1
|
Donik Ž, Li W, Nnate B, Pugar JA, Nguyen N, Milner R, Cerda E, Pocivavsek L, Kramberger J. A computational study of artery curvature and endograft oversize influence on seal zone behavior in endovascular aortic repair. Comput Biol Med 2024; 178:108745. [PMID: 38901185 PMCID: PMC11317088 DOI: 10.1016/j.compbiomed.2024.108745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 05/18/2024] [Accepted: 06/08/2024] [Indexed: 06/22/2024]
Abstract
Thoracic endovascular aortic repair (TEVAR) is a minimally invasive procedure involving the placement of an endograft inside the dissection or an aneurysm to direct blood flow and prevent rupture. A significant challenge in endovascular surgery is the geometrical mismatch between the endograft and the artery, which can lead to endoleak formation, a condition where blood leaks between the endograft and the vessel wall. This study uses computational modeling to investigate the effects of artery curvature and endograft oversizing, the selection of an endograft with a larger diameter than the artery, on endoleak creation. Finite element analysis is employed to simulate the deployment of endografts in arteries with varying curvature and diameter. Numerical simulations are conducted to assess the seal zone and to quantify the potential endoleak volume as a function of curvature and oversizing. A theoretical framework is developed to explain the mechanisms of endoleak formation along with proof-of-concept experiments. Two main mechanisms of endoleak creation are identified: local buckling due to diameter mismatch and global buckling due to centerline curvature mismatch. Local buckling, characterized by excess graft material buckling and wrinkle formation, increases with higher levels of oversizing, leading to a larger potential endoleak volume. Global buckling, where the endograft bends or deforms to conform to the centerline curvature of the artery, is observed to require a certain degree of oversizing to bridge the curvature mismatch. This study highlights the importance of considering both curvature and diameter mismatch in the design and clinical use of endografts. Understanding the mechanisms of endoleak formation can provide valuable insights for optimizing endograft design and surgical planning, leading to improved clinical outcomes in endovascular aortic procedures.
Collapse
Affiliation(s)
- Žiga Donik
- Faculty of Mechanical Engineering, University of Maribor, Smetanova ulica 17, 2000 Maribor, Slovenia.
| | - Willa Li
- Section of Vascular Surgery and Endovascular Therapy, Department of Surgery, The University of Chicago, 5841 S Maryland Ave, MC 5028, Chicago, IL 60637, USA
| | - Blessing Nnate
- Section of Vascular Surgery and Endovascular Therapy, Department of Surgery, The University of Chicago, 5841 S Maryland Ave, MC 5028, Chicago, IL 60637, USA
| | - Joseph A Pugar
- Section of Vascular Surgery and Endovascular Therapy, Department of Surgery, The University of Chicago, 5841 S Maryland Ave, MC 5028, Chicago, IL 60637, USA
| | - Nhung Nguyen
- Section of Vascular Surgery and Endovascular Therapy, Department of Surgery, The University of Chicago, 5841 S Maryland Ave, MC 5028, Chicago, IL 60637, USA
| | - Ross Milner
- Section of Vascular Surgery and Endovascular Therapy, Department of Surgery, The University of Chicago, 5841 S Maryland Ave, MC 5028, Chicago, IL 60637, USA
| | - Enrique Cerda
- Departamento de Física, Facultad de Ciencia, Universidad de Santiago de Chile (USACH), Santiago Chile
| | - Luka Pocivavsek
- Section of Vascular Surgery and Endovascular Therapy, Department of Surgery, The University of Chicago, 5841 S Maryland Ave, MC 5028, Chicago, IL 60637, USA.
| | - Janez Kramberger
- Faculty of Mechanical Engineering, University of Maribor, Smetanova ulica 17, 2000 Maribor, Slovenia
| |
Collapse
|
2
|
Shahbazian N, Romero DA, Forbes TL, Amon CH. Prediction of bird-beak configuration in thoracic endovascular aortic repair preoperatively using patient-specific finite element simulations. JVS Vasc Sci 2023; 4:100108. [PMID: 37519336 PMCID: PMC10372321 DOI: 10.1016/j.jvssci.2023.100108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 04/03/2023] [Indexed: 08/01/2023] Open
Abstract
Objectives Formation of bird-beak configuration in thoracic endovascular aortic repair (TEVAR) has been shown to be correlated with the risk of complications such as type Ia endoleaks, stent graft migration, and collapse. The aim of this study was to use patient-specific computational simulations of TEVAR to predict the formation of bird-beak configuration preoperatively. Methods Patient-specific TEVAR computational simulations are developed using a retrospective cohort of patients treated for thoracic aortic aneurysm. The preoperative computed tomography images were segmented to develop three-dimensional geometry of the thoracic aorta. These geometries were used in finite element simulations of stent graft deployment during TEVAR. Simulated results were compared against the postoperative computed tomography images to assess the accuracy of simulations in predicting the proximal position of a deployed stent graft and presence of bird-beak. In cases with a bird-beak configuration, the length and angle of the bird-beak were measured and compared between the simulated and postoperative results. Results Twelve TEVAR patient cases were simulated. Computational simulations were able to accurately predict whether the proximal stent graft was fully apposed, proximal bare stents were protruded, or bird-beak configuration was present. In three cases with bird-beak configuration, simulations predicted the length and angle of the bird-beak with less than 10% and 24% error, respectively. Other factors such as a small aortic arch angle, small oversizing value, and landing zones close to the arch apex may have played a role in formation of bird-beak in these patients. Conclusions Computational simulations of TEVAR accurately predicted the proximal position of a deployed stent graft and the presence of bird-beak preoperatively. The computational models were able to predict the length and angle of bird-beak configurations with good accuracy. These simulations can provide insight into the surgical planning process with the goal of minimizing bird-beak occurrence.
Collapse
Affiliation(s)
- Negin Shahbazian
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada
| | - David A. Romero
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada
| | - Thomas L. Forbes
- Division of Vascular Surgery, Department of Surgery, Peter Munk Cardiac Centre, University Health Network, University of Toronto, Toronto, ON, Canada
| | - Cristina H. Amon
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada
- Department of Mechanical and Industrial Engineering, Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| |
Collapse
|
3
|
Identification of geometric and mechanical factors predictive of bird-beak configuration in thoracic endovascular aortic repair using computational models of stent graft deployment. JVS Vasc Sci 2022; 3:259-273. [PMID: 35938091 PMCID: PMC9352945 DOI: 10.1016/j.jvssci.2022.05.056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 05/25/2022] [Indexed: 11/21/2022] Open
|
4
|
Cao L, Ge Y, He Y, Wang X, Rong D, Lu W, Liu X, Guo W. Association between aortic arch angulation and bird-beak configuration after thoracic aortic stent graft repair of type B aortic dissection. Interact Cardiovasc Thorac Surg 2021; 31:688-696. [PMID: 33025008 DOI: 10.1093/icvts/ivaa171] [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: 04/03/2020] [Revised: 07/06/2020] [Accepted: 07/15/2020] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVES The goal of this study was to investigate factors favouring the bird-beak configuration after thoracic endovascular aortic repair (TEVAR) for type B aortic dissection. METHODS We retrospectively analysed 76 patients with type B aortic dissection who underwent landing zone 1 and 2 TEVAR from December 2015 to January 2018. Preoperative aortic arch geometry (aortic arch length, maximal diameter and angulation), stent graft details and operative details were evaluated. A bird-beak configuration was defined as a ≥5-mm gap between the proximal end of the stent and the aortic wall of the lesser curvature. RESULTS Patients were stratified into those with (n = 46) and without (n = 30) a bird-beak configuration. The baseline demographics, dissection chronicity, clinical features and implanted devices were largely similar between the 2 groups. No significant difference was observed in the arch length or maximal arch diameter. However, the mean aortic arch angulation was greater in patients with than without a bird-beak configuration (61.4° vs 51.3°; P < 0.001). No influence of either the stent graft brand or the proximal stent graft type was observed. The multivariable analysis showed that the aortic arch angulation was an independent risk factor for a bird-beak configuration (odds ratio 1.15, 95% confidence interval 1.07-1.24; P < 0.001). A cut-off angle of 59.15° was predictive of a bird-beak configuration (sensitivity 59%; specificity 77%). CONCLUSIONS The preoperative aortic arch angulation was an independent predictor of a postoperative bird-beak configuration in patients with type B aortic dissection who underwent TEVAR that involved the aortic arch. An angle of >59.15° may imply a relatively hostile anatomy with a higher risk of a bird-beak configuration.
Collapse
Affiliation(s)
- Long Cao
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China.,Department of General Surgery, Chinese PLA No. 983 Hospital, Tianjin, China
| | - Yangyang Ge
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China
| | - Yuan He
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China
| | - Xinhao Wang
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China
| | - Dan Rong
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China
| | - Weihang Lu
- Department of General Surgery, The Sixth Medical Center of Chinese, PLA General Hospital, Beijing, China
| | - Xiaoping Liu
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China
| | - Wei Guo
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China
| |
Collapse
|
5
|
Bondesson J, Suh GY, Marks N, Dake MD, Lee JT, Cheng CP. Influence of thoracic endovascular aortic repair on true lumen helical morphology for Stanford type B dissections. J Vasc Surg 2021; 74:1499-1507.e1. [PMID: 33940073 DOI: 10.1016/j.jvs.2021.04.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 04/19/2021] [Indexed: 10/21/2022]
Abstract
OBJECTIVE Thoracic endovascular aortic repair (TEVAR) can change the morphology of the flow lumen in aortic dissections, which may affect aortic hemodynamics and function. This study characterizes how the helical morphology of the true lumen in type B aortic dissections is altered by TEVAR. METHODS Patients with type B aortic dissection who underwent computed tomography angiography before and after TEVAR were retrospectively reviewed. Images were used to construct three-dimensional stereolithographic surface models of the true lumen and whole aorta using custom software. Stereolithographic models were segmented and co-registered to determine helical morphology of the true lumen with respect to the whole aorta. The true lumen region covered by the endograft was defined based on fiducial markers before and after TEVAR. The helical angle, average helical twist, peak helical twist, and cross-sectional eccentricity, area, and circumference were quantified in this region for pre- and post-TEVAR geometries. RESULTS Sixteen patients (61.3 ± 8.0 years; 12.5% female) were treated successfully for type B dissection (5 acute and 11 chronic) with TEVAR and scans before and after TEVAR were retrospectively obtained (follow-up interval 52 ± 91 days). From before to after TEVAR, the true lumen helical angle (-70.0 ± 71.1 to -64.9 ± 75.4°; P = .782), average helical twist (-4.1 ± 4.0 to -3.7 ± 3.8°/cm; P = .674), and peak helical twist (-13.2 ± 15.2 to -15.4 ± 14.2°/cm; P = .629) did not change. However, the true lumen helical radius (1.4 ± 0.5 to 1.0 ± 0.6 cm; P < .05) and eccentricity (0.9 ± 0.1 to 0.7 ± 0.1; P < .05) decreased, and the cross-sectional area (3.0 ± 1.1 to 5.0 ± 2.0 cm2; P < .05) and circumference (7.1 ± 1.0 to 8.0 ± 1.4 cm; P < .05) increased significantly from before to after TEVAR. The distinct bimodal distribution of chiral and achiral native dissections disappeared after TEVAR, and subgroup analyses showed that the true lumen circumference of acute dissections increased with TEVAR, although it did not for chronic dissections. CONCLUSIONS The unchanged helical angle and average and peak helical twists as a result of TEVAR suggest that the angular positions of the true lumen are constrained and that the endografts were helically conformable in the angular direction. The decrease of helical radius indicated a straightening of the corkscrew shape of the true lumen, and in combination with more circular and expanded lumen cross-sections, TEVAR produced luminal morphology that theoretically allows for lower flow resistance through the endografted portion. The impact of TEVAR on dissection flow lumen morphology and the interaction between endografts and aortic tissue can provide insight for improving device design, implantation technique, and long-term clinical outcomes.
Collapse
Affiliation(s)
- Johan Bondesson
- Division of Dynamics, Chalmers University of Technology, Gothenburg, Sweden.
| | - Ga-Young Suh
- Department of Biomedical Engineering, California State University, Long Beach, Calif; Division of Vascular Surgery, Stanford University, Stanford, Calif
| | - Neil Marks
- Division of Vascular Surgery, Stanford University, Stanford, Calif
| | - Michael D Dake
- Department of Surgery, University of Arizona, Tucson, Ariz
| | - Jason T Lee
- Division of Vascular Surgery, Stanford University, Stanford, Calif
| | | |
Collapse
|
6
|
Suh GY, Bondesson J, Zhu YD, Lee JT, Dake MD, Cheng CP. Multiaxial pulsatile dynamics of the thoracic aorta and impact of thoracic endovascular repair. Eur J Radiol Open 2021; 8:100333. [PMID: 33748348 PMCID: PMC7957153 DOI: 10.1016/j.ejro.2021.100333] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/22/2021] [Accepted: 02/24/2021] [Indexed: 11/17/2022] Open
Abstract
Altered motion of the thoracic aorta after thoracic endovascular aortic repair. Geometric analysis with cardiac-gated computed tomography and computer modeling. Decreased motion of the stented aorta and increased motion above the stented aorta. Longitudinal curvature and diametric deformation affected by presence of endograft.
Purpose The thoracic aorta is a highly mobile organ whose dynamics are altered by thoracic endovascular aorta repair (TEVAR). The aim of this study was to quantify cardiac pulsatility-induced multi-axial deformation of the thoracic aorta before and after descending aortic TEVAR. Methods Eleven TEVAR patients (8 males and 3 females, age 57–89) underwent retrospective cardiac-gated CT angiography before and after TEVAR. 3D geometric models of the thoracic aorta were constructed, and lumen centerlines, inner and outer surface curves, and cross-sections were extracted to measure aortic arclength, centerline, inner surface, and outer surface longitudinal curvatures, as well as cross-sectional effective diameter and eccentricity for the ascending and stented aortic portions. Results From pre- to post-TEVAR, arclength deformation was increased at the ascending aorta from 5.9 ± 3.1 % to 8.8 ± 4.4 % (P < 0.05), and decreased at the stented aorta from 7.5 ± 5.1 % to 2.7 ± 2.5 % (P < 0.05). Longitudinal curvature and diametric deformations were reduced at the stented aorta. Centerline curvature, inner surface curvature, and cross-sectional eccentricity deformations were increased at the distal ascending aorta. Conclusions Deformations were reduced in the stented thoracic aorta after TEVAR, but increased in the ascending aorta near the aortic arch, possibly as a compensatory mechanism to maintain overall thoracic compliance in the presence of reduced deformation in the stiffened stented aorta.
Collapse
Affiliation(s)
- Ga-Young Suh
- Department of Biomedical Engineering, California State University, Long Beach: 1250 Bellflower Blvd, Long Beach, CA, 90840, USA.,Department of Vascular Surgery, Stanford University, 300 Pasteur Drive, Stanford, CA, 94305, USA
| | - Johan Bondesson
- Division of Dynamics, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
| | - Yufei D Zhu
- Department of Vascular Surgery, Stanford University, 300 Pasteur Drive, Stanford, CA, 94305, USA
| | - Jason T Lee
- Department of Vascular Surgery, Stanford University, 300 Pasteur Drive, Stanford, CA, 94305, USA
| | - Michael D Dake
- Department of Cardiothoracic Surgery, Stanford University, 300 Pasteur Drive, Stanford, CA, 94305, USA
| | - Christopher P Cheng
- Department of Vascular Surgery, Stanford University, 300 Pasteur Drive, Stanford, CA, 94305, USA
| |
Collapse
|
7
|
Midulla M, Moreno R, Negre-Salvayre A, Beregi JP, Haulon S, Loffroy R, Dake M, Rousseau H. Impact of Thoracic Endografting on the Hemodynamics of the Native Aorta: Pre- and Postoperative Assessments of Wall Shear Stress and Vorticity Using Computational Fluid Dynamics. J Endovasc Ther 2020; 28:63-69. [PMID: 33025866 DOI: 10.1177/1526602820959662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE To quantify the hemodynamic consequences of thoracic endovascular aortic repair (TEVAR) by comparing the preoperative and postoperative wall shear stress (WSS) and vorticity profiles on computational fluid dynamics (CFD) simulations. MATERIALS AND METHODS The pre- and postoperative computed tomography (CT) scans from 20 consecutive patients (median age 69 years, range 20-87) treated for different thoracic aortic pathologies (11 aneurysms, 5 false aneurysms, 3 penetrating ulcers, and 1 traumatic aortic rupture) were segmented to construct patient-specific CFD models using a meshless code. The simulations were run over the cardiac cycle, and the WSS and vorticity values measured at the proximal and distal landing zones were compared. RESULTS The CFD runs provided 4-dimensional simulations of blood flow in all patients. WSS and vorticity profiles at the proximal landing zone (located in zones 0-3 in 15 patients) varied in 18 and 20 of the cases, respectively; WSS was increased in 11 cases and the vorticity in 9. Pre- and postoperative WSS median values were 4.19 and 4.90 Pa, respectively. Vorticity median values were 40.38 and 39.17 Hz, respectively. CONCLUSION TEVAR induces functional alterations in the native thoracic aorta, though the prognostic significance of these changes is still unknown. CFD appears to be a valuable tool to explore aortic hemodynamics, and its application in a larger series would help define a predictive role for these hemodynamic assessments.
Collapse
Affiliation(s)
- Marco Midulla
- Department of Diagnostic and Therapeutic Radiology, Center for Mini-Invasive Image-Guided Therapies, Centre Hospitalier Universitaire de Dijon, Université de Bourgogne Franche-Comté, Dijon, France
| | | | | | | | - Stéphan Haulon
- Aortic Center, Hopital Marie-Lannelongue, Groupe Hospitalier Paris Saint Joseph, Paris, France
| | - Romaric Loffroy
- Department of Diagnostic and Therapeutic Radiology, Center for Mini-Invasive Image-Guided Therapies, Centre Hospitalier Universitaire de Dijon, Université de Bourgogne Franche-Comté, Dijon, France
| | - Michael Dake
- Health Sciences, University of Arizona, Tucson, AZ, USA
| | - Hervé Rousseau
- INSERM, UMR 1048, I2MC, Toulouse, France.,Department of Radiology, CHU Rangueil, Nîmes, France
| |
Collapse
|
8
|
Tran K, Li M, Stern JR, Lee JT. Thoracic Aortic Dilation after Endovascular Repair of Blunt Traumatic Aortic Injury. Ann Vasc Surg 2020; 70:101-108. [PMID: 32603842 DOI: 10.1016/j.avsg.2020.06.049] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 05/06/2020] [Accepted: 06/24/2020] [Indexed: 11/16/2022]
Abstract
BACKGROUND Thoracic endovascular aneurysm repair (TEVAR) has become the current standard of care for emergent treatment of traumatic blunt thoracic aortic injuries (BTAI). Although aortic dilation (AD) of the infrarenal neck after EVAR for aortic aneurysms has been studied, changes in aortic diameter after TEVAR for BTAI is not well understood. This study aims to characterize changes in thoracic aortic diameter after stent-graft placement in the setting of nonaneurysmal traumatic aortic injury. METHODS A single-center, retrospective review was performed involving patients presenting with BTAI treated with TEVAR. Only patients with at least 12 months follow-up were included. Aortic diameter, defined as the outer-to-outer diameter on 3D center-line imaging, was measured at six locations along the proximal and mid thoracic aorta. The first postoperative CT (≤1 month) served as a baseline from which interval measurements were compared. RESULTS Twenty patients with BTAI treated from 2011 to 2017 had adequate imaging available for review and were included in this study cohort. Median follow-up time was 46.8 (12-80, range) months. At the latest follow-up, AD occurred at all measured locations within the endograft, starting from the proximal graft edge (0.62 ± 0.69 mm, P = 0.027) to the distal graft edge (1.21 ± 1.28 mm, P = 0.003). AD was most pronounced in the distal graft segment 2 cm proximal to the distal graft edge, with a mean AD of 1.32 ± 1.59 mm (+5.3%, P < 0.001). At this location, AD was found to increase in a linear manner with an estimated rate of 0.67 ± 0.20 mm/year (P = 0.006). The native aorta proximal and distal to the endograft was not found to significantly dilate during follow-up (P = 0.280-0.897). Seventy percent of the patients were found to have AD >5%. The amount of AD was not found to be associated with either graft oversizing (P = 0.151) or age (P = 0.340). There were no cases of graft migration, erosion, or endoleak. CONCLUSIONS AD is a common benign finding after TEVAR for BTAI. AD is most pronounced at the near the distal end of the stent graft. In late-term follow-up, there are no known associated complications related to AD.
Collapse
Affiliation(s)
- Kenneth Tran
- Division of Vascular Surgery, Stanford University, Stanford, CA.
| | - Ming Li
- Division of Vascular Surgery, Stanford University, Stanford, CA
| | - Jordan R Stern
- Division of Vascular Surgery, Stanford University, Stanford, CA
| | - Jason T Lee
- Division of Vascular Surgery, Stanford University, Stanford, CA
| |
Collapse
|