Optimization of inflow waveform phase-difference for minimized total cavopulmonary power loss

Area of Science:

• Biomedical Engineering
• Cardiovascular Physiology
• Computational Fluid Dynamics

Background:

• The Fontan operation is a palliative surgery for single ventricle congenital heart defects.
• Total cavo-pulmonary connection (TCPC) reroutes superior vena cava (SVC) and inferior vena cava (IVC) to pulmonary arteries (PA).
• Optimized hemodynamics and minimized power loss are crucial for Fontan procedure success.

Purpose of the Study:

• To investigate how temporal variations in SVC and IVC flow waveforms affect power loss in TCPC.
• To characterize power loss changes due to phase-shift and amplitude variations between SVC and IVC flows.
• To analyze the impact of respiration and pulsatility on energy dissipation within the TCPC pathway.

Main Methods:

• Utilized an experimentally validated pulsatile computational fluid dynamics (CFD) solver.
• Quantified energy dissipation by analyzing unsteady hemodynamics in idealized TCPC geometries.
• Incorporated patient-specific real-time phase-contrast magnetic resonance imaging (PC-MRI) flow waveforms from Fontan patients.

Main Results:

• Optimizing the phase-shift between caval flows reduced energy dissipation by up to 30% in idealized models.
• For patient-specific waveforms, power loss decreased by up to 11% through harmonic optimization at a mean flow of 3 L/min.
• Hemodynamic efficiency of single ventricle circuits is significantly influenced by caval flow waveform quality.

Conclusions:

• Caval flow waveform quality, regulated by respiratory pathways, strongly impacts single ventricle circuit efficiency.
• Patient-specific waveform optimization may offer therapeutic strategies to improve postoperative hemodynamics in Fontan patients.
• Findings suggest potential for enhancing Fontan patient outcomes through hemodynamic optimization.