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Govindarajan V, Marshall L, Sahni A, Cetatoiu MA, Eickhoff EE, Davee J, St Clair N, Schulz NE, Hoganson DM, Hammer PE, Ghelani SJ, Prakash A, Del Nido PJ, Rathod RH. Impact of Age-Related Change in Caval Flow Ratio on Hepatic Flow Distribution in the Fontan Circulation. Circ Cardiovasc Imaging 2024; 17:e016104. [PMID: 38567518 PMCID: PMC11073583 DOI: 10.1161/circimaging.123.016104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 03/15/2024] [Indexed: 04/04/2024]
Abstract
BACKGROUND The Fontan operation is a palliative technique for patients born with single ventricle heart disease. The superior vena cava (SVC), inferior vena cava (IVC), and hepatic veins are connected to the pulmonary arteries in a total cavopulmonary connection by an extracardiac conduit or a lateral tunnel connection. A balanced hepatic flow distribution (HFD) to both lungs is essential to prevent pulmonary arteriovenous malformations and cyanosis. HFD is highly dependent on the local hemodynamics. The effect of age-related changes in caval inflows on HFD was evaluated using cardiac magnetic resonance data and patient-specific computational fluid dynamics modeling. METHODS SVC and IVC flow from 414 patients with Fontan were collected to establish a relationship between SVC:IVC flow ratio and age. Computational fluid dynamics modeling was performed in 60 (30 extracardiac and 30 lateral tunnel) patient models to quantify the HFD that corresponded to patient ages of 3, 8, and 15 years, respectively. RESULTS SVC:IVC flow ratio inverted at ≈8 years of age, indicating a clear shift to lower body flow predominance. Our data showed that variation of HFD in response to age-related changes in caval inflows (SVC:IVC, 2, 1, and 0.5 corresponded to ages, 3, 8, and 15+, respectively) was not significant for extracardiac but statistically significant for lateral tunnel cohorts. For all 3 caval inflow ratios, a positive correlation existed between the IVC flow distribution to both the lungs and the HFD. However, as the SVC:IVC ratio changed from 2 to 0.5 (age, 3-15+) years, the correlation's strength decreased from 0.87 to 0.64, due to potential flow perturbation as IVC flow momentum increased. CONCLUSIONS Our analysis provided quantitative insights into the impact of the changing caval inflows on Fontan's long-term HFD, highlighting the importance of SVC:IVC variations over time on Fontan's long-term hemodynamics. These findings broaden our understanding of Fontan hemodynamics and patient outcomes.
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Affiliation(s)
- Vijay Govindarajan
- Departments of Cardiovascular Surgery (V.G., L.M., A.S., M.A.C., E.E.E., J.D., N.S.C., N.E.S., D.M.H., P.E.H., S.J.G., A.P., P.J.d.N.), Boston Children's Hospital, MA
- Surgery (V.G., D.M.H., P.E.H.), Harvard Medical School, Boston, MA
- Department of Internal Medicine, University of Texas Health Science Center at Houston (V.G.)
| | - Lauren Marshall
- Departments of Cardiovascular Surgery (V.G., L.M., A.S., M.A.C., E.E.E., J.D., N.S.C., N.E.S., D.M.H., P.E.H., S.J.G., A.P., P.J.d.N.), Boston Children's Hospital, MA
| | - Akshita Sahni
- Departments of Cardiovascular Surgery (V.G., L.M., A.S., M.A.C., E.E.E., J.D., N.S.C., N.E.S., D.M.H., P.E.H., S.J.G., A.P., P.J.d.N.), Boston Children's Hospital, MA
| | - Maria A Cetatoiu
- Departments of Cardiovascular Surgery (V.G., L.M., A.S., M.A.C., E.E.E., J.D., N.S.C., N.E.S., D.M.H., P.E.H., S.J.G., A.P., P.J.d.N.), Boston Children's Hospital, MA
| | - Emily E Eickhoff
- Departments of Cardiovascular Surgery (V.G., L.M., A.S., M.A.C., E.E.E., J.D., N.S.C., N.E.S., D.M.H., P.E.H., S.J.G., A.P., P.J.d.N.), Boston Children's Hospital, MA
| | - Jocelyn Davee
- Departments of Cardiovascular Surgery (V.G., L.M., A.S., M.A.C., E.E.E., J.D., N.S.C., N.E.S., D.M.H., P.E.H., S.J.G., A.P., P.J.d.N.), Boston Children's Hospital, MA
| | - Nicole St Clair
- Departments of Cardiovascular Surgery (V.G., L.M., A.S., M.A.C., E.E.E., J.D., N.S.C., N.E.S., D.M.H., P.E.H., S.J.G., A.P., P.J.d.N.), Boston Children's Hospital, MA
| | - Noah E Schulz
- Departments of Cardiovascular Surgery (V.G., L.M., A.S., M.A.C., E.E.E., J.D., N.S.C., N.E.S., D.M.H., P.E.H., S.J.G., A.P., P.J.d.N.), Boston Children's Hospital, MA
| | - David M Hoganson
- Departments of Cardiovascular Surgery (V.G., L.M., A.S., M.A.C., E.E.E., J.D., N.S.C., N.E.S., D.M.H., P.E.H., S.J.G., A.P., P.J.d.N.), Boston Children's Hospital, MA
- Surgery (V.G., D.M.H., P.E.H.), Harvard Medical School, Boston, MA
| | - Peter E Hammer
- Departments of Cardiovascular Surgery (V.G., L.M., A.S., M.A.C., E.E.E., J.D., N.S.C., N.E.S., D.M.H., P.E.H., S.J.G., A.P., P.J.d.N.), Boston Children's Hospital, MA
- Surgery (V.G., D.M.H., P.E.H.), Harvard Medical School, Boston, MA
| | - Sunil J Ghelani
- Departments of Cardiovascular Surgery (V.G., L.M., A.S., M.A.C., E.E.E., J.D., N.S.C., N.E.S., D.M.H., P.E.H., S.J.G., A.P., P.J.d.N.), Boston Children's Hospital, MA
- Cardiology (S.J.G., A.P., P.J.d.N., R.H.R.), Boston Children's Hospital, MA
| | - Ashwin Prakash
- Departments of Cardiovascular Surgery (V.G., L.M., A.S., M.A.C., E.E.E., J.D., N.S.C., N.E.S., D.M.H., P.E.H., S.J.G., A.P., P.J.d.N.), Boston Children's Hospital, MA
- Cardiology (S.J.G., A.P., P.J.d.N., R.H.R.), Boston Children's Hospital, MA
| | - Pedro J Del Nido
- Departments of Cardiovascular Surgery (V.G., L.M., A.S., M.A.C., E.E.E., J.D., N.S.C., N.E.S., D.M.H., P.E.H., S.J.G., A.P., P.J.d.N.), Boston Children's Hospital, MA
- Cardiology (S.J.G., A.P., P.J.d.N., R.H.R.), Boston Children's Hospital, MA
| | - Rahul H Rathod
- Cardiology (S.J.G., A.P., P.J.d.N., R.H.R.), Boston Children's Hospital, MA
- Departments of Pediatrics (R.H.R.), Harvard Medical School, Boston, MA
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Govindarajan V, Marshall L, Sahni A, Cetatoiu M, Eickhoff E, Davee J, St Clair N, Schulz N, Hoganson DM, Hammer PE, Ghelani S, Prakash A, Del Nido PJ, Rathod RH. Impact of Age-related change in Caval Flow Ratio on Hepatic Flow Distribution in Fontan. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.09.06.23295166. [PMID: 37732201 PMCID: PMC10508792 DOI: 10.1101/2023.09.06.23295166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
Background The Fontan operation is a palliative technique for patients born with single ventricle heart disease. The superior vena cava (SVC), inferior vena cava (IVC), and hepatic veins are connected to the pulmonary arteries in a total cavopulmonary connection by an extracardiac (EC) conduit or a lateral tunnel (LT) connection. A balanced hepatic flow distribution (HFD) to both lungs is essential to prevent pulmonary arteriovenous malformations and cyanosis. HFD is highly dependent on the local hemodynamics. Objective The effect of age-related changes in caval inflows on HFD was evaluated using cardiac MRI (CMR) data and patient-specific computational fluid dynamics (CFD) modeling. Methods SVC and IVC flow from 414 Fontan patients were collected to establish a relationship between SVC:IVC flow ratio and age. CFD modeling was performed in 60 (30 EC and 30 LT) patient models to quantify the HFD that corresponded to patient ages of 3, 8, and 15 years, respectively. Results SVC:IVC flow ratio inverted at ∼8 years of age, indicating a clear shift to lower body flow predominance. Our data showed that variation of HFD in response to age-related changes in caval inflows (SVC:IVC = 2,1, and 0.5 corresponded to ages 3, 8, and 15+ respectively) was not significant for EC but statistically significant for LT cohorts. For all three caval inflow ratios, a positive correlation existed between the IVC flow distribution to both the lungs and the HFD. However, as the SVC:IVC ratio changed from 2→0.5 (age 3→15+), the correlation's strength decreased from 0.87→0.64, due to potential flow perturbation as IVC flow momentum increased. Conclusion Our analysis provided quantitative insights into the impact of the changing caval inflows on Fontan's long-term HFD, highlighting the importance of including SVC:IVC variations over time to understand Fontan's long-term hemodynamics. These findings broaden our understanding of Fontan hemodynamics and patient outcomes. Clinical Perspective With improvement in standard of care and management of single ventricle patients with Fontan physiology, the population of adults with Fontan circulation is increasing. Consequently, there is a clinical need to comprehend the impact of patient growth on Fontan hemodynamics. Using CMR data, we were able to quantify the relationship between changing caval inflows and somatic growth. We then used patient-specific computational flow modeling to quantify how this relationship affected the distribution of long-term hepatic flow in extracardiac and lateral tunnel Fontan types. Our findings demonstrated the significance of including SVC:IVC changes over time in CFD modeling to learn more about the long-term hemodynamics of Fontan. Fontan surgical approaches are increasingly planned and optimized using computational flow modeling. For a patient undergoing a Fontan procedure, the workflow presented in this study that takes into account the variations in Caval inflows over time can aid in predicting the long-term hemodynamics in a planned Fontan pathway.
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Corno AF, Owen MJ, Cangiani A, Hall EJC, Rona A. Physiological Fontan Procedure. Front Pediatr 2019; 7:196. [PMID: 31179252 PMCID: PMC6543709 DOI: 10.3389/fped.2019.00196] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 04/29/2019] [Indexed: 11/13/2022] Open
Abstract
Objective: The conventional Fontan circulation deviates the superior vena cava (SVC = 1/3 of the systemic venous return) toward the right lung (3/5 of total lung volume) and the inferior vena cava (IVC = 2/3 of the systemic venous return) toward the left lung (2/5 of total lung volume). A "physiological" Fontan deviating the SVC toward the left lung and the IVC toward the right lung was compared with the conventional setting by computational fluid dynamics, studying whether this setting achieves a more favorable hemodynamics than the conventional Fontan circulation. Materials and Methods: An in-silico 3D parametric model of the Fontan procedure was developed using idealized vascular geometries with invariant sizes of SVC, IVC, right pulmonary artery (RPA), and left pulmonary artery (LPA), steady inflow velocities at IVC and SVC, and constant equal outflow pressures at RPA and LPA. These parameters were set to perform finite-volume incompressible steady flow simulations, assuming a single-phase, Newtonian, isothermal, laminar blood flow. Numerically converged finite-volume mass and momentum flow balances determined the inlet pressures and the outflow rates. Numerical closed-path integration of energy fluxes across domain boundaries determined the flow energy loss rate through the Fontan circulation. The comparison evaluated: (1) mean IVC pressure; (2) energy loss rate; (3) kinetic energy maximum value throughout the domain volume. Results: The comparison of the physiological vs. conventional Fontan provided these results: (1) mean IVC pressure 13.9 vs. 14.1 mmHg (= 0.2 mmHg reduction); (2) energy loss rate 5.55 vs. 6.61 mW (= 16% reduction); (3) maximum kinetic energy 283 vs. 396 J/m3 (= 29% reduction). Conclusions: A more physiological flow distribution is accompanied by a reduction of mean IVC pressure and by substantial reductions of energy loss rate and of peak kinetic energy. The potential clinical impact of these hemodynamic changes in reducing the incidence and severity of the adverse long-term effects of the Fontan circulation, in particular liver failure and protein-losing enteropathy, still remains to be assessed and will be the subject of future work.
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Affiliation(s)
| | - Matt J. Owen
- University of Leicester, Leicester, United Kingdom
| | - Andrea Cangiani
- School of Mathematical Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Edward J. C. Hall
- School of Mathematical Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Aldo Rona
- University of Leicester, Leicester, United Kingdom
- Department of Engineering, University of Leicester, Leicester, United Kingdom
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