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Kim T, van Bakel PAJ, Nama N, Burris N, Patel HJ, Williams DM, Figueroa CA. A Computational Study of Dynamic Obstruction in Type B Aortic Dissection. J Biomech Eng 2023; 145:031008. [PMID: 36459144 PMCID: PMC10854260 DOI: 10.1115/1.4056355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 11/18/2022] [Accepted: 11/21/2022] [Indexed: 12/05/2022]
Abstract
A serious complication in aortic dissection is dynamic obstruction of the true lumen (TL). Dynamic obstruction results in malperfusion, a blockage of blood flow to a vital organ. Clinical data reveal that increases in central blood pressure promote dynamic obstruction. However, the mechanisms by which high pressures result in TL collapse are underexplored and poorly understood. Here, we developed a computational model to investigate biomechanical and hemodynamical factors involved in Dynamic obstruction. We hypothesize that relatively small pressure gradient between TL and false lumen (FL) are sufficient to displace the flap and induce obstruction. An idealized fluid-structure interaction model of type B aortic dissection was created. Simulations were performed under mean cardiac output while inducing dynamic changes in blood pressure by altering FL outflow resistance. As FL resistance increased, central aortic pressure increased from 95.7 to 115.3 mmHg. Concurrent with blood pressure increase, flap motion was observed, resulting in TL collapse, consistent with clinical findings. The maximum pressure gradient between TL and FL over the course of the dynamic obstruction was 4.5 mmHg, consistent with our hypothesis. Furthermore, the final stage of dynamic obstruction was very sudden in nature, occurring over a short time (<1 s) in our simulation, consistent with the clinical understanding of this dramatic event. Simulations also revealed sudden drops in flow and pressure in the TL in response to the flap motion, consistent with first stages of malperfusion. To our knowledge, this study represents the first computational analysis of potential mechanisms driving dynamic obstruction in aortic dissection.
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Affiliation(s)
- T Kim
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48105
| | - P A J van Bakel
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI 48105
| | - N Nama
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588
| | - N Burris
- Department of Radiology, University of Michigan, Ann Arbor, MI 48105
| | - H J Patel
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI 48105
| | - D M Williams
- Department of Radiology, University of Michigan, Ann Arbor, MI 48105
| | - C A Figueroa
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48105; Department of Surgery, University of Michigan, Ann Arbor, MI 48105
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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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Wang Y, Song S, Zhou C, Zhu W, Liu J, Shi Q, Huang S, Yang C, Li T, Chen Y, Xiong B. Thoracic Endovascular Aortic Repair for Retrograde Type A Intramural Hematoma With Intimal Disruption in the Descending Aorta. J Endovasc Ther 2021; 29:724-730. [PMID: 34852656 DOI: 10.1177/15266028211061268] [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: 11/17/2022]
Abstract
PURPOSE To evaluate the safety and efficacy of thoracic endovascular aortic repair (TEVAR) for retrograde type A intramural hematoma (IMH) with intimal disruption in the descending aorta and report our endovascular therapeutic experience. MATERIALS AND METHODS From January 2014 to October 2020, a total of 24 consecutive patients with retrograde type A IMH with intimal disruption (intimal tear or ulcer-like projection) in the descending aorta underwent TEVAR. The demographics, clinical characteristics, treatment details, imaging information, and follow-up results were reviewed. RESULTS Among all patients with retrograde type A IMH, 13 (54.2%) patients presented with ulcer-like projection and 11 (45.8%) with intimal tear (aortic dissection) in the descending aorta. Successful TEVAR was achieved in all patients. There was no 30-day mortality. During a mean follow-up of 37.5 months, 1 patient (4.2%) developed permanent paralysis, 1 patient (4.2%) underwent reintervention due to the expansion of the aorta distal to the stent resulting from the enlargement of distal intimal tear at the 2 month follow up, and no other adverse events were observed. The latest computed tomographic angiography images showed that the maximum diameter of the ascending aorta and descending aorta significantly decreased after TEVAR (both p<0.001), and the IMH/false lumen in the ascending aorta and the descending thoracic aorta were completely absorbed. CONCLUSION Thoracic endovascular aortic repair for selected patients with retrograde type A intramural hematoma that presented with intimal disruption in the descending aorta is feasible and efficient, but close surveillance is needed to manage aortic-related adverse events.
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Affiliation(s)
- Yingliang Wang
- Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Key Laboratory of Molecular Imaging, Wuhan, China
| | - Songlin Song
- Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Key Laboratory of Molecular Imaging, Wuhan, China
| | - Chen Zhou
- Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Key Laboratory of Molecular Imaging, Wuhan, China
| | - Wenying Zhu
- Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Key Laboratory of Molecular Imaging, Wuhan, China
| | - Jiacheng Liu
- Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Key Laboratory of Molecular Imaging, Wuhan, China
| | - Qin Shi
- Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Key Laboratory of Molecular Imaging, Wuhan, China
| | - Songjiang Huang
- Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Key Laboratory of Molecular Imaging, Wuhan, China
| | - Chongtu Yang
- Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Key Laboratory of Molecular Imaging, Wuhan, China
| | - Tongqiang Li
- Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Key Laboratory of Molecular Imaging, Wuhan, China
| | - Yang Chen
- Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Key Laboratory of Molecular Imaging, Wuhan, China
| | - Bin Xiong
- Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Key Laboratory of Molecular Imaging, Wuhan, China
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Chong MY, Gu B, Chan BT, Ong ZC, Xu XY, Lim E. Effect of intimal flap motion on flow in acute type B aortic dissection by using fluid-structure interaction. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2020; 36:e3399. [PMID: 32862487 DOI: 10.1002/cnm.3399] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 08/18/2020] [Accepted: 08/25/2020] [Indexed: 06/11/2023]
Abstract
A monolithic, fully coupled fluid-structure interaction (FSI) computational framework was developed to account for dissection flap motion in acute type B aortic dissection (TBAD). Analysis of results included wall deformation, pressure, flow, wall shear stress (WSS), von Mises stress and comparison of hemodynamics between rigid wall and FSI models. Our FSI model mimicked realistic wall deformation that resulted in maximum compression of the distal true lumen (TL) by 21.4%. The substantial movement of intimal flap mostly affected flow conditions in the false lumen (FL). Flap motion facilitated more flow entering the FL at peak systole, with the TL to FL flow split changing from 88:12 in the rigid model to 83:17 in the FSI model. There was more disturbed flow in the FL during systole (5.8% FSI vs 5.2% rigid) and diastole (13.5% FSI vs 9.8% rigid), via a λ2 -criterion. The flap-induced disturbed flow near the tears in the FSI model caused an increase of local WSS by up to 70.0% during diastole. This resulted in a significant reduction in the size of low time-averaged WSS (TAWSS) regions in the FL (113.11 cm2 FSI vs 177.44 cm2 rigid). Moreover, the FSI model predicted lower systolic pressure, higher diastolic pressure, and hence lower pulse pressure. Our results provided new insights into the possible impact of flap motion on flow in aortic dissections, which are particularly important when evaluating hemodynamics of acute TBAD. NOVELTY STATEMENT: Our monolithic fully coupled FSI computational framework is able to reproduce experimentally measured range of flap deformation in aortic dissection, thereby providing novel insights into the influence of physiological flap motion on the flow and pressure distributions. The drastic flap movement increases the flow resistance in the true lumen and causes more disturbed flow in the false lumen, as visualized through the λ2 criterion. The flap-induced luminal pressure is dampened, thereby affecting pressure measures, which may serve as potential prognostic indicators for late complications in acute uncomplicated TBAD patients.
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Affiliation(s)
- Mei Yan Chong
- Department of Biomedical Engineering, University of Malaya, Kuala Lumpur, Malaysia
- Department of Chemical Engineering, Imperial College London, London, UK
| | - Boram Gu
- Department of Chemical Engineering, Imperial College London, London, UK
| | - Bee Ting Chan
- Department of Mechanical, Materials and Manufacturing Engineering, University of Nottingham, Nottingham, UK
| | - Zhi Chao Ong
- Department of Mechanical Engineering, University of Malaya, Kuala Lumpur, Malaysia
| | - Xiao Yun Xu
- Department of Chemical Engineering, Imperial College London, London, UK
| | - Einly Lim
- Department of Biomedical Engineering, University of Malaya, Kuala Lumpur, Malaysia
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Huang CY, Hsu HL, Chen PL, Kuo TT, Chen IM, Hsu CP, Shih CC. Aortic remodeling after hybrid provisional extension to induce complete attachment aortic repair of chronic residual type I aortic dissection. J Thorac Cardiovasc Surg 2019; 158:1007-1016. [DOI: 10.1016/j.jtcvs.2018.12.041] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2018] [Revised: 11/27/2018] [Accepted: 12/10/2018] [Indexed: 10/27/2022]
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Miura S, Kurimoto Y, Maruyama R, Wada T, Konno M, Iba Y, Hatta E, Yamada A. Thoracic Endovascular Aortic Repair on Zone 2 Landing for Type B Aortic Dissection. Ann Vasc Surg 2019; 60:120-127. [DOI: 10.1016/j.avsg.2019.02.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 02/16/2019] [Accepted: 02/17/2019] [Indexed: 01/10/2023]
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Zhang S, Chen Y, Zhang Y, Shi D, Shen Y, Bao J, Zhao Z, Feng X, Feng R, Zhou J, Lu Q, Jing Z. Should the distal tears of aortic dissection be treated? The risk of distal tears after proximal repair of aortic dissection. Int J Cardiol 2018; 261:162-166. [PMID: 29657039 DOI: 10.1016/j.ijcard.2018.01.028] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 12/14/2017] [Accepted: 01/08/2018] [Indexed: 10/17/2022]
Abstract
BACKGROUND Patients with distal residual after proximal repair of aortic dissection (AD) have shown unsatisfactory long-term prognosis. However, possible mechanisms and risk factors for distal aortic segmental enlargement (DSAE) have been poorly understood. METHODS We analyzed 962 AD patients repaired to the descending aorta between 1999 and 2014. Aortic morphological characteristics of 419 patients (including 75 DSAE and 344 non-DSAE patients) were investigated and compared. Potential risk factors associated with DSAE were explored using logistic regression analysis or natural logarithmic transformation. Logistic multi regress equations were performed to identify independent risk factors. RESULTS Independent risk factors of DSAE are listed as follow: more tears in the thoracic descending aorta (odds ratio [OR], 1.65; 95% confidence interval [CI],1.24 to 2.19; P = .0005); fewer tears in the infra-renal abdominal aorta (OR, 3.00; 95% CI,2.04 to 4.55; P < .0001); closer distance of the first intimal tear to the left subclavian artery (OR, 1.51; 95% CI,1.28 to 1.69; P < .0001); larger average distance between tears (OR, 11.81; 95% CI,3.39 to 41.08; P = .0001); larger maximum distance between two tears (OR, 1.79; 95% CI,1.48 to 2.16; P < .0001), and larger area of remained tears (OR, 1.56; 95% CI, 1.38 to 1.76; P < .0001). CONCLUSIONS The location and size of remained tears are the key risk factors of DSAE patients. Long-segment aortic repair and aggressive exclusion of all distal tears located on the thoracic descending aorta in their initial therapy will be an optimal strategy.
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Affiliation(s)
- Simeng Zhang
- Department of Vascular Surgery, Changhai Hospital, Shanghai, China
| | - Yanqing Chen
- Department of Vascular Surgery, Changhai Hospital, Shanghai, China
| | - Yongxue Zhang
- Department of General Surgery, 285th Hospital, the Chinese People's Liberation Army, Handan, China
| | - Dongchen Shi
- Department of Respiratory and Critical Care Medicine, Changhai Hospital, Shanghai, China
| | - Yu Shen
- Department of Vascular Surgery, Changhai Hospital, Shanghai, China
| | - Junmin Bao
- Department of Vascular Surgery, Changhai Hospital, Shanghai, China
| | - Zhiqing Zhao
- Department of Vascular Surgery, Changhai Hospital, Shanghai, China
| | - Xiang Feng
- Department of Vascular Surgery, Changhai Hospital, Shanghai, China
| | - Rui Feng
- Department of Vascular Surgery, Changhai Hospital, Shanghai, China
| | - Jian Zhou
- Department of Vascular Surgery, Changhai Hospital, Shanghai, China
| | - Qingsheng Lu
- Department of Vascular Surgery, Changhai Hospital, Shanghai, China.
| | - Zaiping Jing
- Department of Vascular Surgery, Changhai Hospital, Shanghai, China.
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Liu D, Fan Z, Li Y, Zhang N, Sun Z, An J, Stalder AF, Greiser A, Liu J. Quantitative Study of Abdominal Blood Flow Patterns in Patients with Aortic Dissection by 4-Dimensional Flow MRI. Sci Rep 2018; 8:9111. [PMID: 29904131 PMCID: PMC6002546 DOI: 10.1038/s41598-018-27249-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 05/31/2018] [Indexed: 11/09/2022] Open
Abstract
The purpose of this study is to evaluate the hemodynamic characteristics of the true lumen (TL) and the false lumen (FL) in 16 patients with aortic dissection (AD) using 4D flow magnetic resonance imaging (MRI) and thoracic and abdominal computed tomography (CT) angiography. The quantitative parameters that were measured in the TL and FL included velocity and flow. The mean area and regurgitant fraction of the TL were significantly lesser at all four levels (p < 0.05); the average through-plane velocity, peak velocity magnitude, average net flow, peak flow, and net forward volume in the TL were considerably higher (p < 0.05). The intimal entry's size was negatively correlated with the blood flow velocity and flow rate in the TL (p < 0.05) and positively correlated with the average through-plane velocity, average net flow, and peak flow in the FL (p < 0.05); the blood flow indices in the TL were enhanced with an increase in the intimal entry numbers (p < 0.05) and the peak flow in the FL was lowered (p = 0.025); if FL thrombosis existed, the average through-plane velocity and peak velocity magnitude in the TL were substantially higher (p < 0.05). 4D flow MRI facilitates qualitative and quantitative analysis of the alterations in the abdominal aortic blood flow patterns.
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Affiliation(s)
- Dongting Liu
- Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, 100029, China
| | - Zhanming Fan
- Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, 100029, China
| | - Yu Li
- Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, 100029, China
| | - Nan Zhang
- Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, 100029, China
| | - Zhonghua Sun
- Department of Medical Radiation Sciences, Curtin University, Perth, 6102, Australia
| | - Jing An
- Siemens Shenzhen Magnetic Resonance Ltd, Beijing, China
| | | | | | - Jiayi Liu
- Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, 100029, China.
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Liu D, Liu J, Wen Z, Li Y, Sun Z, Xu Q, Fan Z. 320-row CT renal perfusion imaging in patients with aortic dissection: A preliminary study. PLoS One 2017; 12:e0171235. [PMID: 28182709 PMCID: PMC5300209 DOI: 10.1371/journal.pone.0171235] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 01/17/2017] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVE To investigate the clinical value of renal perfusion imaging in patients with aortic dissection (AD) using 320-row computed tomography (CT), and to determine the relationship between renal CT perfusion imaging and various factors of aortic dissection. METHODS Forty-three patients with AD who underwent 320-row CT renal perfusion before operation were prospectively enrolled in this study. Diagnosis of AD was confirmed by transthoracic echocardiography. Blood flow (BF) of bilateral renal perfusion was measured and analyzed. CT perfusion imaging signs of AD in relation to the type of AD, number of entry tears and the false lumen thrombus were observed and compared. RESULTS The BF values of patients with type A AD were significantly lower than those of patients with type B AD (P = 0.004). No significant difference was found in the BF between different numbers of intimal tears (P = 0.288), but BF values were significantly higher in cases with a false lumen without thrombus and renal arteries arising from the true lumen than in those with thrombus (P = 0.036). The BF values measured between the true lumen, false lumen and overriding groups were different (P = 0.02), with the true lumen group having the highest. Also, the difference in BF values between true lumen and false lumen groups was statistically significant (P = 0.016), while no statistical significance was found in the other two groups (P > 0.05). The larger the size of intimal entry tears, the greater the BF values (P = 0.044). CONCLUSIONS This study shows a direct correlation between renal CT perfusion changes and AD, with the size, number of intimal tears, different types of AD, different renal artery origins and false lumen thrombosis, significantly affecting the perfusion values.
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Affiliation(s)
- Dongting Liu
- Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Jiayi Liu
- Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Zhaoying Wen
- Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Yu Li
- Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Zhonghua Sun
- Department of Medical Radiation Sciences, Curtin University, Perth, Australia
| | - Qin Xu
- School of Public Health, Capital Medical University, Beijing, China
| | - Zhanming Fan
- Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
- * E-mail:
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Khoynezhad A, Toluie S, Al-Atassi T. Treatment of the Chronic Type B Aortic Dissection: The Pro-endovascular Argument. Semin Thorac Cardiovasc Surg 2017; 29:131-136. [DOI: 10.1053/j.semtcvs.2017.03.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/15/2017] [Indexed: 11/11/2022]
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Computational Study of Anatomical Risk Factors in Idealized Models of Type B Aortic Dissection. Eur J Vasc Endovasc Surg 2016; 52:736-745. [PMID: 27561609 DOI: 10.1016/j.ejvs.2016.07.025] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 07/19/2016] [Indexed: 11/21/2022]
Abstract
OBJECTIVE/BACKGROUND Several risk factors have been identified in type B aortic dissection (TBAD), namely tear size, location, patency and number, and false lumen (FL) location. However, the individual impact of each of these factors is poorly understood. The impact of these factors was investigated using computational fluid dynamics (CFD). METHODS Fourteen idealized models of chronic TBAD were created of different shapes (straight vs. curved vessels), different number of proximal and distal tears, tear size (4, 10, and 20 mm diameter) and shape (circular or elliptical), FL location (inner or outer arch), treated (stented), and untreated. All models had identical length, relative size of true lumen (TL) and FL, and inlet (flow) and outlet (pressure) boundary conditions. Using validated CFD tools, inlet mean pressure (MP), pulse pressure (PP), TL and FL pressures, velocities, and flows were computed for each model. RESULTS AD increased PP and MP relative to undissected aorta. Curvature did not change pressure and flow ratio between TL and FL. Inner curvature FL showed slightly larger pressures and tear velocities. Larger tears decreased hemodynamic differences between TL and FL. The combination of proximal and distal tear size determines the overall hemodynamics: larger proximal tears increased FL PP by up to 76%. Conversely, larger distal tears decreased FL PP and MP. Large proximal and distal tears decreased tear velocity (by up to 65%) and increased FL flow (up to 12 times). Proximal tear stenting resulted in a 54% reduction of PP. Conversely, distal occlusion tear increased FL PP and MP by 144% and 7%, respectively. CONCLUSION Unfavorable hemodynamic conditions such as larger FL pressure occur when distal tear is small or absent, proximal tears are large, and FL is at the inner curvature, in agreement with previous clinical studies. CFD analysis is a powerful tool to understand the interplay between anatomy and hemodynamics in TBAD.
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Current Experience With Acute Type B Aortic Dissection: Validity of the Complication-Specific Approach in the Present Era. Ann Thorac Surg 2016; 101:936-43. [DOI: 10.1016/j.athoracsur.2015.08.074] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 08/14/2015] [Accepted: 08/31/2015] [Indexed: 11/21/2022]
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Kim JS, Park KH, Lim C, Kim DJ, Jung Y, Shin YC, Choi SI, Chun EJ, Yoo JY. Prediction of Intimal Tear Site by Computed Tomography in Acute Aortic Dissection Type A. Korean Circ J 2016; 46:48-55. [PMID: 26798385 PMCID: PMC4720849 DOI: 10.4070/kcj.2016.46.1.48] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 07/27/2015] [Accepted: 08/17/2015] [Indexed: 11/12/2022] Open
Abstract
Background and Objectives Preoperative identification of intimal tear site in acute type A dissection will help procedural planning. The objective of this study was to determine the key findings of computed tomography (CT)-based prediction for tear site and compare the accuracy between radiologists and surgeons. Subjects and Methods Multi-detector CT (MDCT) images from 50 patients who underwent surgical repair of type A aortic dissection were retrospectively reviewed by 4 cardiac surgeons with limited experience or by 3 radiologists specialized in cardiovascular imaging. Surgical findings of intimal tear site were used as references. Results In surgical findings, the locations of intimal tear that were identified in 43 patients included aorta (n=25), ascending with arch (n=7), and arch only (n=11). The rest were retrograde dissections from the tear of descending aorta. Key CT findings that were most frequently found were defect in the intimal flap shadow (30.0±4.0 patients/reviewer, accuracy 87.0±11.7%) and differential filling of false lumen by phase and location (9.4±2.9 patients/reviewer, 84.8±10.4%). Surgeons predicted tear site (75.0±7.7% vs. 86.7±1.2%, p=0.055) and specified flap defect (80.5±10.3% vs. 95.7±7.4%, p=0.073) with lower accuracy than radiologists. Conclusions With MDCT imaging, well-educated surgeons could be accurate in three fourths of cases. There was room for improvement through experience. Considering the substantial possibility of inaccuracy, critical decisions on CT images should be made through thorough reviewing by as many experienced radiologists and surgeons as possible.
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Affiliation(s)
- Jun Sung Kim
- Department of Thoracic and Cardiovascular Surgery, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Kay-Hyun Park
- Department of Thoracic and Cardiovascular Surgery, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Cheong Lim
- Department of Thoracic and Cardiovascular Surgery, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Dong Jin Kim
- Department of Thoracic and Cardiovascular Surgery, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Yochun Jung
- Department of Thoracic and Cardiovascular Surgery, Halla General Hospital, Jeju, Korea
| | - Yoon Cheol Shin
- Department of Thoracic and Cardiovascular Surgery, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Sang Il Choi
- Department of Radiology, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Eun Ju Chun
- Department of Radiology, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Jin Young Yoo
- Department of Radiology, Seoul National University Bundang Hospital, Seongnam, Korea
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Dillon-Murphy D, Noorani A, Nordsletten D, Figueroa CA. Multi-modality image-based computational analysis of haemodynamics in aortic dissection. Biomech Model Mechanobiol 2015; 15:857-76. [PMID: 26416312 PMCID: PMC4945697 DOI: 10.1007/s10237-015-0729-2] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 09/10/2015] [Indexed: 11/25/2022]
Abstract
Aortic dissection is a disease whereby an injury in the wall of the aorta leads to the creation of a true lumen and a false lumen separated by an intimal flap which may contain multiple communicating tears between the lumina. It has a high associated morbidity and mortality, but at present, the timing of surgical intervention for stable type B dissections remains an area of debate. Detailed knowledge of haemodynamics may yield greater insight into the long-term outcomes for dissection patients by providing a greater understanding of pressures, wall shear stress and velocities in and around the dissection. In this paper, we aim to gather further insight into the complex haemodynamics in aortic dissection using medical imaging and computational fluid dynamics modelling. Towards this end, several computer models of the aorta of a patient presenting with an acute Stanford type B dissection were created whereby morphometric parameters related to the dissection septum were altered, such as removal of the septum, and the variation of the number of connecting tears between the lumina. Patient-specific flow data acquired using 2D PC-MRI in the ascending aorta were used to set the inflow boundary condition. Coupled zero-dimensional (Windkessel) models representing the distal vasculature were used to define the outlet boundary conditions and tuned to match 2D PC-MRI flow data acquired in the descending aorta. Haemodynamics in the dissected aorta were compared to those in an equivalent ‘healthy aorta’, created by virtually removing the intimal flap (septum). Local regions of increased velocity, pressure, wall shear stress and alterations in flow distribution were noted, particularly in the narrow true lumen and around the primary entry tear. The computed flow patterns compared favourably with those obtained using 4D PC-MRI. A lumped-parameter heart model was subsequently used to show that in this case there was an estimated 14 % increase in left ventricular stroke work with the onset of dissection. Finally, the effect of secondary connecting tears (i.e. those excluding the primary entry and exit tears) was also studied, revealing significant haemodynamic changes when no secondary tears are included in the model, particularly in the true lumen where increases in flow over \documentclass[12pt]{minimal}
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\begin{document}$$+200\,\%$$\end{document}+200% and drops in peak pressure of 18 % were observed.
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Affiliation(s)
| | - Alia Noorani
- Department of Biomedical Engineering, King's College London, London, SE1 7EH, UK
| | - David Nordsletten
- Department of Biomedical Engineering, King's College London, London, SE1 7EH, UK
| | - C Alberto Figueroa
- Department of Biomedical Engineering, King's College London, London, SE1 7EH, UK. .,Departments of Surgery and Biomedical Engineering, University of Michigan, North Campus Research Complex B20-211W, Ann Arbor, MI, 48109, USA.
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Szeberin Z, Dósa E, Fehérvári M, Csobay-Novák C, Pintér N, Entz L. Early and Long-term Outcome after Open Surgical Suprarenal Aortic Fenestration in Patients with Complicated Acute Type B Aortic Dissection. Eur J Vasc Endovasc Surg 2015; 50:44-50. [DOI: 10.1016/j.ejvs.2014.12.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 12/22/2014] [Indexed: 12/14/2022]
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16
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Song SW, Kim TH, Lim SH, Lee KH, Yoo KJ, Cho BK. Prognostic factors for aorta remodeling after thoracic endovascular aortic repair of complicated chronic DeBakey IIIb aneurysms. J Thorac Cardiovasc Surg 2014; 148:925-32, 933.e1; discussion 932-3. [DOI: 10.1016/j.jtcvs.2014.05.040] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 05/08/2014] [Accepted: 05/16/2014] [Indexed: 01/09/2023]
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17
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Kruse MJ, Fishman EK, Zimmerman SL. Characterization of Aortic Dissection: What the Radiologist Needs to Know. CURRENT CARDIOVASCULAR IMAGING REPORTS 2014. [DOI: 10.1007/s12410-014-9273-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Bing F, Rodière M, Martinelli T, Monnin-Bares V, Chavanon O, Bach V, Baguet JP, Ferretti GR, Thony F. Type A Acute Aortic Dissection. Vasc Endovascular Surg 2014; 48:239-45. [DOI: 10.1177/1538574413518611] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Purpose: To understand why the false channel (FC) remains patent after surgery of type A acute aortic dissection (TAAAD). Materials and Methods: Postoperative contrast-enhanced computed tomography scans of 129 patients operated for TAAAD were analyzed, and a color-Doppler ultrasound examination (CDUS) of the supra-aortic vessels (SAVs) was performed in 12 patients. Results: The FC remained patent in 107 (82.9%) patients. The entry site was situated near the distal anastomosis in 43 (40.2%) patients and far from it in 44 (41.1%) patients. In 10 (9.35%) patients, an entry site was observed only in the SAVs. In 10 (9.35%) patients, no entry site was seen. Of the 12 patients explored with CDUS, a retrograde filling of the FC was observed in 11 patients. Conclusion: The frequent postoperative circulating aortic FC can be explained by the persistence of the primary entry tear, the presence of iatrogenic tears, and/or a retrograde filling in the SAVs.
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Ravichandran P, Harrington DM, Lovell MB, Harris JR, DeRose G, Forbes TL. Patterns of Visceral and Renal Artery Involvement in Type B Aortic Dissections. Vasc Endovascular Surg 2012. [DOI: 10.1177/1538574412467863] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Objective: The main objective of this study was to describe the visceral and renal vessel involvement and the outcomes in thoracic dissections. Methods: Computed tomography scans of 39 patients were reviewed (30 type B, 9 type A). Visceral and renal arteries were recorded as perfused by the true lumen (TL) or false lumen (FL). Radiologic follow-up was 3.3 years (range 0-10). Results: A total of 156 vessels were analyzed, and 49 (31%) were supplied by the FL. The most common patterns were FL supply of a renal artery (RA) with the visceral arteries and contralateral RA from the TL. In the follow-up, branch vessel compromise occurred in 12 vessels and was more likely to occur when supplied by the FL ( P = .01). About 75% of the patients with at least 2 vessels supplied by the FL demonstrated aortic dilatation. Conclusions: Branch vessel occlusion is more likely in the vessels supplied by the FL. Aortic dilatation occurred more frequently when 2 or more vessels were supplied by the FL.
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Affiliation(s)
- Pranavi Ravichandran
- Division of Vascular Surgery, London Health Sciences Centre & Western University, London, ON, Canada
| | - David M. Harrington
- Division of Vascular Surgery, London Health Sciences Centre & Western University, London, ON, Canada
| | - Marge B. Lovell
- Division of Vascular Surgery, London Health Sciences Centre & Western University, London, ON, Canada
| | - Jeremy R. Harris
- Division of Vascular Surgery, London Health Sciences Centre & Western University, London, ON, Canada
| | - Guy DeRose
- Division of Vascular Surgery, London Health Sciences Centre & Western University, London, ON, Canada
| | - Thomas L. Forbes
- Division of Vascular Surgery, London Health Sciences Centre & Western University, London, ON, Canada
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Qin YL, Deng G, Li TX, Jing RW, Teng GJ. Risk factors of incomplete thrombosis in the false lumen after endovascular treatment of extensive acute type B aortic dissection. J Vasc Surg 2012; 56:1232-8. [DOI: 10.1016/j.jvs.2012.04.019] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2011] [Revised: 03/09/2012] [Accepted: 04/08/2012] [Indexed: 11/25/2022]
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Humphrey JD. Possible mechanical roles of glycosaminoglycans in thoracic aortic dissection and associations with dysregulated transforming growth factor-β. J Vasc Res 2012; 50:1-10. [PMID: 23018968 DOI: 10.1159/000342436] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Accepted: 07/25/2012] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Four distinguishing histopathological characteristics of thoracic aortic aneurysms and dissections (TAADs) are the fragmentation or degradation of elastic fibers, loss of smooth muscle, pooling of glycosaminoglycans, and remodeling of fibrillar collagens. Of these, pooling of glycosaminoglycans appears to be unique to these lesions. METHODS This review acknowledges the importance of dysregulated transforming growth factor-β (TGF-β) in TAADs and offers a complementary hypothesis that increased TGF-β could contribute to the accumulation of glycosaminoglycans in the media of the proximal thoracic aorta. Regardless, observed pools of glycosaminoglycans could decrease tensile strength, cause stress concentrations, and increase intralamellar swelling pressure, all of which could initiate local delaminations that could subsequently propagate as dissections and result in a false lumen or rupture. CONCLUSIONS There is a pressing need to investigate potential mechanical as well as biological consequences of accumulated glycosaminoglycans in TAADs and to elucidate responsible signaling pathways, with particular attention to synthetic cells of nonmesodermal lineage. Such research could provide insight into the mechanisms of dissection and the seemingly paradoxical role of the over-expression of a cytokine that is typically associated with fibrosis but is implicated in a degenerative disease of the aorta that can result in a catastrophic mechanical failure.
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Affiliation(s)
- J D Humphrey
- Department of Biomedical Engineering, Yale University, and Vascular Biology and Therapeutics Program, Yale School of Medicine, New Haven, CT 06520, USA.
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Stanley GA, Murphy EH, Knowles M, Ilves M, Jessen ME, Dimaio JM, Modrall JG, Arko FR. Volumetric analysis of type B aortic dissections treated with thoracic endovascular aortic repair. J Vasc Surg 2011; 54:985-92; discussion 992. [PMID: 21917398 DOI: 10.1016/j.jvs.2011.03.263] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2011] [Revised: 03/15/2011] [Accepted: 03/15/2011] [Indexed: 12/11/2022]
Abstract
BACKGROUND Type B aortic dissections are being successfully treated by thoracic endovascular aortic repair (TEVAR). Postoperative false lumen patency has been associated with aneurysmal dilatation and rupture of the thoracic aorta, necessitating further intervention. This is the first volumetric analysis of type B aortic dissections comparing patients with and without false lumen thrombosis (FLT) after TEVAR. We hypothesized that a greater increase in postoperative true lumen volume will lead to FLT, and without this change, false lumen patency will result. METHODS Preoperative and postoperative computed tomography angiography (CTA) imaging was analyzed using three-dimensional reconstruction to measure the short- and long-axis diameter and cross-sectional area of the true lumen, false lumen, and total aorta. Measurements were taken at 5-cm intervals from the left subclavian artery to the aortic bifurcation. Pre- and postoperative volumetric data were calculated and compared in patients with and without postoperative FLT. RESULTS Between 2006 and 2010, 132 patients underwent thoracic aortic stent grafting. Of these, 31 (23%) had thoracic endografting for type B aortic dissection. Pre- and postoperative CTA images were available for analysis in 23 patients with a mean age of 59 ± 14 years treated for acute, complicated (n = 8, 35%), and chronic (n = 15, 65%) indications. Mean follow-up imaging was 9 months (range, 1-39 months). Thirteen patients (56%) had postoperative FLT and 10 (43%) had persistent false lumen patency. The dissections involved the left subclavian artery (n = 12), visceral arteries (n = 14), renal arteries (n = 16), and iliac arteries (n = 15). The left subclavian artery was intentionally covered in 15 patients (65%). There were no significant differences in age, acute vs chronic dissection, branch vessel involvement, coverage of the left subclavian artery, or distal extent of the endograft between patients with and without postoperative FLT. Patients with postoperative FLT had a significantly smaller preoperative maximum thoracic aortic diameter (5.05 ± 1.0 vs 6.30 ± 1.4 cm; P = .02). Volumetric analysis demonstrated significantly smaller preoperative true lumen volume (141.3 ± 68 vs 230.5 ± 92 cm(3); P = .01) in patients with FLT, but no difference in preoperative false lumen volume. Patients with FLT had a significant increase in the volume percentage of the true lumen from 42.7% to 61.7% (P = .02) after stent graft repair, compared with an increase from 46.7% to 47.7% (P = .75) in patients with persistent false lumen patency. CONCLUSIONS This volumetric study of type B aortic dissection treated with TEVAR suggests that the ability of the endograft to significantly increase the true lumen volume as a percent of the total aorta most accurately predicts postoperative FLT. This is best demonstrated in a nonaneurysmal dissection regardless of timing since dissection.
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Affiliation(s)
- Gregory A Stanley
- Division of Vascular and Endovascular Surgery, University of Texas Southwestern Medical Center, Dallas, TX, USA
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