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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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In Vitro Measurement of Hepatic Flow Distribution in Fontan Vascular Conduits: Towards Rapid Validation Techniques. J Biomech 2022; 137:111092. [DOI: 10.1016/j.jbiomech.2022.111092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 04/08/2022] [Accepted: 04/08/2022] [Indexed: 11/24/2022]
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Kim B, Nguyen P, Loke YH, Cleveland V, Liu X, Mass P, Hibino N, Olivieri L, Krieger A. CorFix: Virtual Reality Cardiac Surgical Planning Software for Designing Patient-Specific Vascular Grafts: Development and Pilot Usability Study (Preprint). JMIR Cardio 2021; 6:e35488. [PMID: 35713940 PMCID: PMC9250062 DOI: 10.2196/35488] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 05/05/2022] [Accepted: 05/17/2022] [Indexed: 11/17/2022] Open
Abstract
Background Patients with single ventricle heart defects receive 3 stages of operations culminating in the Fontan procedure. During the Fontan procedure, a vascular graft is sutured between the inferior vena cava and pulmonary artery to divert deoxygenated blood flow to the lungs via passive flow. Customizing the graft configuration can maximize the long-term benefits. However, planning patient-specific procedures has several challenges, including the ability for physicians to customize grafts and evaluate their hemodynamic performance. Objective The aim of this study was to develop a virtual reality (VR) Fontan graft modeling and evaluation software for physicians. A user study was performed to achieve 2 additional goals: (1) to evaluate the software when used by medical doctors and engineers, and (2) to explore the impact of viewing hemodynamic simulation results in numerical and graphical formats. Methods A total of 5 medical professionals including 4 physicians (1 fourth-year resident, 1 third-year cardiac fellow, 1 pediatric intensivist, and 1 pediatric cardiac surgeon) and 1 biomedical engineer voluntarily participated in the study. The study was pre-scripted to minimize the variability of the interactions between the experimenter and the participants. All participants were trained to use the VR gear and our software, CorFix. Each participant designed 1 bifurcated and 1 tube-shaped Fontan graft for a single patient. A hemodynamic performance evaluation was then completed, allowing the participants to further modify their tube-shaped design. The design time and hemodynamic performance for each graft design were recorded. At the end of the study, all participants were provided surveys to evaluate the usability and learnability of the software and rate the intensity of VR sickness. Results The average times for creating 1 bifurcated and 1 tube-shaped graft after a single 10-minute training session were 13.40 and 5.49 minutes, respectively, with 3 out 5 bifurcated and 1 out of 5 tube-shaped graft designs being in the benchmark range of hepatic flow distribution. Reviewing hemodynamic performance results and modifying the tube-shaped design took an average time of 2.92 minutes. Participants who modified their tube-shaped graft designs were able to improve the nonphysiologic wall shear stress (WSS) percentage by 7.02%. All tube-shaped graft designs improved the WSS percentage compared to the native surgical case of the patient. None of the designs met the benchmark indexed power loss. Conclusions VR graft design software can quickly be taught to physicians with no engineering background or VR experience. Improving the CorFix system could improve performance of the users in customizing and optimizing grafts for patients. With graphical visualization, physicians were able to improve WSS percentage of a tube-shaped graft, lowering the chance of thrombosis. Bifurcated graft designs showed potential strength in better flow split to the lungs, reducing the risk for pulmonary arteriovenous malformations.
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Affiliation(s)
- Byeol Kim
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, United States
| | - Phong Nguyen
- Department of Computer Science, University of Maryland, College Park, MD, United States
| | - Yue-Hin Loke
- Division of Cardiology, Children's National Hospital, Washington, DC, United States
| | - Vincent Cleveland
- Division of Cardiology, Children's National Hospital, Washington, DC, United States
| | - Xiaolong Liu
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, United States
| | - Paige Mass
- Division of Cardiology, Children's National Hospital, Washington, DC, United States
| | - Narutoshi Hibino
- Department of Surgery, University of Chicago, Chicago, IL, United States
| | - Laura Olivieri
- Division of Cardiology, Children's National Hospital, Washington, DC, United States
| | - Axel Krieger
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, United States
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Imai K, Hoashi T, Okuda N, Ohuchi H, Kurosaki K, Ichikawa H. Impact of bilateral bidirectional Glenn anastomosis on staged Fontan strategy and Fontan circulation. Eur J Cardiothorac Surg 2021; 60:930-938. [PMID: 33895850 DOI: 10.1093/ejcts/ezab162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Revised: 02/06/2021] [Accepted: 02/22/2021] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVES The aim of this study was to identify the impact of bilateral bidirectional Glenn (BBDG) anastomosis on staged Fontan strategy and late Fontan circulation. METHODS Of 267 patients who underwent bidirectional Glenn prior to Fontan completion between 1989 and 2013, 62 patients (23%) who underwent BBDG were enrolled in this study. Age at operation was 0.84 years (25th-75th percentile: 0.58-1.39). Thirty-three patients had heterotaxy syndrome (53%). The mean follow-up period was 12.7 ± 8.1 (max. 30.6) years. RESULTS The overall survival rate at 15 years was 73%. Although 49 patients (79.0%) went on to Fontan completion, 12 patients (19.4%) died without achieving it. Thrombus formation and poor development in a central pulmonary artery were not observed, but obstruction of the superior vena cava (SVC) occurred in 8 patients (13%), mainly those with right atrial isomerism (P = 0.037). SVC obstruction was not, however, a risk factor for mortality (P = 0.097) or Fontan completion (P = 0.41). The shape of BBDG anastomosis, symmetricity of pulmonary blood flow, impingement of caval blood flow returning from the superior and inferior vena cavae or coexisting interrupted inferior vena cava with azygos or hemi-azygos continuation did not affect late Fontan outcomes, such as overall survival, freedom from protein-losing enteropathy or pulmonary arterio-venous malformation rates. CONCLUSIONS SVC obstruction after BBDG frequently occurred, mainly in patients with right atrial isomerism; however, its direct impact on prognosis or achieving Fontan completion was not identified. Once Fontan circulation was established, the arrangement of the Fontan pathway did not affect late Fontan outcomes.
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Affiliation(s)
- Kenta Imai
- Department of Pediatric Cardiovascular Surgery, National Cerebral and Cardiovascular Center, Suita, Osaka, Japan
| | - Takaya Hoashi
- Department of Pediatric Cardiovascular Surgery, National Cerebral and Cardiovascular Center, Suita, Osaka, Japan
| | - Naoki Okuda
- Department of Pediatric Cardiovascular Surgery, National Cerebral and Cardiovascular Center, Suita, Osaka, Japan
| | - Hideo Ohuchi
- Department of Pediatric Cardiology, National Cerebral and Cardiovascular Center, Suita, Osaka, Japan
| | - Kenichi Kurosaki
- Department of Pediatric Cardiology, National Cerebral and Cardiovascular Center, Suita, Osaka, Japan
| | - Hajime Ichikawa
- Department of Pediatric Cardiovascular Surgery, National Cerebral and Cardiovascular Center, Suita, Osaka, Japan
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Rijnberg FM, van der Woude SFS, van Assen HC, Juffermans JF, Hazekamp MG, Jongbloed MRM, Kenjeres S, Lamb HJ, Westenberg JJM, Wentzel JJ, Roest AAW. Non-uniform mixing of hepatic venous flow and inferior vena cava flow in the Fontan conduit. J R Soc Interface 2021; 18:20201027. [PMID: 33823607 PMCID: PMC8086942 DOI: 10.1098/rsif.2020.1027] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Fontan patients require a balanced hepatic blood flow distribution (HFD) to prevent pulmonary arteriovenous malformations. Currently, HFD is quantified by tracking Fontan conduit flow, assuming hepatic venous (HV) flow to be uniformly distributed within the Fontan conduit. However, this assumption may be unvalid leading to inaccuracies in HFD quantification with potential clinical impact. The aim of this study was to (i) assess the mixing of HV flow and inferior vena caval (IVC) flow within the Fontan conduit and (ii) quantify HFD by directly tracking HV flow and quantitatively comparing results with the conventional approach. Patient-specific, time-resolved computational fluid dynamic models of 15 total cavopulmonary connections were generated, including the HV and subhepatic IVC. Mixing of HV and IVC flow, on a scale between 0 (no mixing) and 1 (perfect mixing), was assessed at the caudal and cranial Fontan conduit. HFD was quantified by tracking particles from the caudal (HFDcaudal conduit) and cranial (HFDcranial conduit) conduit and from the hepatic veins (HFDHV). HV flow was non-uniformly distributed at both the caudal (mean mixing 0.66 ± 0.13) and cranial (mean 0.79 ± 0.11) level within the Fontan conduit. On a cohort level, differences in HFD between methods were significant but small; HFDHV (51.0 ± 20.6%) versus HFDcaudal conduit (48.2 ± 21.9%, p = 0.033) or HFDcranial conduit (48.0 ± 21.9%, p = 0.044). However, individual absolute differences of 8.2–14.9% in HFD were observed in 4/15 patients. HV flow is non-uniformly distributed within the Fontan conduit. Substantial individual inaccuracies in HFD quantification were observed in a subset of patients with potential clinical impact.
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Affiliation(s)
- Friso M Rijnberg
- Department of Cardiothoracic Surgery, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Hans C van Assen
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Joe F Juffermans
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Mark G Hazekamp
- Department of Cardiothoracic Surgery, Leiden University Medical Center, Leiden, The Netherlands
| | - Monique R M Jongbloed
- Department of Cardiology and Anatomy and Embryology, Leiden University Medical Center, Leiden, The Netherlands
| | - Sasa Kenjeres
- Department of Chemical Engineering, Faculty of Applied Sciences, Delft University of Technology and J. M. Burgerscentrum Research School for Fluid Mechanics, Delft, The Netherlands
| | - Hildo J Lamb
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Jos J M Westenberg
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Jolanda J Wentzel
- Department of Cardiology, Biomedical Engineering, Erasmus MC, Rotterdam, The Netherlands
| | - Arno A W Roest
- Department of Pediatric Cardiology, Leiden University Medical Center, Leiden, The Netherlands
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Reduced scan time and superior image quality with 3D flow MRI compared to 4D flow MRI for hemodynamic evaluation of the Fontan pathway. Sci Rep 2021; 11:6507. [PMID: 33753790 PMCID: PMC7985309 DOI: 10.1038/s41598-021-85936-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 03/03/2021] [Indexed: 12/14/2022] Open
Abstract
Long scan times prohibit a widespread clinical applicability of 4D flow MRI in Fontan patients. As pulsatility in the Fontan pathway is minimal during the cardiac cycle, acquiring non-ECG gated 3D flow MRI may result in a reduction of scan time while accurately obtaining time-averaged clinical parameters in comparison with 2D and 4D flow MRI. Thirty-two Fontan patients prospectively underwent 2D (reference), 3D and 4D flow MRI of the Fontan pathway. Multiple clinical parameters were assessed from time-averaged flow rates, including the right-to-left pulmonary flow distribution (main endpoint) and systemic-to-pulmonary collateral flow (SPCF). A ten-fold reduction in scan time was achieved [4D flow 15.9 min (SD 2.7 min) and 3D flow 1.6 min (SD 7.8 s), p < 0.001] with a superior signal-to-noise ratio [mean ratio of SNRs 1.7 (0.8), p < 0.001] and vessel sharpness [mean ratio 1.2 (0.4), p = 0.01] with 3D flow. Compared to 2D flow, good–excellent agreement was shown for mean flow rates (ICC 0.82–0.96) and right-to-left pulmonary flow distribution (ICC 0.97). SPCF derived from 3D flow showed good agreement with that from 4D flow (ICC 0.86). 3D flow MRI allows for obtaining time-averaged flow rates and derived clinical parameters in the Fontan pathway with good–excellent agreement with 2D and 4D flow, but with a tenfold reduction in scan time and significantly improved image quality compared to 4D flow.
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Wei ZA, Ratnayaka K, Si B, Singh-Gryzbon S, Cetatoiu MA, Fogel MA, Slesnick T, Yoganathan AP, Nigro JJ. An Anterior Anastomosis for the Modified Fontan Connection: A Hemodynamic Analysis. Semin Thorac Cardiovasc Surg 2021; 33:816-823. [PMID: 33662555 DOI: 10.1053/j.semtcvs.2021.01.056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 01/05/2021] [Indexed: 12/25/2022]
Abstract
This hemodynamic feasibility study examined total cavopulmonary connection (TCPC) designs connecting the extracardiac conduit to the anterior surface of pulmonary arteries (PAs) or superior vena cava (SVC) rather than to the inferior PA surface (traditional TCPC). The study involved twenty-five consecutive Fontan patients meeting inclusion criteria from a single institution. A virtual surgical platform mimicked the completed traditional TCPC and generated three anterior anastomosis designs: Anterior-PA, Middle-SVC, and SVC-Inn (Inn: innominate vein). Hemodynamic performance of anterior anastomosis designs was compared with the traditional TCPC regarding indexed power loss (iPL) and hepatic flow distribution (HFD). Compared to the traditional TCPC, the Anterior-PA design produces a similar iPL. The Middle-SVC design is also similar, though the iPL difference is positively correlated with the anastomosing height. The SVC-Inn design had significantly more iPL. The three anterior anastomosis designs did not have a significant difference in HFD (from traditional TCPC). Pulmonary flow distribution (PFD) has a stronger correlation with HFD from the anterior anastomosis designs than the traditional TCPC. This hemodynamic feasibility study examined anterior anastomosis, extracardiac TCPC designs that may offer surgeons clinical dexterity. The Anterior-PA design may be equivalent to the traditional TCPC. Fontan extracardiac conduit anastomosis just superior to the PAs (Middle-SVC) also preserves hemodynamic performance and avoids direct PA anastomosis. These designs could simplify surgical Fontan completion, and may particularly benefit patients requiring surgical dissection, having atypical PA orientation, or after PA stent angioplasty.
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Affiliation(s)
- Zhenglun Alan Wei
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia; Department of Biomedical Engineering, University of Massachusetts Lowell, Lowell, Massachusetts
| | - Kanishka Ratnayaka
- Division of Pediatric Cardiology, Rady Children's Hospital and UC San Diego School of Medicine, San Diego, California
| | - Biao Si
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia
| | - Shelly Singh-Gryzbon
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia
| | | | - Mark A Fogel
- Division of Cardiology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Timothy Slesnick
- Emory University School of Medicine, Children's Healthcare of Atlanta, Atlanta, Georgia
| | - Ajit P Yoganathan
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia.
| | - John J Nigro
- Division of Cardiovascular Surgery, Rady Children's Hospital and UC San Diego School of Medicine, San Diego, California
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McHugo VS, Nolke L, Delassus P, MaCarthy E, McMahon CJ, Morris L. The impact of compliance on Stage 2 uni-ventricular heart circulation: An experimental assessment of the Bidirectional Glenn. Med Eng Phys 2020; 84:184-192. [PMID: 32977917 DOI: 10.1016/j.medengphy.2020.07.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 03/11/2020] [Accepted: 07/13/2020] [Indexed: 11/30/2022]
Abstract
The Bidirectional Glenn (BDG) or cavopulmonary connection is typically undertaken to volume unload the single ventricle in an effort to preserve ventricular and atrioventricular valve function. The geometry of this surgical palliation has been shown to influence the fluid energy loss as well as the distribution of flow that enters through the superior vena cava. In-vitro and in-silico studies to date have been performed on rigid wall models, while this investigation looks at the impact of flexible thin walled models versus rigid walls. Rigid and compliant models of two patient-specific Glenn geometries were fabricated and tested under various flow conditions, within a biosimulator capable of replicating patient specific flow conditions. It was found that the compliant models exhibit greater levels of energy loss compared to the rigid models. Along with these findings greater levels of turbulence was found in both compliant models compared to their rigid counterparts under ultrasound examinations. This shows that vessel compliance has a significant impact on the hemodynamics within hypoplastic left heart syndrome.
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Affiliation(s)
- V S McHugo
- Department of Mechanical and Industrial Engineering (GMIT), Galway Medical Technology Centre, Ireland.
| | - L Nolke
- Department of Pediatric Cardiology Our Lady's Children's Hospital Crumlin, Dublin, Ireland; University College Dublin School of Medicine, Belfield, Dublin, Ireland
| | - P Delassus
- Department of Mechanical and Industrial Engineering (GMIT), Galway Medical Technology Centre, Ireland
| | - E MaCarthy
- Department of Mechanical and Industrial Engineering (GMIT), Galway Medical Technology Centre, Ireland
| | - C J McMahon
- Department of Pediatric Cardiology Our Lady's Children's Hospital Crumlin, Dublin, Ireland; University College Dublin School of Medicine, Belfield, Dublin, Ireland.
| | - L Morris
- Department of Mechanical and Industrial Engineering (GMIT), Galway Medical Technology Centre, Ireland.
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Imai K, Hoashi T, Shimada M, Komori M, Nakata T, Kurosaki K, Ichikawa H. Long-term Outcomes of Extracardiac Total Cavopulmonary Connection for Apicocaval Juxtaposition. Ann Thorac Surg 2020; 112:1326-1333. [PMID: 32979374 DOI: 10.1016/j.athoracsur.2020.07.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 07/03/2020] [Accepted: 07/13/2020] [Indexed: 11/30/2022]
Abstract
BACKGROUND The long-term outcomes of a total cavopulmonary connection (TCPC) with an extracardiac conduit (ECC) for patients with apicocaval juxtaposition (ACJ) remain unclear. METHODS A total of 38 patients with ACJ who underwent TCPC with ECC between 1998 and 2014 were enrolled in this study. For 19 patients with a superior vena cava - inferior vena cava contralateral position, a long-curved route rounding the opposite side of the apex was selected (CC group). For 11 patients with a superior vena cava-inferior vena cava ipsilateral position, a long-curved route was principally selected (IC group); however, a short, straight route was selected for 8 patients because there was sufficient space behind the ventricular apex (IS group). RESULTS Follow-up was completed in all patients, with a mean follow-up duration of 13.2 ± 4.9 years. The angles of the caudal conduit anastomosis site measured from the frontal view of cineangiography had significantly straightened in the CC group from 1 year to 15 years (P < .05) and in the IC group from 1 year to 10 years (P < .05). There were 2 late mortalities and 6 reoperations during follow-up. Overall survival and freedom from reoperation rates at 15 years were 95% and 82%, respectively. There were no conduit-related or route-related complications such as death, reoperations, pulmonary venous obstructions, conduit obstructions, or pulmonary arteriovenous malformations in any of the groups. CONCLUSIONS Even though chronologic geometric changes of curved ECCs were observed, TCPC with ECC for patients with ACJ can be safely applied without conduit- or route-related complications in long-term follow-up.
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Affiliation(s)
- Kenta Imai
- Department of Pediatric Cardiovascular Surgery, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Takaya Hoashi
- Department of Pediatric Cardiovascular Surgery, National Cerebral and Cardiovascular Center, Osaka, Japan.
| | - Masatoshi Shimada
- Department of Pediatric Cardiovascular Surgery, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Motoki Komori
- Department of Pediatric Cardiovascular Surgery, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Tomohiro Nakata
- Department of Pediatric Cardiovascular Surgery, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Kenichi Kurosaki
- Department of Cardiology, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Hajime Ichikawa
- Department of Pediatric Cardiovascular Surgery, National Cerebral and Cardiovascular Center, Osaka, Japan
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Hemodynamic Effects of A Simplified Venturi Conduit for Fontan Circulation: A Pilot, In Silico Analysis. Sci Rep 2020; 10:817. [PMID: 31964953 PMCID: PMC6972950 DOI: 10.1038/s41598-020-57634-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Accepted: 12/31/2019] [Indexed: 12/28/2022] Open
Abstract
Objectives: To study the effects of a self-powered Fontan circulation in both idealized Fontan models and patient-specific models. Methods: In silico, a conduit with a nozzle was introduced from ascending aorta into the anastomosis of superior vena cava and pulmonary artery. Computational fluid dynamics (CFD) simulation was applied to calculate the fluid fields of models. Three 3-dimentional idealized models with different offsets were reconstructed by computer-aided design to evaluate the effects of the self-powered conduit. Furthermore, to validate the effects in patient-specific models, the conduit was introduced to three reconstructed models with different offsets. Results: The pressures at superior venae cavae and inferior venae cavae were decreased in both idealized models (0.4 mmHg) and patient-specific models (0.7 mmHg). In idealized models, the flows to left lungs were decreased (70%) by the jets from the conduits. However, in patient-specific models, the reductions of blood to the left lungs were relatively limited (30%) comparing to idealized models. Conclusions: CFD simulation was applied to analyze the effectiveness of the Fontan self-powered conduit. This self-powered conduit may help to decrease the venae cavae pressures and increase the flow to pulmonary arteries.
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Bastkowski R, Bindermann R, Brockmeier K, Weiss K, Maintz D, Giese D. Respiration Dependency of Caval Blood Flow in Patients with Fontan Circulation: Quantification Using 5D Flow MRI. Radiol Cardiothorac Imaging 2019; 1:e190005. [PMID: 33778515 PMCID: PMC7977808 DOI: 10.1148/ryct.2019190005] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 06/26/2019] [Accepted: 07/30/2019] [Indexed: 06/12/2023]
Abstract
PURPOSE To measure respiration-dependent blood flow in the total cavopulmonary connection (TCPC) of patients with Fontan circulation by using free-running, fully self-gated five-dimensional (5D) flow MRI. MATERIALS AND METHODS From July to November 2018, 10 volunteers (six female volunteers, mean age, 25.1 years ± 4.4 [standard deviation]) and six patients with Fontan circulation (two female patients, mean age, 19.7 years ± 7.5) with a TCPC were examined by using a cardiac- and respiration-resolved three-directional and three-dimensional phase-contrast MRI sequence (hereafter, 5D flow MRI). This prospective study was conducted with approval of the local ethics committee, and written informed consent was obtained from all participants and/or their representative. 5D flow data were acquired during free breathing. Data were reconstructed into 15-20 heart phases and four respiratory phases: end-expiration, inspiration, end-inspiration, and expiration. Respiration-dependent stroke volumes (SVs) and particle traces were analyzed from the caval circulation of volunteers and patients with Fontan circulation. Statistical analysis was performed by using parametric tests and scatterplots. RESULTS The respiration dependency of caval blood flow was evaluated in all participants and was significantly elevated in patients with Fontan circulation as compared with volunteers. In patients, SV in the inferior vena cava (IVC) showed variations of 120% between inspiration and expiration (P = .002). The flow distribution in the IVC and superior vena cava among the four respiratory phases was differentiated by 20% (range, 9%-30%) and 4% (range, 0%-13%), respectively. CONCLUSION Hemodynamic parameters (volume flow and blood flow distribution) throughout the cardiac and respiratory cycle can be measured using a single scan, potentially providing further insights into the Fontan circulation.© RSNA, 2019Supplemental material is available for this article.
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Impact of Flow Differentials According to Cardiac and Respiratory Cycles on Three Types of Fontan Operation. Pediatr Cardiol 2018; 39:1144-1155. [PMID: 29671004 DOI: 10.1007/s00246-018-1872-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 03/22/2018] [Indexed: 10/17/2022]
Abstract
Few hemodynamic comparison studies on various types of Fontan operation have been reported. The objective of this study was to perform hemodynamic comparisons for flow size and volume in three types of Fontan operation: atriopulmonary connection (APC), lateral tunnel (LT), and extracardiac conduit (ECC). Forty patients with Fontan operation (8 with APC Fontan, 22 with LT Fontan, and 10 with ECC Fontan) were enrolled. Velocity time integral (VTI) and average peak velocity (APV) were assessed according to cardiac and respiratory cycles in SVC, IVC, hepatic vein, conduit, LPA, and RPA using direct intravenous Doppler echocardiography. During each cardiac cycle in APC, VTI and APV between inspiration and expiration did not show significant differences in SVC, IVC, HV, LPA, or RPA. During each cardiac cycle in LT and ECC, VTI and APV between inspiration and expiration showed significant differences in all native vessels. The gap between S and D wave in APC was the highest, followed by that in LT. It was the lowest in ECC regardless of inspiration or expiration. Hepatic reverse VTI and APV in APC showed significant decreases compared to those in VC and PA during inspiration and expiration. Flow size and volume in APC were more influenced by cardiac cycle. Those in LT were moderately influenced by both respiratory cycle and cardiac cycle while those in ECC were more influenced by respiratory cycle. APC Fontan has hemodynamic inefficiency with prominent reverse flow. However, total cavopulmonary connection (TCPC) Fontan has more hemodynamic efficiency without prominent reverse flows.
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Rijnberg FM, Hazekamp MG, Wentzel JJ, de Koning PJ, Westenberg JJ, Jongbloed MR, Blom NA, Roest AA. Energetics of Blood Flow in Cardiovascular Disease. Circulation 2018; 137:2393-2407. [DOI: 10.1161/circulationaha.117.033359] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
| | | | - Jolanda J. Wentzel
- Leiden University Medical Center, The Netherlands. Department of Biomechanical Engineering, Erasmus Medical Center, Rotterdam, The Netherlands (J.J.W.)
| | | | | | | | - Nico A. Blom
- Department of Pediatric Cardiology (N.A.B., A.A.W.R.)
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Impact of the location of the fenestration on Fontan circulation haemodynamics: a three-dimensional, computational model study. Cardiol Young 2017; 27:1289-1294. [PMID: 28376950 DOI: 10.1017/s1047951117000099] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
OBJECTIVES There is no consensus or theoretical explanation regarding the optimal location for the fenestration during the Fontan operation. We investigated the impact of the location of the fenestration on Fontan haemodynamics using a three-dimensional Fontan model in various physiological conditions. METHODS A three-dimensional Fontan model was constructed on the basis of CT images, and a 4-mm-diameter fenestration was located between the extracardiac Fontan conduit and the right atrium at three positions: superior, middle, and inferior part of the conduit. Haemodynamics in the Fontan route were analysed using a three-dimensional computational fluid dynamic model in realistic physiological conditions, which were predicted using a lumped parameter model of the cardiovascular system. The respiratory effect of the caval flow was taken into account. The flow rate through the fenestration, the effect of lowering the central venous pressure, and wall shear stress in the Fontan circuit were evaluated under central venous pressures of 10, 15, and 20 mmHg. The pulse power index and pulsatile energy loss index were calculated as energy loss indices. RESULTS Under all central venous pressures, the middle-part fenestration demonstrated the most significant effect on enhancing the flow rate through the fenestration while lowering the central venous pressure. The middle-part fenestration produced the highest time-averaged wall shear stress, pressure pulse index, and pulsatile energy loss index. CONCLUSIONS Despite slightly elevated energy loss, the middle-part fenestration most significantly increased cardiac output and lowered central venous pressure under respiration in the Fontan circulation.
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Udink ten Cate FEA, Trieschmann U, Germund I, Hannes T, Emmel M, Bennink G, Sreeram N. Stenting the Fontan pathway in paediatric patients with obstructed extracardiac conduits. Heart 2017; 103:1111-1116. [DOI: 10.1136/heartjnl-2016-310511] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 01/09/2017] [Accepted: 01/16/2017] [Indexed: 11/04/2022] Open
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Kamphuis VP, Westenberg JJM, van der Palen RLF, Blom NA, de Roos A, van der Geest R, Elbaz MSM, Roest AAW. Unravelling cardiovascular disease using four dimensional flow cardiovascular magnetic resonance. Int J Cardiovasc Imaging 2016; 33:1069-1081. [PMID: 27888419 PMCID: PMC5489572 DOI: 10.1007/s10554-016-1031-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 11/21/2016] [Indexed: 11/29/2022]
Abstract
Knowledge of normal and abnormal flow patterns in the human cardiovascular system increases our understanding of normal physiology and may help unravel the complex pathophysiological mechanisms leading to cardiovascular disease. Four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) has emerged as a suitable technique that enables visualization of in vivo blood flow patterns and quantification of parameters that could potentially be of prognostic value in the disease process. In this review, current image processing tools that are used for comprehensive visualization and quantification of blood flow and energy distribution in the heart and great vessels will be discussed. Also, imaging biomarkers extracted from 4D flow CMR will be reviewed that have been shown to distinguish between normal and abnormal flow patterns. Furthermore, current applications of 4D flow CMR in the heart and great vessels will be discussed, showing its potential as an additional diagnostic modality which could aid in disease management and timing of surgical intervention.
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Affiliation(s)
- Vivian P Kamphuis
- Division of Pediatric Cardiology, Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands.,Netherlands Heart Institute, Utrecht, The Netherlands
| | - Jos J M Westenberg
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.
| | - Roel L F van der Palen
- Division of Pediatric Cardiology, Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands
| | - Nico A Blom
- Division of Pediatric Cardiology, Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands
| | - Albert de Roos
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Rob van der Geest
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Mohammed S M Elbaz
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Arno A W Roest
- Division of Pediatric Cardiology, Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands
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Jarvis K, Schnell S, Barker AJ, Garcia J, Lorenz R, Rose M, Chowdhary V, Carr J, Robinson JD, Rigsby CK, Markl M. Evaluation of blood flow distribution asymmetry and vascular geometry in patients with Fontan circulation using 4-D flow MRI. Pediatr Radiol 2016; 46:1507-19. [PMID: 27350377 PMCID: PMC5039076 DOI: 10.1007/s00247-016-3654-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 05/04/2016] [Accepted: 06/02/2016] [Indexed: 11/26/2022]
Abstract
BACKGROUND Asymmetrical caval to pulmonary blood flow is suspected to cause complications in patients with Fontan circulation. The aim of this study was to test the feasibility of 4-D flow MRI for characterizing the relationship between 3-D blood flow distribution and vascular geometry. OBJECTIVE We hypothesized that both flow distribution and geometry can be calculated with low interobserver variability and will detect a direct relationship between flow distribution and Fontan geometry. MATERIALS AND METHODS Four-dimensional flow MRI was acquired in 10 Fontan patients (age: 16 ± 4 years [mean ± standard deviation], range: 9-21 years). The Fontan connection was isolated by 3-D segmentation to evaluate flow distribution from the inferior vena cava (IVC) and superior vena cava (SVC) to the left and right pulmonary arteries (LPA, RPA) and to characterize geometry (cross-sectional area, caval offset, vessel angle). RESULTS Flow distribution results indicated SVC flow tended toward the RPA while IVC flow was more evenly distributed (SVC to RPA: 78% ± 28 [9-100], IVC to LPA: 54% ± 28 [4-98]). There was a significant relationship between pulmonary artery cross-sectional area and flow distribution (IVC to RPA: R(2)=0.50, P=0.02; SVC to LPA: R(2)=0.81, P=0.0004). Good agreement was found between observers and for flow distribution when compared to net flow values. CONCLUSION Four-dimensional flow MRI was able to detect relationships between flow distribution and vessel geometry. Future studies are warranted to investigate the potential of patient specific hemodynamic analysis to improve diagnostic capability.
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Affiliation(s)
- Kelly Jarvis
- Department of Radiology, Feinberg School of Medicine, Northwestern University, 737 N. Michigan Ave., Suite 1600, Chicago, IL, 60611, USA.
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Chicago, IL, USA.
| | - Susanne Schnell
- Department of Radiology, Feinberg School of Medicine, Northwestern University, 737 N. Michigan Ave., Suite 1600, Chicago, IL, 60611, USA
| | - Alex J Barker
- Department of Radiology, Feinberg School of Medicine, Northwestern University, 737 N. Michigan Ave., Suite 1600, Chicago, IL, 60611, USA
| | - Julio Garcia
- Department of Radiology, Feinberg School of Medicine, Northwestern University, 737 N. Michigan Ave., Suite 1600, Chicago, IL, 60611, USA
| | - Ramona Lorenz
- Department of Radiology, University Medical Center Freiburg, Freiburg, Germany
| | - Michael Rose
- Department of Medical Imaging, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Varun Chowdhary
- Department of Radiology, Feinberg School of Medicine, Northwestern University, 737 N. Michigan Ave., Suite 1600, Chicago, IL, 60611, USA
| | - James Carr
- Department of Radiology, Feinberg School of Medicine, Northwestern University, 737 N. Michigan Ave., Suite 1600, Chicago, IL, 60611, USA
| | - Joshua D Robinson
- Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
- Division of Cardiology, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Cynthia K Rigsby
- Department of Radiology, Feinberg School of Medicine, Northwestern University, 737 N. Michigan Ave., Suite 1600, Chicago, IL, 60611, USA
- Department of Medical Imaging, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Michael Markl
- Department of Radiology, Feinberg School of Medicine, Northwestern University, 737 N. Michigan Ave., Suite 1600, Chicago, IL, 60611, USA
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Chicago, IL, USA
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Haemodynamic impact of stent implantation for lateral tunnel Fontan stenosis: a patient-specific computational assessment. Cardiol Young 2016; 26:116-26. [PMID: 25712430 DOI: 10.1017/s1047951114002765] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND The physiological importance of the lateral tunnel stenosis in the Fontan pathway for children with single ventricle physiology can be difficult to determine. The impact of the stenosis and stent implantation on total cavopulmonary connection resistance has not been characterized, and there are no clear guidelines for intervention. Methods and results A computational framework for haemodynamic assessment of stent implantation in patients with lateral tunnel stenosis was developed. Cardiac magnetic resonances images were reconstructed to obtain total cavopulmonary connection anatomies before stent implantation. Stents with 2-mm diameter increments were virtually implanted in each patient to understand the impact of stent diameter. Numerical simulations were performed in all geometries with patient-specific flow rates. Exercise conditions were simulated by doubling and tripling the lateral tunnel flow rate. The resulting total cavopulmonary connection vascular resistances were computed. A total of six patients (age: 14.4 ± 3.1 years) with lateral tunnel stenosis were included for preliminary analysis. The mean baseline resistance was 1.54 ± 1.08 WU · m(2) and dependent on the stenosis diameter. It was further exacerbated during exercise. It was observed that utilising a stent with a larger diameter lowered the resistance, but the resistance reduction diminished at larger diameters. CONCLUSIONS Using a computational framework to assess the severity of lateral tunnel stenosis and the haemodynamic impact of stent implantation, it was observed that stenosis in the lateral tunnel pathway was associated with higher total cavopulmonary connection resistance than unobstructed pathways, which was exacerbated during exercise. Stent implantation could reduce the resistance, but the improvement was specific to the minimum diameter.
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George SM, Eckert LM, Martin DR, Giddens DP. Hemodynamics in Normal and Diseased Livers: Application of Image-Based Computational Models. Cardiovasc Eng Technol 2014; 6:80-91. [DOI: 10.1007/s13239-014-0195-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 09/10/2014] [Indexed: 01/14/2023]
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Tang E, Restrepo M, Haggerty CM, Mirabella L, Bethel J, Whitehead KK, Fogel MA, Yoganathan AP. Geometric characterization of patient-specific total cavopulmonary connections and its relationship to hemodynamics. JACC Cardiovasc Imaging 2014; 7:215-24. [PMID: 24529885 DOI: 10.1016/j.jcmg.2013.12.010] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 11/27/2013] [Accepted: 12/03/2013] [Indexed: 11/25/2022]
Abstract
Total cavopulmonary connection (TCPC) geometries have great variability. Geometric features, such as diameter, connection angle, and distance between vessels, are hypothesized to affect the energetics and flow dynamics within the connection. This study aimed to identify important geometric characteristics that can influence TCPC hemodynamics. Anatomies from 108 consecutive patients were reconstructed from cardiac magnetic resonance (CMR) images and analyzed for their geometric features. Vessel flow rates were computed from phase contrast CMR. Computational fluid dynamics simulations were carried out to quantify the indexed power loss and hepatic flow distribution. TCPC indexed power loss correlated inversely with minimum Fontan pathway (FP), left pulmonary artery, and right pulmonary artery diameters. Cardiac index correlated with minimum FP diameter and superior vena cava (SVC) minimum/maximum diameter ratio. Hepatic flow distribution correlated with caval offset, pulmonary flow distribution, and the angle between FP and SVC. These correlations can have important implications for future connection design and patient follow-up.
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Affiliation(s)
- Elaine Tang
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia
| | - Maria Restrepo
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia
| | - Christopher M Haggerty
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia
| | - Lucia Mirabella
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia
| | | | - Kevin K Whitehead
- Division of Cardiology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Mark A Fogel
- Division of Cardiology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Ajit P Yoganathan
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia.
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Dori Y, Sathanandam S, Glatz AC, Gillespie MJ, Rome JJ. Catheter approach to redirect hepatic venous return for treatment of unilateral pulmonary arteriovenous malformations after fontan. Catheter Cardiovasc Interv 2014; 84:86-93. [PMID: 24327433 DOI: 10.1002/ccd.25326] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 10/08/2013] [Accepted: 11/28/2013] [Indexed: 11/08/2022]
Abstract
OBJECTIVES The goal of this report is to describe a percutaneous approach to rerouting hepatic venous return in patients who developed progressive cyanosis due to unilateral pulmonary arteriovenous malformations (PAVM) after the total cavopulmonary connection (TCPC) operation. BACKGROUND Unilateral PAVM can develop in patients after TCPC operation when there is unequal distribution of hepatic venous return between the two lungs. This often results in progressive cyanosis and the need for surgical re-intervention. A percutaneous based approach for rerouting hepatic venous return has never been described. METHODS We retrospectively reviewed the clinical data on four patients who underwent percutaneous rerouting procedures. One patient with a misaligned TCPC underwent realignment of the circuit with a bare metal stent. In three patients a combination of bare metal and covered stents were needed to achieve the desired results. RESULTS The rerouting procedures were successful in all patients with significant improvement in oxygen saturation from a median of 75% (range 55-80%) to a median of 90% (range 84-92%) (P = 0.02). There were no recorded short term or intermediate term complications with maximum follow-up time of 43 months. CONCLUSIONS Percutaneous rerouting of hepatic venous flow is feasible and should be considered when a surgical approach is not possible; this strategy may serve as a viable alternative to complex operative approaches in select cases. Furthermore studies are needed to determine the long-term efficacy of this procedure.
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Affiliation(s)
- Yoav Dori
- Division of Cardiology, The Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, Pennsylvania
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23
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Haggerty CM, Restrepo M, Tang E, de Zélicourt DA, Sundareswaran KS, Mirabella L, Bethel J, Whitehead KK, Fogel MA, Yoganathan AP. Fontan hemodynamics from 100 patient-specific cardiac magnetic resonance studies: a computational fluid dynamics analysis. J Thorac Cardiovasc Surg 2013; 148:1481-9. [PMID: 24507891 DOI: 10.1016/j.jtcvs.2013.11.060] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 10/27/2013] [Accepted: 11/15/2013] [Indexed: 11/28/2022]
Abstract
OBJECTIVES This study sought to quantify average hemodynamic metrics of the Fontan connection as reference for future investigations, compare connection types (intra-atrial vs extracardiac), and identify functional correlates using computational fluid dynamics in a large patient-specific cohort. Fontan hemodynamics, particularly power losses, are hypothesized to vary considerably among patients with a single ventricle and adversely affect systemic hemodynamics and ventricular function if suboptimal. METHODS Fontan connection models were created from cardiac magnetic resonance scans for 100 patients. Phase velocity cardiac magnetic resonance in the aorta, vena cavae, and pulmonary arteries was used to prescribe patient-specific time-averaged flow boundary conditions for computational fluid dynamics with a customized, validated solver. Comparison with 4-dimensional cardiac magnetic resonance velocity data from selected patients was used to provide additional verification of simulations. Indexed Fontan power loss, connection resistance, and hepatic flow distribution were quantified and correlated with systemic patient characteristics. RESULTS Indexed power loss varied by 2 orders of magnitude, whereas, on average, Fontan resistance was 15% to 20% of published values of pulmonary vascular resistance in single ventricles. A significant inverse relationship was observed between indexed power loss and both systemic venous flow and cardiac index. Comparison by connection type showed no differences between intra-atrial and extracardiac connections. Instead, the least efficient connections revealed adverse consequences from localized Fontan pathway stenosis. CONCLUSIONS Fontan power loss varies from patient to patient, and elevated levels are correlated with lower systemic flow and cardiac index. Fontan connection type does not influence hemodynamic efficiency, but an undersized or stenosed Fontan pathway or pulmonary arteries can be highly dissipative.
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Affiliation(s)
- Christopher M Haggerty
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, Ga
| | - Maria Restrepo
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, Ga
| | - Elaine Tang
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, Ga
| | - Diane A de Zélicourt
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, Ga; Interface Group, Institute of Physiology, University of Zürich, Zürich, Switzerland
| | - Kartik S Sundareswaran
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, Ga
| | - Lucia Mirabella
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, Ga
| | | | - Kevin K Whitehead
- Division of Cardiology, Children's Hospital of Philadelphia, Philadelphia, Pa
| | - Mark A Fogel
- Division of Cardiology, Children's Hospital of Philadelphia, Philadelphia, Pa
| | - Ajit P Yoganathan
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, Ga.
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Mock circulatory system of the Fontan circulation to study respiration effects on venous flow behavior. ASAIO J 2013; 59:253-60. [PMID: 23644612 DOI: 10.1097/mat.0b013e318288a2ab] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
We describe an in vitro model of the Fontan circulation with respiration to study subdiaphragmatic venous flow behavior. The venous and arterial connections of a total cavopulmonary connection (TCPC) test section were coupled with a physical lumped parameter (LP) model of the circulation. Intrathoracic and subdiaphragmatic pressure changes associated with normal breathing were applied. This system was tuned for two patients (5 years, 0.67 m2; 10 years, 1.2 m2) to physiological values. System function was verified by comparison to the analytical model on which it was based and by consistency with published clinical measurements. Overall, subdiaphragmatic venous flow was influenced by respiration. Flow within the arteries and veins increased during inspiration but decreased during expiration, with retrograde flow in the inferior venous territories. System pressures and flows showed close agreement with the analytical LP model (p < 0.05). The ratio of the flow rates occurring during inspiration to expiration were within the clinical range of values reported elsewhere. The approach used to set up and control the model was effective and provided reasonable comparisons with clinical data.
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Postsurgical Comparison of Pulsatile Hemodynamics in Five Unique Total Cavopulmonary Connections: Identifying Ideal Connection Strategies. Ann Thorac Surg 2013; 96:1398-1404. [DOI: 10.1016/j.athoracsur.2013.05.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 05/08/2013] [Accepted: 05/10/2013] [Indexed: 11/24/2022]
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Hong H, Dur O, Zhang H, Zhu Z, Pekkan K, Liu J. Fontan conversion templates: patient-specific hemodynamic performance of the lateral tunnel versus the intraatrial conduit with fenestration. Pediatr Cardiol 2013; 34:1447-54. [PMID: 23475255 DOI: 10.1007/s00246-013-0669-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Accepted: 02/11/2013] [Indexed: 11/25/2022]
Abstract
Intraatrial-conduit Fontan is considered a modification of both extracardiac and lateral-tunnel Fontan. In this study, the patient-specific hemodynamic performance of intraatrial-conduit and lateral-tunnel Fontan with fenestration, considered as conversion templates, was investigated based on the authors' patient cohort. Pulsatile computational fluid dynamics simulations were performed using patient-specific models of intraatrial-conduit and lateral-tunnel Fontan patients. Real-time "simultaneous" inferior and superior vena cava, pulmonary artery, and fenestration flow waveforms were acquired from ultrasound. Multiple hemodynamic performance indices were investigated, with particular focus on evaluation of the pulsatile flow performance. Power loss inside the lateral-tunnel Fontan appeared to be significantly higher than with the intraatrial-conduit Fontan for patient-specific cardiac output and normalized connection size. Inclusion of the 4-mm fenestration at a 0.24 L/min mean flow resulted in a lower cavopulmonary pressure gradient and less time-averaged power loss for both Fontan connections. Flow structures within the intraatrial conduit were notability more uniform than within the lateral tunnel. Hepatic flow majorly favored the left lung in both surgical connections: conversion from lateral-tunnel to intraatrial-conduit Fontan resulted in better hemodynamics with less power loss, a lower pressure gradient, and fewer stagnant flow zones along the conduit. This patient-specific computational case study demonstrated superior hemodynamics of intraatrial-conduit Fontan over those of lateral-tunnel Fontan with or without fenestration and improved performance after conversion of the lateral tunnel to the intraatrial conduit. The geometry-specific effect of the nonuniform hepatic flow distribution may motivate new rationales for the surgical design.
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Affiliation(s)
- Haifa Hong
- The Cardiothoracic Surgery Department, Shanghai Children's Medical Center, Medical School Shanghai Jiaotong University, 1678 Dongfang Road, Shanghai 200127, China
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Haggerty CM, Kanter KR, Restrepo M, de Zélicourt DA, Parks WJ, Rossignac J, Fogel MA, Yoganathan AP. Simulating hemodynamics of the Fontan Y-graft based on patient-specific in vivo connections. J Thorac Cardiovasc Surg 2013; 145:663-70. [PMID: 22560957 PMCID: PMC3517690 DOI: 10.1016/j.jtcvs.2012.03.076] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Revised: 02/05/2012] [Accepted: 03/12/2012] [Indexed: 11/23/2022]
Abstract
BACKGROUND Using a bifurcated Y-graft as the Fontan baffle is hypothesized to streamline and improve flow dynamics through the total cavopulmonary connection (TCPC). This study conducted numerical simulations to evaluate this hypothesis using postoperative data from 5 patients. METHODS Patients were imaged with cardiac magnetic resonance or computed tomography after receiving a bifurcated aorto-iliac Y-graft as their Fontan conduit. Numerical simulations were performed using in vivo flow rates, as well as 2 levels of simulated exercise. Two TCPC models were virtually created for each patient to serve as the basis for hemodynamic comparison. Comparative metrics included connection flow resistance and inferior vena caval flow distribution. RESULTS Results demonstrate good hemodynamic outcomes for the Y-graft options. The consistency of inferior vena caval flow distribution was improved over TCPC controls, whereas the connection resistances were generally no different from the TCPC values, except for 1 case in which there was a marked improvement under both resting and exercise conditions. Examination of the connection hemodynamics as they relate to surgical Y-graft implementation identified critical strategies and modifications that are needed to potentially realize the theoretical efficiency of such bifurcated connection designs. CONCLUSIONS Five consecutive patients received a Y-graft connection to complete their Fontan procedure with positive hemodynamic results. Refining the surgical technique for implementation should result in further energetic improvements that may help improve long-term outcomes.
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Affiliation(s)
- Christopher M. Haggerty
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, GA
| | - Kirk R. Kanter
- Division of Cardiothoracic Surgery, Department of Surgery, Emory University School of Medicine and Children's Healthcare of Atlanta at Egleston, Atlanta, GA
| | - Maria Restrepo
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, GA
| | - Diane A. de Zélicourt
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, GA
| | - W. James Parks
- Division of Pediatric Cardiology, Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta at Egleston, Atlanta, GA
| | - Jarek Rossignac
- College of Computing, Georgia Institute of Technology, Atlanta, GA
| | - Mark A. Fogel
- Division of Cardiology, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Ajit P. Yoganathan
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, GA
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Pennati G, Corsini C, Hsia TY, Migliavacca F. Computational fluid dynamics models and congenital heart diseases. Front Pediatr 2013; 1:4. [PMID: 24432298 PMCID: PMC3882907 DOI: 10.3389/fped.2013.00004] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Accepted: 02/01/2013] [Indexed: 11/13/2022] Open
Abstract
Mathematical modeling is a powerful tool to investigate hemodynamics of the circulatory system. With improving imaging techniques and detailed clinical investigations, it is now possible to construct patient-specific models of reconstructive surgeries for the treatment of congenital heart diseases. These models can help clinicians to better understand the hemodynamic behavior of different surgical options for a treated patient. This review outlines recent advances in mathematical modeling in congenital heart diseases, the discoveries and limitations these models present, and future directions that are on the horizon.
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Affiliation(s)
- Giancarlo Pennati
- Laboratory of Biological Structure Mechanics, Chemistry, Materials and Chemical Engineering Department "Giulio Natta", Politecnico di Milano Milano, Italy
| | - Chiara Corsini
- Laboratory of Biological Structure Mechanics, Chemistry, Materials and Chemical Engineering Department "Giulio Natta", Politecnico di Milano Milano, Italy
| | - Tain-Yen Hsia
- Cardiac Unit, Great Ormond Street Hospital for Children London, UK
| | - Francesco Migliavacca
- Laboratory of Biological Structure Mechanics, Chemistry, Materials and Chemical Engineering Department "Giulio Natta", Politecnico di Milano Milano, Italy
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Bächler P, Valverde I, Pinochet N, Nordmeyer S, Kuehne T, Crelier G, Tejos C, Irarrazaval P, Beerbaum P, Uribe S. Caval blood flow distribution in patients with Fontan circulation: quantification by using particle traces from 4D flow MR imaging. Radiology 2013; 267:67-75. [PMID: 23297331 DOI: 10.1148/radiol.12120778] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To validate the use of particle traces derived from four-dimensional (4D) flow magnetic resonance (MR) imaging to quantify in vivo the caval flow contribution to the pulmonary arteries (PAs) in patients who had been treated with the Fontan procedure. MATERIALS AND METHODS The institutional review boards approved this study, and informed consent was obtained. Twelve healthy volunteers and 10 patients with Fontan circulation were evaluated. The particle trace method consists of creating a region of interest (ROI) on a blood vessel, which is used to emit particles with a temporal resolution of approximately 40 msec. The flow distribution, as a percentage, is then estimated by counting the particles arriving to different ROIs. To validate this method, two independent observers used particle traces to calculate the flow contribution of the PA to its branches in volunteers and compared it with the contribution estimated by measuring net forward flow volume (reference method). After the method was validated, caval flow contributions were quantified in patients. Statistical analysis was performed with nonparametric tests and Bland-Altman plots. P < .05 was considered to indicate a significant difference. RESULTS Estimation of flow contributions by using particle traces was equivalent to estimation by using the reference method. Mean flow contribution of the PA to the right PA in volunteers was 54% ± 3 (standard deviation) with the reference method versus 54% ± 3 with the particle trace method for observer 1 (P = .4) and 54% ± 4 versus 54% ± 4 for observer 2 (P = .6). In patients with Fontan circulation, 87% ± 13 of the superior vena cava blood flowed to the right PA (range, 63%-100%), whereas 55% ± 19 of the inferior vena cava blood flowed to the left PA (range, 22%-82%). CONCLUSION Particle traces derived from 4D flow MR imaging enable in vivo quantification of the caval flow distribution to the PAs in patients with Fontan circulation. This method might allow the identification of patients at risk of developing complications secondary to uneven flow distribution. SUPPLEMENTAL MATERIAL http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12120778/-/DC1.
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Affiliation(s)
- Pablo Bächler
- Department of Radiology, School of Medicine, Pontificia Universidad Católica de Chile, Marcoleta 367, Santiago 8330024, Chile
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Yang W, Feinstein JA, Shadden SC, Vignon-Clementel IE, Marsden AL. Optimization of a Y-Graft Design for Improved Hepatic Flow Distribution in the Fontan Circulation. J Biomech Eng 2012; 135:011002. [DOI: 10.1115/1.4023089] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Single ventricle heart defects are among the most serious congenital heart diseases, and are uniformly fatal if left untreated. Typically, a three-staged surgical course, consisting of the Norwood, Glenn, and Fontan surgeries is performed, after which the superior vena cava (SVC) and inferior vena cava (IVC) are directly connected to the pulmonary arteries (PA). In an attempt to improve hemodynamic performance and hepatic flow distribution (HFD) of Fontan patients, a novel Y-shaped graft has recently been proposed to replace the traditional tube-shaped extracardiac grafts. Previous studies have demonstrated that the Y-graft is a promising design with the potential to reduce energy loss and improve HFD. However these studies also found suboptimal Y-graft performance in some patient models. The goal of this work is to determine whether performance can be improved in these models through further design optimization. Geometric and hemodynamic factors that influence the HFD have not been sufficiently investigated in previous work, particularly for the Y-graft. In this work, we couple Lagrangian particle tracking to an optimal design framework to study the effects of boundary conditions and geometry on HFD. Specifically, we investigate the potential of using a Y-graft design with unequal branch diameters to improve hepatic distribution under a highly uneven RPA/LPA flow split. As expected, the resulting optimal Y-graft geometry largely depends on the pulmonary flow split for a particular patient. The unequal branch design is demonstrated to be unnecessary under most conditions, as it is possible to achieve the same or better performance with equal-sized branches. Two patient-specific examples show that optimization-derived Y-grafts effectively improve the HFD, compared to initial nonoptimized designs using equal branch diameters. An instance of constrained optimization shows that energy efficiency slightly increases with increasing branch size for the Y-graft, but that a smaller branch size is preferred when a proximal anastomosis is needed to achieve optimal HFD.
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Affiliation(s)
- Weiguang Yang
- Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA 92093 e-mail:
| | | | - Shawn C. Shadden
- Mechanical, Materials, and
Aerospace Engineering, Illinois Institute of Technology, Chicago, IL 60616 e-mail:
| | | | - Alison L. Marsden
- Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA 92093 e-mail:
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Tang E, Haggerty CM, Khiabani RH, de Zélicourt D, Kanter J, Sotiropoulos F, Fogel MA, Yoganathan AP. Numerical and experimental investigation of pulsatile hemodynamics in the total cavopulmonary connection. J Biomech 2012. [PMID: 23200904 DOI: 10.1016/j.jbiomech.2012.11.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Computational fluid dynamics (CFD) tools have been extensively applied to study the hemodynamics in the total cavopulmonary connection (TCPC) in patients with only a single functioning ventricle. Without the contraction of a sub-pulmonary ventricle, pulsatility of flow through this connection is low and variable across patients, which is usually neglected in most numerical modeling studies. Recent studies suggest that such pulsatility can be non-negligible and can be important in hemodynamic predictions. The goal of this work is to compare the results of an in-house numerical methodology for simulating pulsatile TCPC flow with experimental results. Digital particle image velocimetry (DPIV) was acquired on TCPC in vitro models to evaluate the capability of the CFD tool in predicting pulsatile TCPC flow fields. In vitro hemodynamic measurements were used to compare the numerical prediction of power loss across the connection. The results demonstrated the complexity of the pulsatile TCPC flow fields and the validity of the numerical approach in simulating pulsatile TCPC flow dynamics in both idealized and complex patient specific models.
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Affiliation(s)
- Elaine Tang
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United States
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32
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Extracardiac conduit Fontan procedure versus intra-atrial lateral tunnel Fontan procedure. Gen Thorac Cardiovasc Surg 2012; 60:792-5. [PMID: 23229999 DOI: 10.1007/s11748-012-0161-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Indexed: 11/27/2022]
Abstract
The Fontan procedure has provided excellent surgical palliation for patients with various types of univentricular hearts, and it has evolved over time. Among many modifications, the lateral tunnel Fontan connection (LTF) and the extracardiac Fontan connection (ECF) are currently the most popular techniques for completing the total cavopulmonary connection. The advantages and disadvantages of both techniques are reviewed here. The advantages of the ECF includes adaptability to all types of univentricular hearts, ease of construction without aortic cross clamping and fewer atrial suture lines. The advantages of the LTF include the ability to complete Fontan circulation in young, very small patients with potential for growth. This review also compares post-operative arrhythmias and fluid dynamics associated with both techniques.
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Kanter KR, Haggerty CM, Restrepo M, de Zelicourt DA, Rossignac J, Parks WJ, Yoganathan AP. Preliminary clinical experience with a bifurcated Y-graft Fontan procedure--a feasibility study. J Thorac Cardiovasc Surg 2012; 144:383-9. [PMID: 22698555 PMCID: PMC3433765 DOI: 10.1016/j.jtcvs.2012.05.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2011] [Revised: 04/18/2012] [Accepted: 05/09/2012] [Indexed: 10/28/2022]
Abstract
OBJECTIVE Optimizing flow and diminishing power loss in the Fontan circuit can improve hemodynamic efficiency, potentially improving the long-term outcomes. Computerized modeling has predicted improved energetics with a Y-graft Fontan. METHODS From August to December 2010, 6 consecutive children underwent completion Fontan (n=3) or Fontan revision (n=3) using a bifurcated polytetrafluoroethylene Y-graft (18×9×9 mm in 2, 20×10×10 mm in 4) connecting the inferior vena cava to the right and left pulmonary arteries with separate graft limbs. The patents underwent magnetic resonance imaging (n=5) or computed tomography (n=1). Computational fluid dynamics assessed Fontan hemodynamics, power loss, and inferior vena cava flow splits to the branch pulmonary arteries. The clinical parameters were compared with those from 12 patients immediately preceding the present series who had undergone a lateral Fontan procedure. RESULTS Despite longer crossclamp and bypass times (not statistically significant), the Y-graft Fontan patients had postoperative courses similar to those of the conventional Fontan patients. Other than 2 early readmissions for pleural effusions managed with diuretics, at 6 to 12 months of follow-up (mean, 8 months), all 6 patients had done well. Postoperative flow modeling demonstrated a balanced distribution of inferior vena cava flow to both pulmonary arteries with minimal flow disturbance. Improvements in hemodynamics and efficiency were noted when the Y-graft branches were anastomosed distally and aligned tangentially with the branch pulmonary arteries. CONCLUSIONS The present preliminary surgical experience has demonstrated the clinical feasibility of the bifurcated Y-graft Fontan. Computational fluid dynamics showed acceptable hemodynamics with low calculated power losses and a balanced distribution of inferior vena cava flow to the pulmonary arteries as long as the branch grafts were anastomosed distally.
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Affiliation(s)
- Kirk R Kanter
- Division of Cardiothoracic Surgery, Department of Surgery, Emory University School of Medicine and Children's Healthcare of Atlanta at Egleston, Atlanta, GA 30322, USA.
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Haggerty CM, de Zélicourt DA, Restrepo M, Rossignac J, Spray TL, Kanter KR, Fogel MA, Yoganathan AP. Comparing pre- and post-operative Fontan hemodynamic simulations: implications for the reliability of surgical planning. Ann Biomed Eng 2012; 40:2639-51. [PMID: 22777126 DOI: 10.1007/s10439-012-0614-4] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Accepted: 06/27/2012] [Indexed: 11/25/2022]
Abstract
Virtual modeling of cardiothoracic surgery is a new paradigm that allows for systematic exploration of various operative strategies and uses engineering principles to predict the optimal patient-specific plan. This study investigates the predictive accuracy of such methods for the surgical palliation of single ventricle heart defects. Computational fluid dynamics (CFD)-based surgical planning was used to model the Fontan procedure for four patients prior to surgery. The objective for each was to identify the operative strategy that best distributed hepatic blood flow to the pulmonary arteries. Post-operative magnetic resonance data were acquired to compare (via CFD) the post-operative hemodynamics with predictions. Despite variations in physiologic boundary conditions (e.g., cardiac output, venous flows) and the exact geometry of the surgical baffle, sufficient agreement was observed with respect to hepatic flow distribution (90% confidence interval-14 ± 4.3% difference). There was also good agreement of flow-normalized energetic efficiency predictions (19 ± 4.8% error). The hemodynamic outcomes of prospective patient-specific surgical planning of the Fontan procedure are described for the first time with good quantitative comparisons between preoperatively predicted and postoperative simulations. These results demonstrate that surgical planning can be a useful tool for single ventricle cardiothoracic surgery with the ability to deliver significant clinical impact.
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Affiliation(s)
- Christopher M Haggerty
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, Atlanta, GA 30332, USA
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Pulsatile venous waveform quality affects the conduit performance in functional and "failing" Fontan circulations. Cardiol Young 2012; 22:251-62. [PMID: 22008697 DOI: 10.1017/s1047951111001491] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE To investigate the effect of pulsatility of venous flow waveform in the inferior and superior caval vessels on the performance of functional and "failing" Fontan patients based on two primary performance measures - the conduit power loss and the distribution of inferior caval flow (hepatic factors) to the lungs. METHODS Doppler angiography flows were acquired from two typical extra-cardiac conduit "failing" Fontan patients, aged 13 and 25 years, with ventricle dysfunction. Using computational fluid dynamics, haemodynamic efficiencies of "failing", functional, and in vitro-generated mechanically assisted venous flow waveforms were evaluated inside an idealised total cavopulmonary connection with a caval offset. To investigate the effect of venous pulsatility alone, cardiac output was normalised to 3 litres per minute in all cases. To quantify the pulsatile behaviour of venous flows, two new performance indices were suggested. RESULTS Variations in the pulsatile content of venous waveforms altered the conduit efficiency notably. High-frequency and low-amplitude oscillations lowered the pulsatile component of the power losses in "failing" Fontan flow waveforms. Owing to the offset geometry, hepatic flow distribution depended strongly on the ratio of time-dependent caval flows and the pulsatility content rather than mixing at the junction. "Failing" Fontan flow waveforms exhibited less balanced hepatic flow distribution to lungs. CONCLUSIONS The haemodynamic efficiency of single-ventricle circulation depends strongly on the pulsatility of venous flow waveforms. The proposed performance indices can be calculated easily in the clinical setting in efforts to better quantify the energy efficiency of Fontan venous waveforms in pulsatile settings.
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Yang W, Vignon-Clementel IE, Troianowski G, Reddy VM, Feinstein JA, Marsden AL. Hepatic blood flow distribution and performance in conventional and novel Y-graft Fontan geometries: A case series computational fluid dynamics study. J Thorac Cardiovasc Surg 2012; 143:1086-97. [DOI: 10.1016/j.jtcvs.2011.06.042] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Revised: 05/13/2011] [Accepted: 06/27/2011] [Indexed: 11/15/2022]
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37
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Quantification of caval flow contribution to the lungs in vivo after total cavopulmonary connection with 4-dimensional flow magnetic resonance imaging. J Thorac Cardiovasc Surg 2012; 143:742-3. [DOI: 10.1016/j.jtcvs.2011.11.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Accepted: 11/07/2011] [Indexed: 11/18/2022]
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Lara M, Chen CY, Mannor P, Dur O, Menon PG, Yoganathan AP, Pekkan K. Hemodynamics of the Hepatic Venous Three-Vessel Confluences Using Particle Image Velocimetry. Ann Biomed Eng 2011; 39:2398-416. [DOI: 10.1007/s10439-011-0326-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2010] [Accepted: 05/10/2011] [Indexed: 11/27/2022]
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39
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Pennati G, Corsini C, Cosentino D, Hsia TY, Luisi VS, Dubini G, Migliavacca F. Boundary conditions of patient-specific fluid dynamics modelling of cavopulmonary connections: possible adaptation of pulmonary resistances results in a critical issue for a virtual surgical planning. Interface Focus 2011; 1:297-307. [PMID: 22670201 DOI: 10.1098/rsfs.2010.0021] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Accepted: 02/14/2011] [Indexed: 11/12/2022] Open
Abstract
Cavopulmonary connections are surgical procedures used to treat a variety of complex congenital cardiac defects. Virtual pre-operative planning based on in silico patient-specific modelling might become a powerful tool in the surgical decision-making process. For this purpose, three-dimensional models can be easily developed from medical imaging data to investigate individual haemodynamics. However, the definition of patient-specific boundary conditions is still a crucial issue. The present study describes an approach to evaluate the vascular impedance of the right and left lungs on the basis of pre-operative clinical data and numerical simulations. Computational fluid dynamics techniques are applied to a patient with a bidirectional cavopulmonary anastomosis, who later underwent a total cavopulmonary connection (TCPC). Multi-scale models describing the surgical region and the lungs are adopted, while the flow rates measured in the venae cavae are used at the model inlets. Pre-operative and post-operative conditions are investigated; namely, TCPC haemodynamics, which are predicted using patient-specific pre-operative boundary conditions, indicates that the pre-operative balanced lung resistances are not compatible with the TCPC measured flows, suggesting that the pulmonary vascular impedances changed individually after the surgery. These modifications might be the consequence of adaptation to the altered pulmonary blood flows.
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Affiliation(s)
- Giancarlo Pennati
- Laboratory of Biological Structure Mechanics, Structural Engineering Department , Politecnico di Milano , Piazza Leonardo da Vinci, 32, 20133 Milan , Italy
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de Zélicourt DA, Marsden A, Fogel MA, Yoganathan AP. Imaging and patient-specific simulations for the Fontan surgery: current methodologies and clinical applications. PROGRESS IN PEDIATRIC CARDIOLOGY 2010; 30:31-44. [PMID: 25620865 PMCID: PMC4302339 DOI: 10.1016/j.ppedcard.2010.09.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Diane A. de Zélicourt
- Wallace H. Coulter School of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA
| | - Alison Marsden
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA
| | - Mark A. Fogel
- Division of Cardiology, Children’s Hospital of Philadelphia, Philadelphia, PA
| | - Ajit P. Yoganathan
- Wallace H. Coulter School of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA
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