Speaker

Ahmad Faryami, PhD candidate, Wayne State University

Abstract

INTRODUCTION: Despite 60 years of research and development, shunts are still the neurological devices with the highest failure rate: more than 50% of the shunts fail only after two years of implantation. Our recent analysis of astrocyte cytokine secretion under shear stress revealed a statistically significant increase in pro-inflammatory IL-6 cytokine secretion. Additionally, our patient MRI-driven CFD model has demonstrated that the elongated profile of commercial catheters creates a shear gradient, supporting our hypothesis that shunt obstruction is reduced in a catheter with optimized architecture. METHODS: Confocal microscopy was utilized to generate CAD models of unused and explanted catheters. CFD model was simulated using Ansys Fluent. Using a coupled pressure method, velocity and pressure profiles were extracted into Fluent Post Processing for imaging, to reveal localized high shear hotspots. A catheter with optimized architecture was designed and evaluated in-silico. RESULTS: The flow-optimized catheters demonstrated significantly more uniform distribution of flow through all the lateral holes in silico.  The CFD model also demonstrated a statistically significant reduction in maximum shear rate compared to standard catheters. Higher protein adsorption was observed in the proximity of the distal holes of catheters with the standard architecture compared to the flow-optimized catheter. CONCLUSIONS: A truly optimized catheter is the implementation of various modifications to current catheters. This is a brief description of catheter profile optimization.