Scaling the Low-Shear Pulsatile TORVAD for Pediatric Heart Failure.

Area of Science:

• Biomedical Engineering
• Cardiovascular Device Design
• Pediatric Cardiology

Background:

• Pediatric heart failure requires specialized ventricular assist devices (VADs).
• Scaling existing VADs presents challenges in maintaining low-shear stress and efficiency.
• The TORVAD (transcutaneous outflow regulator VAD) is a pulsatile device with potential for pediatric application.

Purpose of the Study:

• To address the design challenges of scaling the low-shear pulsatile TORVAD for pediatric heart failure.
• To determine appropriate device parameters for full circulatory support in pediatric patients.
• To optimize the TORVAD's magnetic linkage and motor using computational modeling.

Main Methods:

• Utilized a cardiovascular system model to define device specifications (15 mL stroke volume, 4 L/min flow rate).
• Employed finite element modeling (FEM) to optimize magnetic linkage for heat transfer and size reduction.
• Applied motor FEM to enhance motor efficiency, reduce size, and improve heat transfer.

Main Results:

• A 15 mL stroke volume device supports pediatric patients (0.6-1.5 m² body surface area).
• Low-shear stress is maintained, significantly lower than continuous flow VADs.
• Optimized magnetic linkage and motor improve heat transfer and reduce device size, with predicted <1°C temperature rise on blood-contacting surfaces.

Conclusions:

• The developed TORVAD platform technology is scalable for infants to adults.
• The iterative computational approach provides a viable methodology for VAD development.
• Optimized TORVAD design offers efficient, low-shear circulatory support for pediatric and adult heart failure.