Jessica G Y Luc1, Clifford A Pierre2, Kevin Phan3, Yashar S Vahedein4, Alexander S Liberson4, William K Cornwell5, Steven J Phillips6, Vakhtang Tchantchaleishvili7. 1. Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB - Canada. 2. Department of Neurosurgery, University of Rochester Medical Center, Rochester, NY - USA. 3. Faculty of Medicine, University of Sydney, Sydney - Australia. 4. Kate Gleason College of Engineering, Rochester Institute of Technology, Rochester, NY - USA. 5. Division of Cardiology, Department of Internal Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO - USA. 6. National Library of Medicine, National Institutes of Health, U.S. Department of Health and Human Services, Bethesda, MD - USA. 7. Division of Cardiothoracic Surgery, Thomas Jefferson University, Philadelphia, PA - USA.
Abstract
PURPOSE: The current 1-dimensional fluid structure interaction model (FSI) for understanding cerebrospinal fluid (CSF) circulation requires pulsatility as a precondition and has not been applied to patients with continuous-flow left ventricular assist devices (CF-LVAD) where pulsatility is chronically reduced. Our study aims to characterize the behavior of CSF pressure and flow in patients with CF-LVADs using a computational FSI model. METHODS: Utilizing the computational FSI model, CSF production in choroid plexuses of the 4 ventricles was specified as a boundary condition for the model. The other source of production from capillary ultrafiltrate spaces was accounted for by the mass conservation equation. The primary CSF absorption sites (i.e., arachnoid granulations) were treated as the outlet boundary conditions. We established a low pulse wave to represent patients with a CF-LVAD. RESULTS: From the model, low pulse conditions resulted in a reduction in CSF pressure amplitude and velocity though the overall flow rate was unchanged. CONCLUSIONS: The existing FSI model is not a suitable representation of CSF flow in CF-LVAD patients. More studies are needed to elucidate the role of pulsatility in CSF flow and the compensatory changes in CSF production and absorption that occur in patients with CF-LVADs in whom pulsatility is diminished.
PURPOSE: The current 1-dimensional fluid structure interaction model (FSI) for understanding cerebrospinal fluid (CSF) circulation requires pulsatility as a precondition and has not been applied to patients with continuous-flow left ventricular assist devices (CF-LVAD) where pulsatility is chronically reduced. Our study aims to characterize the behavior of CSF pressure and flow in patients with CF-LVADs using a computational FSI model. METHODS: Utilizing the computational FSI model, CSF production in choroid plexuses of the 4 ventricles was specified as a boundary condition for the model. The other source of production from capillary ultrafiltrate spaces was accounted for by the mass conservation equation. The primary CSF absorption sites (i.e., arachnoid granulations) were treated as the outlet boundary conditions. We established a low pulse wave to represent patients with a CF-LVAD. RESULTS: From the model, low pulse conditions resulted in a reduction in CSF pressure amplitude and velocity though the overall flow rate was unchanged. CONCLUSIONS: The existing FSI model is not a suitable representation of CSF flow in CF-LVADpatients. More studies are needed to elucidate the role of pulsatility in CSF flow and the compensatory changes in CSF production and absorption that occur in patients with CF-LVADs in whom pulsatility is diminished.