P15: Durable Continuous-Flow Ventricular Assist Device For Biventricular Circulatory Support

Abstract

Objective: The biventricular assist device (BVAD, Fig. 1A) implantation is indicated for severe biventricular heart failure (BHF). We are developing an innovative, automatic, universal ventricular assist device (UVAD, Fig. 1B, 1C, and 1D), intended for biventricular or for single ventricular support (RVAD or LVAD). Pump rotor can move axially to regulate the impeller discharge aperture size, depending on the pressure difference between the inflow and outflow and pump speed. Herein, we report on UVAD research progress. Methods: The hardware used during RVAD/LVAD studies, consisted of a microcontroller development board (NXP FRDM-KV31F) in conjunction with a 3-phase BLDC motor driver board (NXP FRDM-MC-LVPMSM). Two UVAD pumps incorporated into the biventricular circulatory mock loop were used (Abbott Laboratories PVAD™, Abbott Park, IL, USA) to simulate BHF. Each interchangeable cannula has been designed as a four-piece assembly with a threaded connection and face seal with the inflow port of the UVAD (Fig. 1E). Computational flow dynamics (CFD) model (Fig. 1F) enabled automatic re-meshing of the internal fluid volume with vertical repositioning of the rotor and resulting changes in aperture size (ANSYS [Canonsburg, PA, USA] software, including DesignModeler, ANSYS-Meshing, CFX, and CFD-Post). Results: The hemodynamic requirements were met with both RVAD and LVAD settings. Flow pattern, shear stress, and residence times were similar at RVAD and LVAD nominal conditions. Interchangeable inflow cannulas allowed customization of cannulation strategies in RVAD and LVAD conditions, showing stable hemodynamic support with single or dual-device configurations. Conclusion: The UVAD architecture for single or dual-device configurations has been demonstrated in simulated BHF conditions. Device features such as incorporated pressure regulator and interchangeable inflow cannula enable patient centered customization of device use.Figure 1. A - BVAD setup; B - UVAD; C - Device aperture design; D - Cross section; E – Interchangeable inflow cannulas; F – Impeller regions and CFD contour plot.