Design Of A Cavopulmonary Assist Device Using Computational And Experimental Models
W.C. Patrick Lin1, Jonathan Adams1, Elyar Abbasi Bavil1, Gabrielle Sebaldt1, Matthew G. Doyle1, S Lucy Roche2, Thomas L. Forbes3, Cristina H. Amon4, osami Honjo5.
1Department of Mechanical and Industrial Engineering, University of Toronto, toronto, ON, Canada, 2Division of Medicine, University of Toronto, toronto, ON, Canada, 3Division of Vascular Surgery, Peter Munk Cardiac Centre & University of Toronto, toronto, ON, Canada, 4Institute of Biomaterials and Biomedical Engineering, University of Toronto, toronto, ON, Canada, 5Labatt Family Heart Centre, The Hospital for Sick Children, & Department of Surgery, University of Toronto, toronto, ON, Canada.
Objectives: To use computational and experimental methods to develop a cavopulmonary assist device as a bridge to transplantation for patients with failing Fontan circulation.
Methods: The proposed device is a double-lumen cannula inserted through the right jugular vein into the total cavopulmonary connection (TCPC) and coupled to an external centrifugal pump. Computational fluid dynamics were used to numerically simulate blood flow and to design a device which would increase the transpulmonary pressure gradient by 2-6 mmHg in idealized and patient-specific TCPC geometries. This should be sufficient to overcome clinically problematic pulmonary vascular resistance, improve cardiac output, and decompress end organs. Device performance was simulated for a range of physiological cardiac outputs. Two hemolysis indices were calculated to estimate red blood cell damage. Following device design, a 3-D printed prototype was manufactured for use in benchtop flow testing in a custom-built mock circulatory loop, designed to mimic the Fontan circulation.
Results: Pressure gains of up to 4-9 mmHg were achieved in the computational model for idealized and patient-specific TCPC geometries. Calculated hemolysis indices predict insignificant blood damage through the device with maximum values of 1.95 x 10-5. Benchtop experiments showed mean TCPC pressure reductions of approximately 1 mmHg with device assist at certain flow cases. Areas of concern in device design were also identified as part of the experiments.
Conclusion: A cavopulmonary assist device has been developed using computational and experimental methods. Initial simulations show promising results and further work is being done to refine the device design.
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