Scaling the Low-Shear Pulsatile TORVAD for Pediatric Heart Failure.
This article provides an overview of the design challenges associated with scaling the low-shear pulsatile TORVAD ventricular assist device (VAD) for treating pediatric heart failure. A cardiovascular system model was used to determine that a 15 ml stroke volume device with a maximum flow rate of 4 L/min can provide full support to pediatric patients with body surface areas between 0.6 and 1.5 m. Low-shear stress in the blood is preserved as the device is scaled down and remains at least two orders of magnitude less than continuous flow VADs. A new magnetic linkage coupling the rotor and piston has been optimized using a finite element model (FEM) resulting in increased heat transfer to the blood while reducing the overall size of TORVAD. Motor FEM has also been used to reduce motor size and improve motor efficiency and heat transfer. FEM analysis predicts no more than 1°C temperature rise on any blood or tissue contacting surface of the device. The iterative computational approach established provides a methodology for developing a TORVAD platform technology with various device sizes for supporting the circulation of infants to adults.
From the *Windmill Cardiovascular Systems, Austin, Texas; †Division of Cardiovascular Medicine, University of Texas Medical School at Houston and The Memorial Hermann Heart and Vascular Institute, Houston, Texas; and ‡Department of Mechanical Engineering, University of Texas at Austin, Austin, Texas.
Jeffrey R
JR
Gohean
Erik R
ER
Larson
Brian H
BH
Hsi
Mark
M
Kurusz
Richard W
RW
Smalling
Raul G
RG
Longoria
D004867:Equipment Design; D020342:Finite Element Analysis; D006333:Heart Failure / Q000628:therapy*; D006353:Heart-Assist Devices; D006801:Humans; D007223:Infant; D008955:Models, Cardiovascular; D011673:Pulsatile Flow