Patient-Specific Multiscale Modeling of the Assisted Bidirectional Glenn

Area of Science:

• Cardiovascular Surgery
• Pediatric Cardiology
• Biomedical Engineering

Background:

• First-stage palliation for single-ventricle physiology presents significant clinical challenges and poor outcomes.
• The assisted bidirectional Glenn (ABG) procedure was proposed to improve pulmonary flow and oxygenation compared to the bidirectional Glenn (BDG).
• Previous studies using idealized models suggested ABG's potential benefits.

Purpose of the Study:

• To evaluate the performance of the assisted bidirectional Glenn (ABG) in patient-specific computational models.
• To assess the impact of varying shunt geometry on ABG hemodynamics.
• To compare ABG performance against the bidirectional Glenn (BDG) in simulated single-ventricle physiology.

Main Methods:

• Construction of 3D in silico models from a cohort of single-ventricle prestage 2 patients.
• Tuning of lumped parameter networks to match clinical measurements.
• Multiscale computational modeling coupling finite-element flow solver with lumped parameter networks to simulate hemodynamics under baseline and doubled pulmonary vascular resistance (PVR).
• Manipulation of shunt nozzle diameter, anastomosis location, and shape.

Main Results:

• The ABG procedure increased pulmonary flow rate and pressure by 15-20% across both low and high PVR conditions.
• Superior vena caval pressure increased by 2-3 mm Hg with ABG.
• Pulmonary flow and superior vena caval pressures demonstrated highest sensitivity to shunt nozzle diameter.

Conclusions:

• The assisted bidirectional Glenn (ABG) procedure demonstrated comparable performance in patient-specific models as in idealized ones.
• ABG showed good performance at lower pulmonary vascular resistance (PVR) values, aligning with clinical data.
• Larger shunt outlet diameters and lower PVR were identified as key factors for improved ABG efficacy.