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DESIGN OF A PHYSICAL WINDKESSEL MODEL FOR USE IN IN-VITRO BENCHTOP MODELING
Title
DESIGN OF A PHYSICAL WINDKESSEL MODEL FOR USE IN IN-VITRO BENCHTOP MODELING.
Creator
Beggs, Kyle, Kassab, Alain, University of Central Florida
Abstract / Description
Despite improved life expectancy compared to medical management alone, Ventricular Assist Device (VAD) recipients show survival rates of 80% at 12 months and 70% at 24 months. A large portion of VAD-associated mortality results from increased risk of stroke with an event frequency reported between 14-47%. Recent concerns have been raised about unprecedented increases of thrombus formation in VAD recipients with subsequent reports pointing towards implantation techniques as a critical...
Show moreDespite improved life expectancy compared to medical management alone, Ventricular Assist Device (VAD) recipients show survival rates of 80% at 12 months and 70% at 24 months. A large portion of VAD-associated mortality results from increased risk of stroke with an event frequency reported between 14-47%. Recent concerns have been raised about unprecedented increases of thrombus formation in VAD recipients with subsequent reports pointing towards implantation techniques as a critical contributor to these events. Thus, the overall prognosis with mechanical support can improve by advancing the surgeon's approach to VAD implantation. Previous studies using Computational Fluid Dynamics (CFD) were aimed at reducing stroke rates by tailoring the VAD outflow graft (VAD-OG) angle to direct any circulating emboli away from the cerebral vessels. In-vitro, or benchtop, models are often developed as computational counterparts. In order to accurately model the hemodynamics in the cardiovascular system, pulsatile flow must be mimicked. This is achieved in the computational domain by what is called a Windkessel model. This project seeks to develop a physical analogy to the Windkessel model for use in the benchtop experiments.
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Date Issued
2015
Identifier
CFH0004894, ucf:45420
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFH0004894
Investigation of a Self-powered Fontan Concept Using a Multiscale Computational Fluid-Structure Interaction Model
Title
Investigation of a Self-powered Fontan Concept Using a Multiscale Computational Fluid-Structure Interaction Model.
Creator
Beggs, Kyle, Kassab, Alain, Steward, Robert, Mansy, Hansen, DeCampli, William, University of Central Florida
Abstract / Description
Congenital Heart Disease (CHD) occurs in about 1\% (40,000) of newborn babies each year in the United States alone. About 10.9\% (960) of whom suffer from Hypoplastic Left Heart Syndrome (HLHS) - a subset of CHD where children are born with a single-ventricle (SV). A series of three surgeries are carried out to correct HLHS culminating in the Fontan procedure where venous flow returns passively to the lungs. The current configuration for the Fontan results in elevated Central Venous Pressure ...
Show moreCongenital Heart Disease (CHD) occurs in about 1\% (40,000) of newborn babies each year in the United States alone. About 10.9\% (960) of whom suffer from Hypoplastic Left Heart Syndrome (HLHS) - a subset of CHD where children are born with a single-ventricle (SV). A series of three surgeries are carried out to correct HLHS culminating in the Fontan procedure where venous flow returns passively to the lungs. The current configuration for the Fontan results in elevated Central Venous Pressure (CVP), inadequate ventricular preload, and elevated Pulmonary Vascular Resistance (PVR) leading to a barrage of disease. To alleviate these complications, a `self-powered' Fontan is suggested where an Injection Jet Shunt (IJS) emanating from the aorta is anastomosed to each pulmonary artery. The IJS attempts to reduce the central venous pressure, increase preload, and aid in pulmonary arterial growth by entraining the flow with a high energy source provided by the aorta. Previous computational studies on this concept with rigid vessel walls show mild success, but not enough to be clinically relevant. It is hypothesized that vessel wall deformation may play an important role in enhancing the jet effect to provide a larger exit area for the flow to diffuse while also being more physiologically accurate. A multiscale 0D-3D tightly coupled Computational Fluid Dynamics (CFD) with Fluid-Structure Interaction (FSI) model is developed to investigate the efficacy of the proposed `self-powered' Fontan modification. Several runs are made varying the PVR to investigate the sensitivity of IVC pressure on PVR. IVC pressure decreased by 2.41 mmHg while the rigid wall study decreased the IVC pressure by 2.88 mmHg. It is shown that IVC pressure is highly sensitive to changes in PVR and modifications to the Fontan procedure should target aiding pulmonary arterial growth as it is the main indicator of Fontan success.
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Date Issued
2018
Identifier
CFE0007311, ucf:52107
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0007311