Hemodynamic Effects of A Simplified Venturi Conduit for Fontan Circulation: A Pilot, In Silico Analysis

Zhu, Fang; Shi, Guoyong; Wen, Chen; Zhang, Qian; Fu, Qihua; Liu, Jinlong; Zhu, Zhenan; Chen, Huiwen

doi:10.1038/s41598-020-57634-2

Cited by 9 publications

(11 citation statements)

References 29 publications

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“…Static pressure of 65 mm Hg was assigned at the inlet of the aortic graft to represent the mean arterial pressure. 69 Although the aortic pressure is strongly pulsatile, the device performance is strongly correlated with the time-averaged flow characteristics. The validity of using a time-aver- aged pressure for the aortic graft inlet was investigated.…”

Section: Boundary Conditionsmentioning

confidence: 99%

In Silico Evaluation of a Self-powered Venous Ejector Pump for Fontan Patients

Rasooli

Giljarhus

Hiorth

et al. 2023

Cardiovasc Eng Tech

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Purpose The Fontan circulation carries a dismal prognosis in the long term due to its peculiar physiology and lack of a subpulmonic ventricle. Although it is multifactorial, elevated IVC pressure is accepted to be the primary cause of Fontan's high mortality and morbidity. This study presents a self-powered venous ejector pump (VEP) that can be used to lower the high IVC venous pressure in single-ventricle patients. Methods A self-powered venous assist device that exploits the high-energy aortic flow to lower IVC pressure is designed. The proposed design is clinically feasible, simple in structure, and is powered intracorporeally. The device's performance in reducing IVC pressure is assessed by conducting comprehensive computational fluid dynamics simulations in idealized total cavopulmonary connections with different offsets. The device was finally applied to complex 3D reconstructed patient-specific TCPC models to validate its performance. Results The assist device provided a significant IVC pressure drop of more than 3.2 mm Hg in both idealized and patient-specific geometries, while maintaining a high systemic oxygen saturation of more than 90%. The simulations revealed no significant caval pressure rise (< 0.1 mm Hg) and sufficient systemic oxygen saturation (> 84%) in the event of device failure, demonstrating its fail-safe feature. Conclusions A self-powered venous assist with promising in silico performance in improving Fontan hemodynamics is proposed. Due to its passive nature, the device has the potential to provide palliation for the growing population of patients with failing Fontan.

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Section: Boundary Conditionsmentioning

confidence: 99%

In Silico Evaluation of a Self-powered Venous Ejector Pump for Fontan Patients

Rasooli

Giljarhus

Hiorth

et al. 2023

Cardiovasc Eng Tech

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“…Computational fluid dynamics (CFD) serves as a valuable tool to resolve the complex flows in the TCPC, and to understand the hemodynamics of the two types of connections [13][14][15][16][17][18][19][20][21]. CFD analysis allows for a more detailed analysis of flow structures (i.e., vortices, streamlines, pathlines, stagnation points, etc.…”

Section: Introductionmentioning

confidence: 99%

Fluid-Structure Interaction Simulation of an Intra-Atrial Fontan Connection

Tang

Wei

Fogel

et al. 2020

Biology

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Total cavopulmonary connection (TCPC) hemodynamics has been hypothesized to be associated with long-term complications in single ventricle heart defect patients. Rigid wall assumption has been commonly used when evaluating TCPC hemodynamics using computational fluid dynamics (CFD) simulation. Previous study has evaluated impact of wall compliance on extra-cardiac TCPC hemodynamics using fluid-structure interaction (FSI) simulation. However, the impact of ignoring wall compliance on the presumably more compliant intra-atrial TCPC hemodynamics is not fully understood. To narrow this knowledge gap, this study aims to investigate impact of wall compliance on an intra-atrial TCPC hemodynamics. A patient-specific model of an intra-atrial TCPC is simulated with an FSI model. Patient-specific 3D TCPC anatomies were reconstructed from transverse cardiovascular magnetic resonance images. Patient-specific vessel flow rate from phase-contrast magnetic resonance imaging (MRI) at the Fontan pathway and the superior vena cava under resting condition were prescribed at the inlets. From the FSI simulation, the degree of wall deformation was compared with in vivo wall deformation from phase-contrast MRI data as validation of the FSI model. Then, TCPC flow structure, power loss and hepatic flow distribution (HFD) were compared between rigid wall and FSI simulation. There were differences in instantaneous pressure drop, power loss and HFD between rigid wall and FSI simulations, but no difference in the time-averaged quantities. The findings of this study support the use of a rigid wall assumption on evaluation of time-averaged intra-atrial TCPC hemodynamic metric under resting breath-held condition.

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“…In contrast, the VEP demonstrates the advantage of being thoroughly evaluated for fail-safe features under various failure scenarios, ensuring the maintenance of high arterial oxygen saturation levels (> 80%) and low IVC pressure in cases of AoG occlusion. In another approach, a shunt from the ascending aorta to the anastomosis of the SVC and pulmonary arteries was suggested to lower venous pressure [42]. While computational simulations revealed its potential for providing a modest venous pressure drop (~ 1 mm Hg), the authors assumed a constant pressure at the pulmonary arteries, which does not accurately re ect the hemodynamic response due to signi cantly increased pulmonary ow.…”

Section: Discussionmentioning

confidence: 99%

In Vitro Hemodynamic Performance of a Blood Pump for Self-powered Venous Assist in Univentricular Hearts

Rasooli,

Holmstrom,

Giljarhus

et al. 2023

Preprint

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Univentricular heart anomalies represent a group of severe congenital heart defects necessitating early surgical intervention in infancy. The Fontan procedure, the final stage of single-ventricle palliation, establishes a serial connection between systemic and pulmonary circulation by channeling venous return to the lungs. The absence of the subpulmonary ventricle in this peculiar circulation progressively eventuates in failure, primarily due to chronic elevation in inferior vena cava (IVC) pressure. This study experimentally validates the effectiveness of an intracorporeally-powered venous ejector pump (VEP) in reducing IVC pressure in Fontan patients. The VEP exploits a fraction of aortic flow to create a jet-venturi effect for the IVC, negating the external power requirement and driveline infections. A multi-scale in-vitro Fontan mock-up circulation loop is developed and the impact of VEP design parameters and physiological conditions is assessed using both idealized and patient-specific total cavopulmonary connection (TCPC) phantoms. The VEP performance in reducing IVC pressure exhibited an inverse relationship with the cardiac output and extra-cardiac conduit (ECC) size and a proportional relationship with the transpulmonary pressure gradient (TPG) and mean arterial pressure (MAP). The ideal VEP with fail-safe features provided an IVC pressure drop of 1.82 ± 0.49, 2.45 ± 0.54, and 3.12 ± 0.43 mm Hg for TPG values of 6, 8, and 10 mm Hg, respectively, averaged over all ECC sizes and cardiac outputs. Furthermore, the arterial oxygen saturation was consistently maintained above 85% in all conditions. These results emphasize the potential utility of the VEP to mitigate elevated venous pressure in Fontan patients.

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Hemodynamic Effects of A Simplified Venturi Conduit for Fontan Circulation: A Pilot, In Silico Analysis

Cited by 9 publications

References 29 publications

In Silico Evaluation of a Self-powered Venous Ejector Pump for Fontan Patients

In Silico Evaluation of a Self-powered Venous Ejector Pump for Fontan Patients

Fluid-Structure Interaction Simulation of an Intra-Atrial Fontan Connection

In Vitro Hemodynamic Performance of a Blood Pump for Self-powered Venous Assist in Univentricular Hearts

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