Simulation of Fluid-Structure Interaction in Extracorporeal Membrane Oxygenation Circulatory Support Systems

Abstract

Extracorporeal membrane oxygenation (ECMO) is a vital mechanical circulatory support modality capable of restoring perfusion for the patient in circulatory failure.Despite increasing adoption of ECMO there is incomplete understanding of its effects on systemic hemodynamics and how the vasculature responds to varying levels of continuous retrograde perfusion. To gain further insight into the complex ECMO:failingheart circulation, computational fluid dynamics simulations focused on perfusion distribution and hemodynamic flow patterns were conducted using a patient-derived aorta geometry. Three case scenarios were simulated: (1) healthy control; (2) 90% ECMO-derived perfusion to model profound heart failure; and, (3) 50% ECMO-derived perfusion to model the recovering heart. Fluid-structure interface simulations were performed to quantify systemic pressure and vascular deformation throughout the aorta over the cardiac cycle. ECMO support alters pressure distribution while decreasing shear stress. Insights derived from computational modeling may lead to better understanding of ECMO support and improved patient outcomes.

Patient-Specific Computational Modeling of Different Cannulation Strategies for Extracorporeal Membrane Oxygenation

“…33 As reported by Seethararam and colleagues, complex flow features, including unsteady swirling, vortical flows, are encountered through the aorta due to the interaction between pulsatile cardiac flow and steady-state ECMO. 18 In our current study we found that the location of disturbed flow, and high wall shear stress co-localized with the insertion site of the arterial cannula, confirming previous findings by Nezami et al 22 The peak oscillatory shear was located around the arterial cannula in the AAC and SAC model, most likely due to local recirculation of flow. The peak OSI for the FAC model was located in close proximity to the flow mixing zone the aortic arch.…”

“…16,17 More specifically, CFD analyses have been used to provide a mechanistic interpretation of ECMO, including the impact of varying flow rates on differential hypoxemia, flow mixing phenomena, and neurological complications related to ECMO. [18][19][20][21][22] In this work on adult ECMO, we evaluated global and regional hemodynamics in a 56-year-old patient on peripheral VA-ECMO following acute cardiopulmonary failure using a patient-specific CFD analysis, where we explored the hemodynamic alterations introduced by different ECMO configurations, and identified contributions of pulsatile cardiac and nonpulsatile ECMO flows to various endorgan vascular beds.…”

The effect of arterial cannula tip position on differential hypoxemia during venoarterial extracorporeal membrane oxygenation

“…Various studies have previously investigated mixing zone location during VA ECMO using a CFD model [7][8][9][10][11]. However, these studies primarily involved variation of VA ECMO ow rates with a constant cannula position throughout.…”

“…Incorporating wall deformability would require much higher computational power than was feasible for the number of simulations conducted. However, Nezami et al included wall deformability and their mixing zone results showed negligible difference to simulations conducted with rigid vessel walls [9]. Secondly, the resistance and compliance parameters used in the Windkessel model re ect healthy patient conditions.…”

“…CFD enables researchers to investigate the effect of different cannula positions on pressure and ow elds, including mixing zones, with spatial and temporal resolution unattainable by clinical methods. Previous studies have used CFD to investigate the effect of increasing cannula ow rate on mitigating differential hypoxemia [7][8][9][10][11].…”