Calibration of an Electrical Analog Model of Liver Hemodynamics in Fontan Patients

Elyar Abbasi Bavil; Matthew G Doyle; Charlotte Debbaut; Rachel M Wald; Luc Mertens; Thomas L Forbes; Cristina H Amon

doi:10.1115/1.4049075

Calibration of an Electrical Analog Model of Liver Hemodynamics in Fontan Patients

J Biomech Eng. 2021 Mar 1;143(3):031011. doi: 10.1115/1.4049075.

Authors

Elyar Abbasi Bavil¹, Matthew G Doyle², Charlotte Debbaut³, Rachel M Wald⁴, Luc Mertens⁵, Thomas L Forbes⁶, Cristina H Amon⁷

Affiliations

¹ Department of Mechanical and Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, ON M5S 3G8, Canada.
² Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON M5S 3E2, Canada; Division of Vascular Surgery, Peter Munk Cardiac Centre, University Health Network, University of Toronto, 200 Elizabeth Street, Eaton North 6-222, Toronto, ON M5G 2C4, Canada.
³ IBiTech-bioMMeda, Department of Electronics and Information Systems, Ghent University, Campus UZ-Blok B-entrance 36, Corneel Heymanslaan 10, Ghent 9000, Belgium.
⁴ Peter Munk Cardiac Centre,Division of Cardiology, University Health Network, University of Toronto, 5N-517, 585 University Avenue, Toronto, ON M5G 2N2, Canada.
⁵ The Labatt Family Heart Centre,Division of Cardiology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, 555 University Avenue, Toronto, ON M5G 1X8, Canada; Peter Munk Cardiac Centre, Division of Cardiology, University Health Network, University of Toronto, 5N-517, 585 University Avenue, Toronto, ON M5G 2N2, Canada.
⁶ Division of Vascular Surgery, Peter Munk Cardiac Centre, University Health Network, University of Toronto, 200 Elizabeth Street, Eaton North 6-222, Toronto, ON M5G 2N2, Canada.
⁷ Department of Mechanical and Industrial Engineering, Institute of Biomedical Engineering, University of Toronto, 5 King's College Road, Toronto, ON M5S 3G8, Canada.

PMID: 33170219
DOI: 10.1115/1.4049075

Abstract

Fontan associated liver disease is a common complication in patients with Fontan circulation, who were born with a single functioning heart ventricle. The hepatic venous pressure gradient (HVPG) is used to assess liver health and is a surrogate measure of the pressure gradient across the entire liver (portal pressure gradient (PPG)). However, it is thought to be inaccurate in Fontan patients. The main objectives of this study were (1) to apply an existing detailed lumped parameter model (LPM) of the liver to Fontan patients using patient-specific clinical data and (2) to determine whether HVPG is a suitable measurement of PPGs in these patients. An existing LPM of the liver blood circulation was applied and tuned to simulate patient-specific liver hemodynamics. Geometries were collected from seven adult Fontan patients and used to evaluate model parameters. The model was solved and tuned using waveform measurements of flows, inlet and outlet pressures. The predicted ratio of portal to hepatic venous pressures is comparable to in vivo measurements. The results confirmed that HVPG is not suitable for Fontan patients, as it would underestimate the portal pressures gradient by a factor of 3 to 4. Our patient-specific liver model provides an estimate of the pressure drop across the liver, which differs from the clinically used metric HVPG. This work represents a first step toward models suitable to assess liver health in Fontan patients and improve its long-term management.

Keywords: Fontan procedure; biological system modeling; electrical analog model; fluid dynamics; liver hemodynamics.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Portal Pressure*