Simulated Performance of a Bioprinted Pulsatile Fontan Conduit

Fontan physiology in single ventricle patients causes circulatory inefficiency, which contributes to various morbidities. To resolve these unfavorable hemodynamics, our interdisciplinary team is developing a 3D bioprinted conduit that could theoretically contract to provide a pulsatile energy source to the lungs. In this study, we evaluated design parameters of the pulsatile conduit by creating a 3D finite element simulation framework. We combined electromechanics with fluid-solid interaction in the 3D model and coupled it to a close-loop lumped-parameter network (LPN) of the Fontan circulation. This was implemented in the open-source software SimVascular. We used this framework to evaluate the effect of varying the conduit geometry, Purkinje network and fiber direction. The conduit was assumed to generate a 5 kPa active stress with 3 kPa passive stiffness based on previously estimated values of tissue-engineered materials. In a conduit with purely circumferential fiber alignment, we observed a 13. 61% volume amplitude while a 4 mmHg increment in conduit pressure. The central venous pressure of the Fontan circulation decreased from 15.5 to 14 mmHg. In a conduit with asymmetrically-oriented fibers, we observed a twisting motion as the dominant motion in the ventricle. This model generated a 9.3% ejection fraction and 2.5 mmHg pressure elevated. The central venous pressure could be able to decrease 1.4 mmHg. We concluded that the current performance of conduit is not sufficient to significantly improve Fontan physiology performance and recommend alternative target parameters that would yield desired outcomes.