outline of the study protocol. VF – ventricular fibrillation. (B) Comparison of effects of mild hypothermia (HT) and normothermia (NT) on brain oxygen saturation and mean arterial pressure during the study protocol.

Fig. 6

Comparison of effects of mild hypothermia (HT) and normothermia (NT) on biomarkers of tissue injury at 90^th min of reperfusion.

Fig. 7

Comparison of hypoxic and ischemic model of the acute cardiogenic shock. SfvO₂ – blood oxygen saturation of femoral vein.

Fig. 8

Significant decreases in all hemodynamic parameters after development of heart failure in the ischemic model. BAS – baseline, HF – heart failure, CO – cardiac output, MAP – mean arterial pressure, LVEF – left ventricular ejection fraction, SvO2 – mixed venous blood saturation, CarFlow – flow in the right carotid artery, SV – stroke volume.

Fig. 9

Outline of the pacing protocol. HR – heart rate, AV – atrioventricular, D00 – operation mode, bpm – beats per minute.

Fig. 10

(A) Outline of the study protocol. (B) Comparison of effects of the venoatrial extracorporeal blood flow on selected hemodynamic parameters and parameters of the left ventricular performance.

Fig. 11

(A) Outline of the study protocol with representative example of EIT waveforms from one animal. Stepwise changes with increasing extracorporeal blood flow (EBF) are aligned with electrical impedance for both healthy (green) and heart failure (red) conditions. Electrical impedance waveforms represent impedance of lung regions during breathing cycles. (B) Comparison of effects of the venoatrial extracorporeal blood flow on selected hemodynamic parameters and EIT.

Fig. 12

(A) Outline of the study protocol. (B) Comparison of effects of continuous and pulsatile extracorporeal blood flow (EBF) on the coronary blood flow.

Fig. 13

(A) Outline of the study protocol. BAS – balloon atrial septostomy. (B) Comparison of effects of percutaneous balloon atrial septostomy (BAS) on stroke work, left ventricular end-diastolic volume (LVEDV) and left ventricular end-systolic pressure (LVESP).