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Keramati H, Birgersson E, Kim S, Leo HL. A Monte Carlo Sensitivity Analysis for a Dimensionally Reduced-Order Model of the Aortic Dissection. Cardiovasc Eng Technol 2024; 15:333-345. [PMID: 38381368 DOI: 10.1007/s13239-024-00718-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 01/11/2024] [Indexed: 02/22/2024]
Abstract
PURPOSE Aortic dissection is associated with a high mortality rate. Although computational approaches have shed light on many aspects of the disease, a sensitivity analysis is required to determine the significance of different factors. Because of its complex geometry and high computational expense, the three-dimensional (3D) fluid-structure interaction (FSI) simulation is not a suitable approach for sensitivity analysis. METHODS We performed a Monte Carlo simulation (MCS) to investigate the sensitivity of hemodynamic quantities to the lumped parameters of our zero-dimensional (0D) model with numerically calculated lumped parameters. We performed local and global analyses on the effect of the model parameters on important hemodynamic quantities. RESULTS The MCS showed that a larger lumped resistance value for the false lumen and the tears result in a higher retrograde flow rate in the false lumen (the coefficient of variation,c v , i = 0.0183 , the sensitivityS X i σ = 0.54 , Spearman's coefficient,ρ s = 0.464 ). For the intraluminal pressure, our results show a significant role in the resistance and inertance of the true lumen (the coefficient of variation,c v , i = 0.0640 , the sensitivityS X i σ = 0.85 , and Spearman's coefficient,ρ s = 0.855 for the inertance of the true lumen). CONCLUSION This study highlights the necessity of comparing the results of the local and global sensitivity analyses to understand the significance of multiple lumped parameters. Because of the efficiency of the method, our approach is potentially useful to investigate and analyze medical planning.
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Affiliation(s)
- Hamed Keramati
- Integrative Sciences and Engineering Programme (ISEP), National University of Singapore, Singapore, Singapore
- Department of Biomedical Engineering, National University of Singapore, Singapore, 117576, Singapore
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - Erik Birgersson
- Department of Mechanical Engineering, National University of Singapore, Singapore, 117575, Singapore
| | - Sangho Kim
- Integrative Sciences and Engineering Programme (ISEP), National University of Singapore, Singapore, Singapore
- Department of Biomedical Engineering, National University of Singapore, Singapore, 117576, Singapore
| | - Hwa Liang Leo
- Integrative Sciences and Engineering Programme (ISEP), National University of Singapore, Singapore, Singapore.
- Department of Biomedical Engineering, National University of Singapore, Singapore, 117576, Singapore.
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Tanaka T, Yamamura O, Onishi H, Ikawa M, Hayashi H, Hamano T. Ten-year follow up of incidental spontaneous extracranial internal carotid artery dissection in a Japanese asymptomatic older man: A case report. Sci Prog 2023; 106:368504231214119. [PMID: 38105490 PMCID: PMC10729627 DOI: 10.1177/00368504231214119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
This report presents a unique finding of an incidental right internal carotid artery dissection in an asymptomatic 69-year-old man. The report highlights the possible trigger and long-term outcomes of this condition. The patient had participated in Japanese archery competitions for many years. His medical history included hypertension and a prior ischemic stroke in the left lateral medulla, resulting in Wallenberg syndrome. During a routine visit, head magnetic resonance angiography revealed right internal carotid artery dissection. He was managed conservatively with antiplatelet therapy and close monitoring. Follow-up imaging after 10 years showed no changes, and the patient remained asymptomatic. Therefore, routine screening for incidental findings is important even in asymptomatic patients. Archery competitions may be a possible trigger for internal carotid artery dissection. The presence of re-entry in the lesion at the time of onset can be a predictor of a good long-term prognosis.
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Affiliation(s)
- Tokuharu Tanaka
- Department of Family and Emergency Medicine, University of Fukui Hospital, Fukui, Japan
| | - Osamu Yamamura
- Regional Medicine Promotion Course, Faculty of Medical Sciences, University of Fukui, Fukui, Japan
- Department of Neurology, University of Fukui Hospital, Fukui, Japan
| | - Hidenori Onishi
- Regional Medicine Promotion Course, Faculty of Medical Sciences, University of Fukui, Fukui, Japan
| | - Masamichi Ikawa
- Department of Neurology, University of Fukui Hospital, Fukui, Japan
| | - Hiroyuki Hayashi
- Department of Family and Emergency Medicine, University of Fukui Hospital, Fukui, Japan
| | - Tadanori Hamano
- Department of Neurology, University of Fukui Hospital, Fukui, Japan
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Li D, Wang J, Zeng W, Zeng X, Liu Z, Cao H, Yuan D, Zheng T. The loss of helical flow in the thoracic aorta might be an identifying marker for the risk of acute type B aortic dissection. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2023; 230:107331. [PMID: 36621070 DOI: 10.1016/j.cmpb.2022.107331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 12/06/2022] [Accepted: 12/29/2022] [Indexed: 06/17/2023]
Abstract
BACKGROUND AND OBJECTIVE The occurrence of acute type B aortic dissection (TBAD) remained unclear. This study aimed to investigate the association between flow features and hemodynamic parameters in aortas that demonstrated the risk of TBAD occurrence. METHODS The geometries of 15 hyperacute TBAD and 12 control patients (with healthy aorta) were reconstructed from computed tomography angiography images. Pre-TBAD models were then obtained by eliminating the dissection flaps. Flow features and hemodynamic parameters, including wall shear stress-related parameters and helicities, were compared between pre-TBAD and control models using computational fluid dynamics. RESULTS There were no significant differences in baseline characteristics and anatomical parameters between the two groups. Significant contralateral helical blood flow was present in the healthy thoracic aorta, while almost no helical flow was observed in the pre-TBAD group. In addition, the mean normal transverse wall shear stress (NtransWSS) was significantly higher in the pre-TBAD group (aortic arch 0.49±0.09 vs. 0.40±0.05, P = 0.04; descending aorta: 0.46±0.05 vs. 0.33±0.02, P<0.01). Moreover, a significantly negative correlation was found between helicity and NtransWSS in the descending aorta. Moreover, the location of primary tears in 12 pre-TABD subjects matched well with regions of high NtransWSS. CONCLUSIONS Loss of helical flow in the aortic arch and descending aorta may be a major flow feature in patients with underlying TBAD, resulting in increased flow disturbance and wall lesions.
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Affiliation(s)
- Da Li
- Department of Applied Mechanics, Sichuan University, No.24 South Section 1, Chengdu 610065, China; Yibin Institute of Industrial Technology, Sichuan University Yibin Park, Yibin, China
| | - Jiarong Wang
- Division of Vascular Surgery, Department of General Surgery, West China Hospital, Sichuan University, No. 37 Guo Xue Xiang, Chengdu 610041, China
| | - Wen Zeng
- Division of radiology, West China Hospital, Sichuan University, Chengdu, China
| | - Xiangguo Zeng
- Department of Applied Mechanics, Sichuan University, No.24 South Section 1, Chengdu 610065, China
| | - Zhan Liu
- Department of Applied Mechanics, Sichuan University, No.24 South Section 1, Chengdu 610065, China; Yibin Institute of Industrial Technology, Sichuan University Yibin Park, Yibin, China
| | - Haoyao Cao
- Department of Applied Mechanics, Sichuan University, No.24 South Section 1, Chengdu 610065, China; Yibin Institute of Industrial Technology, Sichuan University Yibin Park, Yibin, China
| | - Ding Yuan
- Division of Vascular Surgery, Department of General Surgery, West China Hospital, Sichuan University, No. 37 Guo Xue Xiang, Chengdu 610041, China; Med-X center for informatics, Sichuan University, Chengdu, China.
| | - Tinghui Zheng
- Department of Applied Mechanics, Sichuan University, No.24 South Section 1, Chengdu 610065, China; Yibin Institute of Industrial Technology, Sichuan University Yibin Park, Yibin, China; Med-X center for informatics, Sichuan University, Chengdu, China.
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Jafarinia A, Melito GM, Müller TS, Rolf-Pissarczyk M, Holzapfel GA, Brenn G, Ellermann K, Hochrainer T. Morphological parameters affecting false lumen thrombosis following type B aortic dissection: a systematic study based on simulations of idealized models. Biomech Model Mechanobiol 2023; 22:885-904. [PMID: 36630014 PMCID: PMC10167197 DOI: 10.1007/s10237-023-01687-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 01/02/2023] [Indexed: 01/12/2023]
Abstract
Type B aortic dissection (TBAD) carries a high risk of complications, particularly with a partially thrombosed or patent false lumen (FL). Therefore, uncovering the risk factors leading to FL thrombosis is crucial to identify high-risk patients. Although studies have shown that morphological parameters of the dissected aorta are related to FL thrombosis, often conflicting results have been reported. We show that recent models of thrombus evolution in combination with sensitivity analysis methods can provide valuable insights into how combinations of morphological parameters affect the prospect of FL thrombosis. Based on clinical data, an idealized geometry of a TBAD is generated and parameterized. After implementing the thrombus model in computational fluid dynamics simulations, a global sensitivity analysis for selected morphological parameters is performed. We then introduce dimensionless morphological parameters to scale the results to individual patients. The sensitivity analysis demonstrates that the most sensitive parameters influencing FL thrombosis are the FL diameter and the size and location of intimal tears. A higher risk of partial thrombosis is observed when the FL diameter is larger than the true lumen diameter. Reducing the ratio of the distal to proximal tear size increases the risk of FL patency. In summary, these parameters play a dominant role in classifying morphologies into patent, partially thrombosed, and fully thrombosed FL. In this study, we point out the predictive role of morphological parameters for FL thrombosis in TBAD and show that the results are in good agreement with available clinical studies.
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Affiliation(s)
- Alireza Jafarinia
- Institute of Strength of Materials, Graz University of Technology, Graz, Austria.
| | - Gian Marco Melito
- Institute of Mechanics, Graz University of Technology, Graz, Austria.
| | - Thomas Stephan Müller
- Institute of Fluid Mechanics and Heat Transfer, Graz University of Technology, Graz, Austria
| | | | - Gerhard A Holzapfel
- Institute of Biomechanics, Graz University of Technology, Graz, Austria.,Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Günter Brenn
- Institute of Fluid Mechanics and Heat Transfer, Graz University of Technology, Graz, Austria
| | - Katrin Ellermann
- Institute of Mechanics, Graz University of Technology, Graz, Austria
| | - Thomas Hochrainer
- Institute of Strength of Materials, Graz University of Technology, Graz, Austria
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Okumura T, Hattori K, Hatano H, Fujitani S, Wada K, Sato Y, Wakabayashi M. Successful carotid artery stenting with a double-layer micromesh stent for spontaneous extracranial internal carotid artery dissection: a case report. NAGOYA JOURNAL OF MEDICAL SCIENCE 2022; 84:462-469. [PMID: 35967942 PMCID: PMC9350565 DOI: 10.18999/nagjms.84.2.462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 08/18/2021] [Indexed: 11/23/2022]
Abstract
Extracranial internal carotid artery dissection is a relatively rare disease in Japan. We herein report a case of a 60-year-old woman with spontaneous left internal carotid artery dissection with a dilated and dissected cavity. Following the identification and measurement of the true and false lumens using intravascular ultrasound, a double-layer micromesh stent (Casper stent; Microvention, Terumo, Tustin, CA, USA) was deployed for post-dilation. No perioperative complications were observed, and the patient was discharged on postoperative day 6.
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Affiliation(s)
- Taro Okumura
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Nagoya, Japan
,Department of Neurosurgery, Japanese Red Cross Aichi Medical Center Nagoya Daiichi Hospital, Nagoya, Japan
| | - Kenichi Hattori
- Department of Neurosurgery, Japanese Red Cross Aichi Medical Center Nagoya Daiichi Hospital, Nagoya, Japan
| | - Hisashi Hatano
- Department of Neurosurgery, Japanese Red Cross Aichi Medical Center Nagoya Daiichi Hospital, Nagoya, Japan
| | - Shigeru Fujitani
- Department of Neurosurgery, Japanese Red Cross Aichi Medical Center Nagoya Daiichi Hospital, Nagoya, Japan
| | - Kentaro Wada
- Department of Neurosurgery, Japanese Red Cross Aichi Medical Center Nagoya Daiichi Hospital, Nagoya, Japan
| | - Yoshiki Sato
- Department of Neurosurgery, Japanese Red Cross Aichi Medical Center Nagoya Daiichi Hospital, Nagoya, Japan
| | - Masahiro Wakabayashi
- Department of Neurosurgery, Japanese Red Cross Aichi Medical Center Nagoya Daiichi Hospital, Nagoya, Japan
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Li Z, Xu H, Armour CH, Guo Y, Xiong J, Xu X, Chen D. The Necessity to Seal the Re-Entry Tears of Aortic Dissection After TEVAR: A Hemodynamic Indicator. Front Bioeng Biotechnol 2022; 10:831903. [PMID: 35433660 PMCID: PMC9009393 DOI: 10.3389/fbioe.2022.831903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 01/11/2022] [Indexed: 11/13/2022] Open
Abstract
Thoracic endovascular aortic repair (TEVAR) is a common treatment for Stanford type B aortic dissection (TBAD). However, re-entry tears might be found distal to the stented region which transports blood between the true and false lumens. Sealing the re-entry tears, especially for the thoracic tears, could further reduce blood perfusion to the false lumen; however, it might also bring risks by re-intervention or surgery. Wise determination of the necessity to seal the re-entry tears is needed. In this study, patient-specific models of TBAD were reconstructed, and the modified models were established by virtually excluding the thoracic re-entries. Computational hemodynamics was investigated, and the variation of the functional index and first balance position (FBP) of the luminal pressure difference, due to the sealing of the re-entries, was reported. The results showed that the direction of the net flow through the unstented thoracic re-entries varied among cases. Excluding the re-entries with the net flow toward the false lumen may induce the FBP moving distally and the relative particle residence time increasing in the false lumen. This study preliminarily demonstrated that the hemodynamic status of the re-entry tears might serve as an indicator to the necessity of sealing. By quantifying the through-tear flow exchange and shift of FBP, one can predict the hemodynamic benefit by sealing the thoracic re-entries and thus wisely determine the necessity of further interventional management.
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Affiliation(s)
- Zhenfeng Li
- School of Life Science, Beijing Institute of Technology, Beijing, China
- Wenzhou Safety (Emergency) Institute of Tianjin University, Zhejiang, China
| | - Huanming Xu
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Chlöe Harriet Armour
- Department of Chemical Engineering, Imperial College London, London, United Kingdom
| | - Yuze Guo
- School of Biomedical Engineering, University of Sydney, Sydney, NSW, Australia
| | - Jiang Xiong
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China
- *Correspondence: Jiang Xiong, ; Xiaoyun Xu,
| | - Xiaoyun Xu
- Department of Chemical Engineering, Imperial College London, London, United Kingdom
- *Correspondence: Jiang Xiong, ; Xiaoyun Xu,
| | - Duanduan Chen
- School of Life Science, Beijing Institute of Technology, Beijing, China
- Wenzhou Safety (Emergency) Institute of Tianjin University, Zhejiang, China
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7
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Wang R, Kan Y, Yang M, Zhang H, Zhang X, Dai X, Zhai S, Hu H, Zhang X, Chen B, Huang J, Qin X, Xiao Z, Lu X, Guo W, Si Y, Fu W. Clinical Results and Aortic Remodeling After Endovascular Treatment for Complicated Type B Aortic Dissection With the “Fabulous” Stent System. Front Cardiovasc Med 2022; 9:817675. [PMID: 35237674 PMCID: PMC8882966 DOI: 10.3389/fcvm.2022.817675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 01/14/2022] [Indexed: 12/03/2022] Open
Abstract
Objective To report the clinical outcomes and aortic remodeling after the implantation of a self-developed, biomechanically optimized, two-stage thoracic stent system named Fabulous. Background Given the efficacy of the PETTICOAT concept, the benefits of Fabulous and the behavior of remodeling in different segments need further investigation. Methods This is a prospective and multicenter study. From 2017 to 2019, 145 patients (mean age, 56.6 years; 88.3% male) from 14 centers were included in this cohort. The clinical results and core laboratory results were from a central electronic data capture system. Computed tomographic angiography was performed preoperatively, 1 month, 6 months and yearly thereafter and was used for volumetric analysis by 3mensio (Bilthoven, The Netherlands). After the 1-year follow-up, 97.2 and 87.6% of the clinical and imaging results of the eligible patients were available. Results Both stent grafts and bare stents were successfully delivered in place in 100% of the patients. The 30-day mortality and 1-year freedom from all-cause mortality were 2.1 and 96.6%, respectively. The incidence of entry flow was 11.7% at 30 days and 6.2% at 365 days. No cases of stent-induced new entry (SINE) or reintervention were observed. After the 1-year follow-up, the true lumen/overall volume ratio reached 88%. The following subdivided segment volume changes were recorded: stent graft segment TL +56%; FL −92%, bare stent segment TL +32%; FL −75%, and there were no significant changes in the visceral segment. Conclusions These outcomes indicated that there were favorable clinical benefits of Fabulous stent system. This device achieved a low short-term mortality and a low incidence of reintervention. In addition, patients undergoing Fabulous stent system implantation showed remodeling both on descending aorta and on the distal aorta. The volume changes in the TL and FL varied in the different segments. The long-term follow-up is still ongoing.
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Affiliation(s)
- Ruihan Wang
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yuanqing Kan
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Mou Yang
- Vascular Surgery, Yantai Yuhuangding Hospital Affiliated With Qingdao University, Yantai, China
| | - Hongkun Zhang
- Department of Vascular Surgery, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Xiaoming Zhang
- Department of Vascular Surgery, Peking University People's Hospital, Beijing, China
| | - Xiangchen Dai
- Department of General Surgery, Tianjin Medical University General Hospital, Tianjin, China
| | - Shuiting Zhai
- Department of Vascular and Endovascular Surgery, Henan Provincial People's Hospital, Zhengzhou University, Zhengzhou, China
| | - Hejie Hu
- Department of Vascular Surgery, The First Affiliated Hospital of USTC, Hefei, China
| | - Xiwei Zhang
- Department of Vascular Surgery, Jiangsu Province Hospital, Nanjing, China
| | - Bing Chen
- Department of Vascular Surgery, School of Medicine, Second Affiliated Hospital, Zhejiang University, Hangzhou, China
| | - Jianhua Huang
- Department of General and Vascular Surgery, Xiangya Hospital, Central South University, Changsha, China
| | - Xiao Qin
- Department of Vascular Surgery, The First Affiliated Hospital of Guangxi Medical University, Guangxi, China
| | - Zhanxiang Xiao
- Department of General Surgery, Hainan Province People's Hospital, Haikou, China
| | - Xinwu Lu
- Department of Vascular Surgery, Shanghai Ninth People's Hospital, Shanghai, China
| | - Wei Guo
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China
| | - Yi Si
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
- *Correspondence: Yi Si
| | - Weiguo Fu
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
- Weiguo Fu
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Hu H, Liu Z, Chen G, Yuan D, Zheng T. Analysis of aortic wall stress and morphology in patients with type B aortic dissection. MEDICINE IN NOVEL TECHNOLOGY AND DEVICES 2021. [DOI: 10.1016/j.medntd.2021.100081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Zilber ZA, Boddu A, Malaisrie SC, Hoel AW, Mehta CK, Vassallo P, Burris NS, Roldán-Alzate A, Collins JD, François CJ, Allen BD. Noninvasive Morphologic and Hemodynamic Evaluation of Type B Aortic Dissection: State of the Art and Future Perspectives. Radiol Cardiothorac Imaging 2021; 3:e200456. [PMID: 34235440 DOI: 10.1148/ryct.2021200456] [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: 08/01/2020] [Revised: 05/04/2021] [Accepted: 05/05/2021] [Indexed: 12/21/2022]
Abstract
Stanford type B aortic dissection (TBAD) is associated with relatively high rates of morbidity and mortality, and appropriate treatment selection is important for optimizing patient outcomes. Depending on individualized risk factors, clinical presentation, and imaging findings, patients are generally stratified to optimal medical therapy anchored by antihypertensives or thoracic endovascular aortic repair (TEVAR). Using standard anatomic imaging with CT or MRI, several high-risk features including aortic diameter, false lumen (FL) features, size of entry tears, involvement of major aortic branch vessels, or evidence of visceral malperfusion have been used to select patients likely to benefit from TEVAR. However, even with these measures, the number needed to treat for TEVAR remains, and improved risk stratification is needed. Increasingly, the relationship between FL hemodynamics and adverse aortic remodeling in TBAD has been studied, and evolving noninvasive techniques can measure numerous FL hemodynamic parameters that may improve risk stratification. In addition to summarizing the current clinical state of the art for morphologic TBAD evaluation, this review provides a detailed overview of noninvasive methods for TBAD hemodynamics characterization, including computational fluid dynamics and four-dimensional flow MRI. Keywords: CT, Image Postprocessing, MRI, Cardiac, Vascular, Aorta, Dissection © RSNA, 2021.
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Affiliation(s)
- Zachary A Zilber
- Department of Radiology (Z.A.Z., A.B., B.D.A.), Department of Surgery-Division of Cardiac Surgery (S.C.M., C.K.M.), Department of Surgery-Division of Vascular Surgery (A.W.H.), and Department of Medicine-Division of Cardiology (P.V.), Northwestern University Feinberg School of Medicine, 676 N St Clair St, Suite 800, Chicago, IL 60611; Department of Radiology, University of Michigan, Ann Arbor, Mich (N.S.B.); Departments of Mechanical Engineering and Radiology, University of Wisconsin-Madison, Madison, Wis (A.R.A.); and Department of Radiology, Mayo Clinic, Rochester, Minn (J.D.C., C.J.F.)
| | - Aayush Boddu
- Department of Radiology (Z.A.Z., A.B., B.D.A.), Department of Surgery-Division of Cardiac Surgery (S.C.M., C.K.M.), Department of Surgery-Division of Vascular Surgery (A.W.H.), and Department of Medicine-Division of Cardiology (P.V.), Northwestern University Feinberg School of Medicine, 676 N St Clair St, Suite 800, Chicago, IL 60611; Department of Radiology, University of Michigan, Ann Arbor, Mich (N.S.B.); Departments of Mechanical Engineering and Radiology, University of Wisconsin-Madison, Madison, Wis (A.R.A.); and Department of Radiology, Mayo Clinic, Rochester, Minn (J.D.C., C.J.F.)
| | - S Chris Malaisrie
- Department of Radiology (Z.A.Z., A.B., B.D.A.), Department of Surgery-Division of Cardiac Surgery (S.C.M., C.K.M.), Department of Surgery-Division of Vascular Surgery (A.W.H.), and Department of Medicine-Division of Cardiology (P.V.), Northwestern University Feinberg School of Medicine, 676 N St Clair St, Suite 800, Chicago, IL 60611; Department of Radiology, University of Michigan, Ann Arbor, Mich (N.S.B.); Departments of Mechanical Engineering and Radiology, University of Wisconsin-Madison, Madison, Wis (A.R.A.); and Department of Radiology, Mayo Clinic, Rochester, Minn (J.D.C., C.J.F.)
| | - Andrew W Hoel
- Department of Radiology (Z.A.Z., A.B., B.D.A.), Department of Surgery-Division of Cardiac Surgery (S.C.M., C.K.M.), Department of Surgery-Division of Vascular Surgery (A.W.H.), and Department of Medicine-Division of Cardiology (P.V.), Northwestern University Feinberg School of Medicine, 676 N St Clair St, Suite 800, Chicago, IL 60611; Department of Radiology, University of Michigan, Ann Arbor, Mich (N.S.B.); Departments of Mechanical Engineering and Radiology, University of Wisconsin-Madison, Madison, Wis (A.R.A.); and Department of Radiology, Mayo Clinic, Rochester, Minn (J.D.C., C.J.F.)
| | - Christopher K Mehta
- Department of Radiology (Z.A.Z., A.B., B.D.A.), Department of Surgery-Division of Cardiac Surgery (S.C.M., C.K.M.), Department of Surgery-Division of Vascular Surgery (A.W.H.), and Department of Medicine-Division of Cardiology (P.V.), Northwestern University Feinberg School of Medicine, 676 N St Clair St, Suite 800, Chicago, IL 60611; Department of Radiology, University of Michigan, Ann Arbor, Mich (N.S.B.); Departments of Mechanical Engineering and Radiology, University of Wisconsin-Madison, Madison, Wis (A.R.A.); and Department of Radiology, Mayo Clinic, Rochester, Minn (J.D.C., C.J.F.)
| | - Patricia Vassallo
- Department of Radiology (Z.A.Z., A.B., B.D.A.), Department of Surgery-Division of Cardiac Surgery (S.C.M., C.K.M.), Department of Surgery-Division of Vascular Surgery (A.W.H.), and Department of Medicine-Division of Cardiology (P.V.), Northwestern University Feinberg School of Medicine, 676 N St Clair St, Suite 800, Chicago, IL 60611; Department of Radiology, University of Michigan, Ann Arbor, Mich (N.S.B.); Departments of Mechanical Engineering and Radiology, University of Wisconsin-Madison, Madison, Wis (A.R.A.); and Department of Radiology, Mayo Clinic, Rochester, Minn (J.D.C., C.J.F.)
| | - Nicholas S Burris
- Department of Radiology (Z.A.Z., A.B., B.D.A.), Department of Surgery-Division of Cardiac Surgery (S.C.M., C.K.M.), Department of Surgery-Division of Vascular Surgery (A.W.H.), and Department of Medicine-Division of Cardiology (P.V.), Northwestern University Feinberg School of Medicine, 676 N St Clair St, Suite 800, Chicago, IL 60611; Department of Radiology, University of Michigan, Ann Arbor, Mich (N.S.B.); Departments of Mechanical Engineering and Radiology, University of Wisconsin-Madison, Madison, Wis (A.R.A.); and Department of Radiology, Mayo Clinic, Rochester, Minn (J.D.C., C.J.F.)
| | - Alejandro Roldán-Alzate
- Department of Radiology (Z.A.Z., A.B., B.D.A.), Department of Surgery-Division of Cardiac Surgery (S.C.M., C.K.M.), Department of Surgery-Division of Vascular Surgery (A.W.H.), and Department of Medicine-Division of Cardiology (P.V.), Northwestern University Feinberg School of Medicine, 676 N St Clair St, Suite 800, Chicago, IL 60611; Department of Radiology, University of Michigan, Ann Arbor, Mich (N.S.B.); Departments of Mechanical Engineering and Radiology, University of Wisconsin-Madison, Madison, Wis (A.R.A.); and Department of Radiology, Mayo Clinic, Rochester, Minn (J.D.C., C.J.F.)
| | - Jeremy D Collins
- Department of Radiology (Z.A.Z., A.B., B.D.A.), Department of Surgery-Division of Cardiac Surgery (S.C.M., C.K.M.), Department of Surgery-Division of Vascular Surgery (A.W.H.), and Department of Medicine-Division of Cardiology (P.V.), Northwestern University Feinberg School of Medicine, 676 N St Clair St, Suite 800, Chicago, IL 60611; Department of Radiology, University of Michigan, Ann Arbor, Mich (N.S.B.); Departments of Mechanical Engineering and Radiology, University of Wisconsin-Madison, Madison, Wis (A.R.A.); and Department of Radiology, Mayo Clinic, Rochester, Minn (J.D.C., C.J.F.)
| | - Christopher J François
- Department of Radiology (Z.A.Z., A.B., B.D.A.), Department of Surgery-Division of Cardiac Surgery (S.C.M., C.K.M.), Department of Surgery-Division of Vascular Surgery (A.W.H.), and Department of Medicine-Division of Cardiology (P.V.), Northwestern University Feinberg School of Medicine, 676 N St Clair St, Suite 800, Chicago, IL 60611; Department of Radiology, University of Michigan, Ann Arbor, Mich (N.S.B.); Departments of Mechanical Engineering and Radiology, University of Wisconsin-Madison, Madison, Wis (A.R.A.); and Department of Radiology, Mayo Clinic, Rochester, Minn (J.D.C., C.J.F.)
| | - Bradley D Allen
- Department of Radiology (Z.A.Z., A.B., B.D.A.), Department of Surgery-Division of Cardiac Surgery (S.C.M., C.K.M.), Department of Surgery-Division of Vascular Surgery (A.W.H.), and Department of Medicine-Division of Cardiology (P.V.), Northwestern University Feinberg School of Medicine, 676 N St Clair St, Suite 800, Chicago, IL 60611; Department of Radiology, University of Michigan, Ann Arbor, Mich (N.S.B.); Departments of Mechanical Engineering and Radiology, University of Wisconsin-Madison, Madison, Wis (A.R.A.); and Department of Radiology, Mayo Clinic, Rochester, Minn (J.D.C., C.J.F.)
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10
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Burris NS, Nordsletten DA, Sotelo JA, Grogan-Kaylor R, Houben IB, Figueroa CA, Uribe S, Patel HJ. False lumen ejection fraction predicts growth in type B aortic dissection: preliminary results. Eur J Cardiothorac Surg 2021; 57:896-903. [PMID: 31821480 DOI: 10.1093/ejcts/ezz343] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 11/06/2019] [Accepted: 11/13/2019] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES Current risk assessment strategies in type B aortic dissection are focused on anatomic parameters, although haemodynamic abnormalities that result in false lumen (FL) pressurization are thought to play a significant role in aortic growth. The objective of this study was to evaluate blood flow of the FL using 4D flow magnetic resonance imaging (MRI) and identify haemodynamic and anatomic factors that independently predict the rate of aortic growth. METHODS Patients with dissection of the descending thoraco-abdominal aorta (n = 18) were enrolled in a prospective observational study and underwent 4D flow MRI for haemodynamic assessment of the entry tear and FL. Anatomic parameters were obtained by magnetic resonance angiography and baseline computed tomography. False lumen ejection fraction (FL EF) was defined the ratio of retrograde flow rate at the dominant entry tear during diastole over the antegrade systolic flow rate. RESULTS The median aortic growth rate was 3.5 mm/year (interquartile range 0.5-8.1 mm/year). Entry tear peak velocity was lower in patients with enlarging aortic dimensions (95.5 ± 24.1 vs 128.1 ± 37.4 cm/s, P = 0.039). After adjusting for co-variates FL EF (β = 0.15, P = 0.004), baseline maximal aortic diameter (β = 0.37, P = 0.001) and the entry tear distance from the left subclavian artery (β = 0.07, P = 0.016) were significant predictors of aortic growth rate. CONCLUSIONS Beyond standard anatomic risk factors, FL EF is an independent predictor of aortic growth rate and may represent an intuitive, non-invasive method to estimate FL pressurization and improve patient-specific risk assessment in patients with type B aortic dissection.
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Affiliation(s)
| | - David A Nordsletten
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI, USA.,Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Julio A Sotelo
- Biomedical Imaging Center, Pontificia Universidad Católica de Chile, Santiago, Chile.,Department of Electrical Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile.,Millennium Nucleus for Cardiovascular Magnetic Resonance, Santiago, Chile
| | | | - Ignas B Houben
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI, USA
| | - C Alberto Figueroa
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.,Department of Surgery, University of Michigan, Ann Arbor, MI, USA
| | - Sergio Uribe
- Biomedical Imaging Center, Pontificia Universidad Católica de Chile, Santiago, Chile.,Millennium Nucleus for Cardiovascular Magnetic Resonance, Santiago, Chile.,Department of Radiology, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Himanshu J Patel
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI, USA
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11
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Comparative Outcome Analysis of N-Butyl Cyanoacrylate Embolization of the False Lumen Versus Thoracic Endovascular Aortic Repair in Aortic Dissection. J Vasc Interv Radiol 2020; 32:39-48. [PMID: 33246735 DOI: 10.1016/j.jvir.2020.08.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 08/29/2020] [Accepted: 08/31/2020] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To evaluate the feasibility, safety, and effectiveness of N-butyl cyanoacrylate (NBCA) embolization for the treatment of aortic dissection. MATERIALS AND METHODS In this single-center retrospective study conducted from February 2003 to June 2019, NBCA embolization of an aortic false lumen was attempted in 12 patients (median age, 59 y; range, 41-68 y) and thoracic endovascular aortic repair (TEVAR) was performed in 53 patients (median age, 59 y; range, 37-70 y) for aortic dissection with one or more indications of persisting pain, malperfusion, rupture or impending rupture, maximal aortic diameter ≥ 55 mm, and/or rapid aortic enlargement. The main exclusion criterion for embolization was the presence of fast blood flow in the aortic false lumen on aortography. The efficacy of NBCA embolization and TEVAR was compared by evaluating technical and clinical outcomes, repeat intervention-free survival (RFS), and overall survival (OS). RESULTS Technical success was achieved in 11 of the 12 patients treated with NBCA embolization (91.7%), and clinical success was achieved in 9 of these 11 (81.8%). No significant difference was found between embolization and TEVAR in clinical success rates (embolization, 81.8%; TEVAR, 84.9%; P = .409) or procedure-related complications (embolization, 1 patient [8.3%]; TEVAR, 4 patients [7.5%]; P = .701). In addition, embolization showed comparable 5-y RFS (embolization, 82.5% ± 9.3; TEVAR, 85.5% ± 4.8; P = .641) and 5-y OS (embolization, 100%; TEVAR, 95.4% ± 3.2; P = .744) rates to TEVAR. CONCLUSIONS NBCA embolization of the false lumen in aortic dissection seems to be a safe and effective treatment modality for the closure of false lumen in selected patients.
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12
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Bäumler K, Vedula V, Sailer AM, Seo J, Chiu P, Mistelbauer G, Chan FP, Fischbein MP, Marsden AL, Fleischmann D. Fluid-structure interaction simulations of patient-specific aortic dissection. Biomech Model Mechanobiol 2020; 19:1607-1628. [PMID: 31993829 DOI: 10.1007/s10237-020-01294-8] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 01/14/2020] [Indexed: 12/01/2022]
Abstract
Credible computational fluid dynamic (CFD) simulations of aortic dissection are challenging, because the defining parallel flow channels-the true and the false lumen-are separated from each other by a more or less mobile dissection membrane, which is made up of a delaminated portion of the elastic aortic wall. We present a comprehensive numerical framework for CFD simulations of aortic dissection, which captures the complex interplay between physiologic deformation, flow, pressures, and time-averaged wall shear stress (TAWSS) in a patient-specific model. Our numerical model includes (1) two-way fluid-structure interaction (FSI) to describe the dynamic deformation of the vessel wall and dissection flap; (2) prestress and (3) external tissue support of the structural domain to avoid unphysiologic dilation of the aortic wall and stretching of the dissection flap; (4) tethering of the aorta by intercostal and lumbar arteries to restrict translatory motion of the aorta; and a (5) independently defined elastic modulus for the dissection flap and the outer vessel wall to account for their different material properties. The patient-specific aortic geometry is derived from computed tomography angiography (CTA). Three-dimensional phase contrast magnetic resonance imaging (4D flow MRI) and the patient's blood pressure are used to inform physiologically realistic, patient-specific boundary conditions. Our simulations closely capture the cyclical deformation of the dissection membrane, with flow simulations in good agreement with 4D flow MRI. We demonstrate that decreasing flap stiffness from [Formula: see text] to [Formula: see text] kPa (a) increases the displacement of the dissection flap from 1.4 to 13.4 mm, (b) decreases the surface area of TAWSS by a factor of 2.3, (c) decreases the mean pressure difference between true lumen and false lumen by a factor of 0.63, and (d) decreases the true lumen flow rate by up to 20% in the abdominal aorta. We conclude that the mobility of the dissection flap substantially influences local hemodynamics and therefore needs to be accounted for in patient-specific simulations of aortic dissection. Further research to accurately measure flap stiffness and its local variations could help advance future CFD applications.
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Affiliation(s)
- Kathrin Bäumler
- 3D and Quantitative Imaging Laboratory, Department of Radiology, Stanford University, Stanford, CA, 94305, USA.
| | - Vijay Vedula
- Department of Pediatrics (Cardiology), Stanford University, Stanford, CA, 94305, USA
| | - Anna M Sailer
- 3D and Quantitative Imaging Laboratory, Department of Radiology, Stanford University, Stanford, CA, 94305, USA
| | - Jongmin Seo
- Department of Pediatrics (Cardiology), Stanford University, Stanford, CA, 94305, USA
| | - Peter Chiu
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, 94305, USA
| | - Gabriel Mistelbauer
- Department of Simulation and Graphics, University of Magdeburg, Magdeburg, Germany
| | - Frandics P Chan
- 3D and Quantitative Imaging Laboratory, Department of Radiology, Stanford University, Stanford, CA, 94305, USA
| | - Michael P Fischbein
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, 94305, USA
| | - Alison L Marsden
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
| | - Dominik Fleischmann
- 3D and Quantitative Imaging Laboratory, Department of Radiology, Stanford University, Stanford, CA, 94305, USA
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13
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Computational modeling of the fluid flow in type B aortic dissection using a modified finite element embedded formulation. Biomech Model Mechanobiol 2020; 19:1565-1583. [PMID: 31974816 DOI: 10.1007/s10237-020-01291-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 01/14/2020] [Indexed: 10/25/2022]
Abstract
This work explores the use of an embedded computational fluid dynamics method to study the type B aortic dissection. The use of the proposed technique makes it possible to easily test different intimal flap configurations without any need of remeshing. To validate the presented methodology, we take as reference test case an in vitro experiment present in the literature. This experiment, which considers several intimal flap tear configurations (number, size and location), mimics the blood flow in a real type B aortic dissection. We prove the correctness and suitability of the presented approach by comparing the pressure values and waveform. The obtained results exhibit a remarkable similarity with the experimental reference data. Complementary, we present a feasible surgical application of the presented computer method. The aim is to help the clinicians in the decision making before the type B aortic dissection surgical fenestration. The capabilities of the proposed technique are exploited to efficiently create artificial reentry tear configurations. We highlight that only the radius and center of the reentry tear need to be specified by the clinicians, without any need to modify neither the model geometry nor the mesh. The obtained computational surgical fenestration results are in line with the medical observations in similar clinical studies.
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14
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Experimental Insight into the Hemodynamics and Perfusion of Radiological Contrast in Patent and Non-patent Aortic Dissection Models. Cardiovasc Eng Technol 2019; 10:314-328. [PMID: 30805874 DOI: 10.1007/s13239-019-00407-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 02/09/2019] [Indexed: 10/27/2022]
Abstract
PURPOSE In a curved vessel such as the aortic arch, the velocity profile closer to the aortic root is normally skewed towards the inner curvature wall, while further downstream along the curve, the velocity profile becomes skewed towards the outer wall. In an aortic dissection (AD) disease, blood velocities in the true lumen (TL) and false lumen (FL) are hypothesized to depend on the proximity of the entry tear to the root of aortic arch. Faster velocity in the FL can lead to higher hemodynamic loading, and pose tearing risk. Furthermore, the luminal velocities control the perfusion rate of radiological contrast media during diagnostic imaging. The objective in this study is to investigate the effect of AD disease morphology and configuration on the blood velocity field in the TL and FL, and on the relative perfusion of radiological enhancement agents through the dissection. METHODS Eight in vitro models were studied, including patent and non-patent FL configurations. Particle image velocimetry (PIV) was used to quantify the AD velocity field, while laser-induced fluorescence (LIF) was implemented to visualize dynamical flow phenomena and to quantify the perfusion of injected dye, in mimicry of contrast-enhanced computed tomography (CT). RESULTS The location of the proximal entry tear along the aortic arch in a patent FL had a dramatic impact on whether the blood velocity was higher in the TL or FL. The luminal velocities were dependent on the entry/reentry tear size combination, with the smaller tear (whether distal or proximal) setting the upper limit on the maximal flow velocity in the FL. Upon merging near the distal reentry tear, the TL/FL velocity differential gave rise to the roll up and shedding of shear layer vortices that convected downstream in close proximity to the wall of the non-dissected aorta. In a non-patent FL, the flow velocity was practically null with all the blood passing through the TL. LIF imaging showed much slower perfusion of contrast dye in the FL compared to the TL. In a patent FL, however, dye had a comparable perfusion rate appearing around the same time as in the TL. CONCLUSIONS Blood velocities in the TL and FL were highly sensitive to the exact dissection configuration. Geometric case A1R, which had its proximal entry tear located further downstream along the aortic arch, and had its entry and reentry tears sufficiently sized, exhibited the highest FL flow velocity among the tested models, and it was also higher than in the TL, which suggest that this configuration had elevated hemodynamic loading and risk for tearing. In contrast-enhanced diagnostic imaging, a time-delayed acquisition protocol is recommended to improve the detection of suspected cases with a non-patent FL.
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15
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Ahuja A, Noblet JN, Trudnowski T, Patel B, Krieger JF, Chambers S, Kassab GS. Biomechanical Material Characterization of Stanford Type-B Dissected Porcine Aortas. Front Physiol 2018; 9:1317. [PMID: 30319438 PMCID: PMC6169260 DOI: 10.3389/fphys.2018.01317] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 08/30/2018] [Indexed: 11/24/2022] Open
Abstract
Aortic dissection (AD) involves tearing of the medial layer, creating a blood-filled channel called false lumen (FL). To treat dissections, clinicians are using endovascular therapy using stent grafts to seal the FL. This procedure has been successful in reducing mortality but has failed in completely re-attaching the torn intimal layer. The use of computational analysis can predict the radial forces needed to devise stents that can treat ADs. To quantify the hyperelastic material behavior for therapy development, we harvested FL wall, true lumen (TL) wall, and intimal flap from the middle and distal part of five dissected aortas. Planar biaxial testing using multiple stretch protocols were conducted on tissue samples to quantify their deformation behavior. A novel non-linear regression model was used to fit data against Holzapfel–Gasser–Ogden hyperelastic strain energy function. The fitting analysis correlated the behavior of the FL and TL walls and the intimal flap to the stiffness observed during tensile loading. It was hypothesized that there is a variability in the stresses generated during loading among tissue specimens derived from different regions of the dissected aorta and hence, one should use region-specific material models when simulating type-B AD. From the data on material behavior analysis, the variability in the tissue specimens harvested from pigs was tabulated using stress and coefficient of variation (CV). The material response curves also compared the changes in compliance observed in the FL wall, TL wall, and intimal flap for middle and distal regions of the dissection. It was observed that for small stretch ratios, all the tissue specimens behaved isotropically with overlapping stress–stretch curves in both circumferential and axial directions. As the stretch ratios increased, we observed that most tissue specimens displayed different structural behaviors in axial and circumferential directions. This observation was very apparent in tissue specimens from mid FL region, less apparent in mid TL, distal FL, and distal flap tissues and least noticeable in tissue specimens harvested from mid flap. Lastly, using mixed model ANOVAS, it was concluded that there were significant differences between mid and distal regions along axial direction which were absent in the circumferential direction.
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Affiliation(s)
- Aashish Ahuja
- Cardiovascular Mechanics and Diseases, California Medical Innovations Institute, San Diego, CA, United States
| | | | | | - Bhavesh Patel
- Cardiovascular Mechanics and Diseases, California Medical Innovations Institute, San Diego, CA, United States
| | | | | | - Ghassan S Kassab
- Cardiovascular Mechanics and Diseases, California Medical Innovations Institute, San Diego, CA, United States
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16
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Ahuja A, Guo X, Noblet JN, Krieger JF, Roeder B, Haulon S, Chambers S, Kassab GS. Validated Computational Model to Compute Re-apposition Pressures for Treating Type-B Aortic Dissections. Front Physiol 2018; 9:513. [PMID: 29867557 PMCID: PMC5954206 DOI: 10.3389/fphys.2018.00513] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Accepted: 04/20/2018] [Indexed: 11/13/2022] Open
Abstract
The use of endovascular treatment in the thoracic aorta has revolutionized the clinical approach for treating Stanford type B aortic dissection. The endograft procedure is a minimally invasive alternative to traditional surgery for the management of complicated type-B patients. The endograft is first deployed to exclude the proximal entry tear to redirect blood flow toward the true lumen and then a stent graft is used to push the intimal flap against the false lumen (FL) wall such that the aorta is reconstituted by sealing the FL. Although endovascular treatment has reduced the mortality rate in patients compared to those undergoing surgical repair, more than 30% of patients who were initially successfully treated require a new endovascular or surgical intervention in the aortic segments distal to the endograft. One reason for failure of the repair is persistent FL perfusion from distal entry tears. This creates a patent FL channel which can be associated with FL growth. Thus, it is necessary to develop stents that can promote full re-apposition of the flap leading to complete closure of the FL. In the current study, we determine the radial pressures required to re-appose the mid and distal ends of a dissected porcine thoracic aorta using a balloon catheter under static inflation pressure. The same analysis is simulated using finite element analysis (FEA) models by incorporating the hyperelastic properties of porcine aortic tissues. It is shown that the FEA models capture the change in the radial pressures required to re-appose the intimal flap as a function of pressure. The predictions from the simulation models match closely the results from the bench experiments. The use of validated computational models can support development of better stents by calculating the proper radial pressures required for complete re-apposition of the intimal flap.
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Affiliation(s)
- Aashish Ahuja
- California Medical Innovations Institute, San Diego, CA, United States
| | - Xiaomei Guo
- California Medical Innovations Institute, San Diego, CA, United States
| | | | | | | | - Stephan Haulon
- Aortic Center, Hôpital Marie Lannelongue, Université Paris Sud, Paris, France
| | | | - Ghassan S Kassab
- California Medical Innovations Institute, San Diego, CA, United States
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