Visualizing Flow Dynamics in a Human Aorta During Peripheral Veno-Arterial Extracorporeal Membrane Oxygenation Treatment Through Particle Image Velocimetry Study.

Abstract

Purpose: To build a mock circulatory loop to simulate veno-arterial extracorporeal membrane oxygenation (V-A ECMO) haemodynamics using a patient-specific silicone aortic phantom and compare the flow dynamics for continuous and pulsatile ECMO settings.

Methods: A silicone model of a human aorta with major branches was fabricated and the left iliac artery was cannulated using a Xenios ECMO device to simulate a peripheral V-A ECMO configuration. The left ventricular outflows at the aortic root were simulated using a piston pump. Particle image velocimetry (PIV) experiments were conducted to measure flow velocities along the aortic phantom for a severe heart failure condition (LV = 1 L/min) supported by ECMO (4 L/min) at a heart rate of 80 bpm.

Results: Comparing all ECMO support modes, counter pulse ECMO mode exhibited higher velocities during both peak systolic and mid-diastolic phases. This shows that the LV and ECMO device supplied fluid into the aorta with less flow resistance, whereas other modes exhibited higher flow resistance due to the flow collision of antegrade LV and retrograde ECMO flow in the aorta.

Conclusion: Pulsatile flow ECMO with better placement of ECMO pulse delivery in the cardiac cycle could develop greater pulsatility into the aorta, which is crucial for transferring haemodynamic energy and reducing cardiac afterload.