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A Comparison of Vessel Patch Materials in Tetralogy of Fallot Patients Using Virtual Surgery Techniques. Ann Biomed Eng 2023:10.1007/s10439-023-03144-x. [PMID: 36723833 DOI: 10.1007/s10439-023-03144-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 12/25/2022] [Indexed: 02/02/2023]
Abstract
Tetralogy of Fallot (ToF) is characterized by stenosis causing partial obstruction of the right ventricular outflow tract, typically alleviated through the surgical application of a vessel patch made from a biocompatible material. In this study, we use computational simulations to compare the mechanical performance of four patch materials for various stenosis locations. Nine idealized pre-operative ToF geometries were created by imposing symmetrical stenoses on each of three anatomical sub-regions of the pulmonary arteries of three patients with previously repaired ToF. A virtual surgery methodology was implemented to replicate the steps of vessel de-pressurization, surgical patching, and subsequent vessel expansion after reperfusion. Significant differences in patch average stress (p < 0.001) were found between patch materials. Biological patch materials (porcine xenopericardium, human pericardium) exhibited higher patch stresses in comparison to synthetic patch materials (Dacron and PTFE). Observed differences were consistent across the various stenosis locations and were insensitive to patient anatomy.
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An In Vitro Circulatory Loop Model of the Pediatric Right Ventricular Outflow Tract as a Platform for Valve Evaluation. Cardiovasc Eng Technol 2022; 14:217-229. [PMID: 36456745 DOI: 10.1007/s13239-022-00648-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 11/11/2022] [Indexed: 12/04/2022]
Abstract
PURPOSE Tetralogy of Fallot and other conditions affecting the right ventricular outflow tract (RVOT) are common in pediatric patients, but there is a lack of quantitative comparison among techniques for repairing or replacing the pulmonary valve. The aim of this study was to develop a robust in vitro system for quantifying flow conditions after various RVOT interventions. METHODS An infant-sized mock circulatory loop that includes a 3D-printed RVOT anatomical model was developed to evaluate flow conditions after different simulated surgical repairs. Physiologically correct flow and pressure were achieved with custom compliant tubing and a tunable flow restrictor. Pressure gradient, flow regurgitation, and coaptation height were measured for two monocusp leaflet designs after tuning the system with a 12 mm Hancock valved conduit. RESULTS Measurements were repeatable across multiple samples of two different monocusp designs, with the wider leaflet in the 50% backwall model consistently exhibiting lower pressure gradient but higher regurgitation compared to the leaflet in the 40% backwall model. Coaptation height was measured via direct visualization with endoscopic cameras, revealing a shorter area of contact for the wider leaflet (3.3-4.0 mm) compared to the narrower one (4.3 mm). CONCLUSION The 3D-printed RVOT anatomical model and in vitro pulmonary circulatory loop developed in this work provide a platform for planning and evaluating surgical interventions in the pediatric population. Measurements of regurgitation, pressure gradient, and coaptation provide a quantitative basis for comparison among different valve designs and positions.
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Dong ML, Azarine A, Haddad F, Amsallem M, Kim YW, Yang W, Fadel E, Aubrege L, Loecher M, Ennis D, Pavec JL, Vignon-Clementel I, Feinstein JA, Mercier O, Marsden AL. 4D flow cardiovascular magnetic resonance recovery profiles following pulmonary endarterectomy in chronic thromboembolic pulmonary hypertension. J Cardiovasc Magn Reson 2022; 24:59. [PMID: 36372884 PMCID: PMC9661778 DOI: 10.1186/s12968-022-00893-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Accepted: 10/04/2022] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Four-dimensional flow cardiovascular magnetic resonance imaging (4D flow CMR) allows comprehensive assessment of pulmonary artery (PA) flow dynamics. Few studies have characterized longitudinal changes in pulmonary flow dynamics and right ventricular (RV) recovery following a pulmonary endarterectomy (PEA) for patients with chronic thromboembolic pulmonary hypertension (CTEPH). This can provide novel insights of RV and PA dynamics during recovery. We investigated the longitudinal trajectory of 4D flow metrics following a PEA including velocity, vorticity, helicity, and PA vessel wall stiffness. METHODS Twenty patients with CTEPH underwent pre-PEA and > 6 months post-PEA CMR imaging including 4D flow CMR; right heart catheter measurements were performed in 18 of these patients. We developed a semi-automated pipeline to extract integrated 4D flow-derived main, left, and right PA (MPA, LPA, RPA) volumes, velocity flow profiles, and secondary flow profiles. We focused on secondary flow metrics of vorticity, volume fraction of positive helicity (clockwise rotation), and the helical flow index (HFI) that measures helicity intensity. RESULTS Mean PA pressures (mPAP), total pulmonary resistance (TPR), and normalized RV end-systolic volume (RVESV) decreased significantly post-PEA (P < 0.002). 4D flow-derived PA volumes decreased (P < 0.001) and stiffness, velocity, and vorticity increased (P < 0.01) post-PEA. Longitudinal improvements from pre- to post-PEA in mPAP were associated with longitudinal decreases in MPA area (r = 0.68, P = 0.002). Longitudinal improvements in TPR were associated with longitudinal increases in the maximum RPA HFI (r=-0.85, P < 0.001). Longitudinal improvements in RVESV were associated with longitudinal decreases in MPA fraction of positive helicity (r = 0.75, P = 0.003) and minimum MPA HFI (r=-0.72, P = 0.005). CONCLUSION We developed a semi-automated pipeline for analyzing 4D flow metrics of vessel stiffness and flow profiles. PEA was associated with changes in 4D flow metrics of PA flow profiles and vessel stiffness. Longitudinal analysis revealed that PA helicity was associated with pulmonary remodeling and RV reverse remodeling following a PEA.
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Affiliation(s)
- Melody L Dong
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Arshid Azarine
- Department of Radiology, Groupe Hospitalier Paris Saint-Joseph, Paris, France
- Pulmonary Hypertension: Pathophysiology and Novel Therapies, Marie Lannelongue Hospital, INSERM UMR-S 999, Le Plessis Robinson, France
| | - Francois Haddad
- Division of Cardiovascular Medicine, Stanford University, Stanford, CA, USA
| | - Myriam Amsallem
- Division of Cardiovascular Medicine, Stanford University, Stanford, CA, USA
| | - Young-Wouk Kim
- Department of Radiology, Groupe Hospitalier Paris Saint-Joseph, Paris, France
| | - Weiguang Yang
- Department of Pediatric Cardiology, Stanford University, Stanford, CA, USA
| | - Elie Fadel
- Biomedical Engineering Lab, Groupe Hospitalier Paris Saint-Joseph, Paris, France
- Department of Thoracic Surgery, Marie Lannelongue Hospital, Université Paris-Saclay, Le Plessis Robinson, France
- Pulmonary Hypertension: Pathophysiology and Novel Therapies, Marie Lannelongue Hospital, INSERM UMR-S 999, Le Plessis Robinson, France
| | - Laure Aubrege
- Biomedical Engineering Lab, Groupe Hospitalier Paris Saint-Joseph, Paris, France
| | - Michael Loecher
- Department of Radiology, Stanford University, Stanford, CA, USA
| | - Daniel Ennis
- Department of Radiology, Stanford University, Stanford, CA, USA
| | - Jérôme Le Pavec
- Department of Respirology, Marie Lannelongue Hospital, Le Plessis Robinson, France
- Pulmonary Hypertension: Pathophysiology and Novel Therapies, Marie Lannelongue Hospital, INSERM UMR-S 999, Le Plessis Robinson, France
| | | | | | - Olaf Mercier
- Biomedical Engineering Lab, Groupe Hospitalier Paris Saint-Joseph, Paris, France
- Department of Thoracic Surgery, Marie Lannelongue Hospital, Université Paris-Saclay, Le Plessis Robinson, France
- Pulmonary Hypertension: Pathophysiology and Novel Therapies, Marie Lannelongue Hospital, INSERM UMR-S 999, Le Plessis Robinson, France
| | - Alison L Marsden
- Department of Bioengineering, Stanford University, Stanford, CA, USA.
- Department of Pediatric Cardiology, Stanford University, Stanford, CA, USA.
- Department of Bioengineering and Pediatric Cardiology, Stanford University, Stanford, CA, USA.
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In Silico Hemodynamics and Filtering Evaluation of a Commercial Embolic Protection Device. Ann Biomed Eng 2021; 49:2659-2670. [PMID: 34405319 DOI: 10.1007/s10439-021-02846-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 08/01/2021] [Indexed: 10/20/2022]
Abstract
During the last years, several kinds of Embolic Protection Devices (EPD) have been developed, with the aim of minimizing complication caused by thrombi generated during Carotid Artery Stenting (CAS). These devices are capable of capturing small particles generated during the intervention, avoiding cerebral stroke and improving the outcomes of the surgery. However, they have associated complications, like the increase on flow resistance associated by their use or the lack of knowledge on their actual filtration efficiency for thrombi of low size. Current work proposes a validated computational methodology in order to predict the hemodynamic features and filtering efficiency of a commercial EPD. It will be observed how Computational Fluid Dynamics predicts pressure drop with fair agreement with the experimental measurements. Finally, this work analyzes the filtration efficiency and the influence of the distribution of injected particles on this parameter. The capabilities of the filter for retaining particles of diameter below the pore size is, additionally, discussed.
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