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Mutlu O, Saribay M, Yavuz MM, Salman HE, Al-Nabti ARDMH, Yalcin HC. Material modeling and recent findings in transcatheter aortic valve implantation simulations. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2024; 255:108314. [PMID: 39024970 DOI: 10.1016/j.cmpb.2024.108314] [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: 03/11/2024] [Revised: 06/12/2024] [Accepted: 06/28/2024] [Indexed: 07/20/2024]
Abstract
BACKGROUND AND OBJECTIVE Transcatheter aortic valve implantation (TAVI) has significantly transformed the management of aortic valve (AV) diseases, presenting a minimally invasive option compared to traditional surgical valve replacement. Computational simulations of TAVI become more popular and offer a detailed investigation by employing patient-specific models. On the other hand, employing accurate material modeling procedures and applying basic modeling steps are crucial to determining reliable numerical results. Therefore, this review aims to outline the basic modeling approaches for TAVI, focusing on material modeling and geometry extraction, as well as summarizing the important findings from recent computational studies to guide future research in the field. METHODS This paper explains the basic steps and important points in setting up and running TAVI simulations. The material properties of the leaflets, valves, stents, and tissues utilized in TAVI simulations are provided, along with a comprehensive explanation of the geometric extraction methods employed. The differences between the finite element analysis, computational fluid dynamics, and fluid-structure interaction approaches are pointed out and the important aspects of TAVI modeling are described by elucidating the recent computational studies. RESULTS The results of the recent findings on TAVI simulations are summarized to demonstrate its powerful potential. It is observed that the material properties of aortic tissues and components of implanted valves should be modeled realistically to determine accurate results. For patient-specific AV geometries, incorporating calcific deposits on the leaflets is essential for ensuring the accuracy of computational findings. The results of numerical TAVI simulations indicate the significance of the selection of optimal valves and precise deployment within the appropriate anatomical position. These factors collectively contribute to the effective functionality of the implanted valve. CONCLUSIONS Recent studies in the literature have revealed the critical importance of patient-specific modeling, the selection of accurate material models, and bio-prosthetic valve diameters. Additionally, these studies emphasize the necessity of precise positioning of bio-prosthetic valves to achieve optimal performance in TAVI, characterized by an increased effective orifice area and minimal paravalvular leakage.
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Affiliation(s)
- Onur Mutlu
- Qatar University, Biomedical Research Center, Doha, Qatar
| | - Murat Saribay
- Istanbul Bilgi University, Mechanical Engineering Department, Istanbul, Turkey
| | - Mehmet Metin Yavuz
- Middle East Technical University, Mechanical Engineering Department, Ankara, Turkey
| | - Huseyin Enes Salman
- TOBB University of Economics and Technology, Department of Mechanical Engineering, Ankara, Turkey
| | | | - Huseyin Cagatay Yalcin
- Qatar University, Biomedical Research Center, Doha, Qatar; Department of Biomedical Science, College of Health Sciences, QU Health, Qatar University, Doha, Qatar.
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Liu M, Liu J, Yu W, Gao X, Chen S, Qin W, Zhu Z, Li C, Li F, Zhai Z. Clinical and radiological features associated with rupture of pulmonary artery pseudoaneurysm: a retrospective study. BMC Pulm Med 2024; 24:417. [PMID: 39198796 PMCID: PMC11351075 DOI: 10.1186/s12890-024-03225-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Accepted: 08/16/2024] [Indexed: 09/01/2024] Open
Abstract
BACKGROUND Hemoptysis resulting from rupture of the pulmonary artery pseudoaneurysm (PAP) is massive and fatal, while factor contributing to the rupture of pseudoaneurysm remains elusive. This study aimed to elucidate the clinical and radiological features of PAP and identify the risk factors associated with rupture. METHODS Patients who developed hemoptysis with PAP were collected from January 2019 to December 2022 retrospectively. Clinical data of the demographic characteristics, radiological findings, treatment strategies, and prognosis were collected. A comparative analysis was performed on the characteristics in the ruptured and non-ruptured cases. RESULTS A total of 58 PAPs were identified in the 50 patients. The most common causes were infection (86%) and cancer (8%). The PAPs were located predominantly in the upper lobes of both lungs, and 57 (99.3%) were distributed in the segmental or subsegmental pulmonary arteries. The median diameter was 6.1(4.3-8.7) mm. A total of 29 PAPs were identified adjacent to pulmonary cavitations, with the median diameter of the cavity being 18.9 (12.4-34.8) mm. Rupture of pseudoaneurysm occurred in 21 cases (42%). Compared to unruptured group, the ruptured group had a significantly higher proportion of massive hemoptysis (57.1% vs. 6.9%, p < 0.001), larger pseudoaneurysm diameter (8.1 ± 3.2 mm vs. 6.0 ± 2.3 mm, p = 0.012), higher incidence of pulmonary cavitation (76.2% vs. 44.8%, p = 0.027), and larger cavitation diameters (32.9 ± 18.8 mm vs. 15.7 ± 8.4 mm, p = 0.005). The mean pulmonary artery pressure (mPAP) in the ruptured group was also significantly higher than that in the unruptured group [23.9 ± 7.4 mmHg vs. 19.2 ± 5.0 mmHg, p = 0.011]. Endovascular treatment was successfully performed in all 21 patients with ruptured PAP, of which the clinical success rate was 96.0%. Five patients experienced recurrent hemoptysis within one year. CONCLUSIONS Massive hemoptysis, pseudoaneurysm diameter, pulmonary cavitation, and elevated mPAP were the risk factors for rupture of pseudoaneurysm. Our findings facilitate early identification and timely intervention of PAP at high risk of rupture.
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Affiliation(s)
- Min Liu
- National Center for Respiratory Medicine, State Key Laboratory of Respiratory Health and Multimorbidity, National Clinical Research Center for Respiratory Diseases, Institute of Respiratory Medicine, Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, Chinese Academy of Medical Sciences, China-Japan Friendship Hospital, No 2, East Yinghua Road, 100029, Beijing, China
| | - Jixiang Liu
- National Center for Respiratory Medicine, State Key Laboratory of Respiratory Health and Multimorbidity, National Clinical Research Center for Respiratory Diseases, Institute of Respiratory Medicine, Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, Chinese Academy of Medical Sciences, China-Japan Friendship Hospital, No 2, East Yinghua Road, 100029, Beijing, China
| | - Wei Yu
- Department of Pulmonary and Critical Care Medicine, Affiliated Hospital of Jianghan University, No.168 Hongkong Road, 430000, Wuhan, Hubei, China
| | - Xiaoyan Gao
- Department of Pulmonary and Critical Care Medicine, Affiliated Hospital of Jianghan University, No.168 Hongkong Road, 430000, Wuhan, Hubei, China
| | - Shi Chen
- Department of Pulmonary and Critical Care Medicine, Affiliated Hospital of Jianghan University, No.168 Hongkong Road, 430000, Wuhan, Hubei, China
| | - Wei Qin
- Department of Pulmonary and Critical Care Medicine, Affiliated Hospital of Jianghan University, No.168 Hongkong Road, 430000, Wuhan, Hubei, China
| | - Ziyang Zhu
- Department of Pulmonary and Critical Care Medicine, Affiliated Hospital of Jianghan University, No.168 Hongkong Road, 430000, Wuhan, Hubei, China
| | - Chenghong Li
- Department of Pulmonary and Critical Care Medicine, Affiliated Hospital of Jianghan University, No.168 Hongkong Road, 430000, Wuhan, Hubei, China
- Institute of Pulmonary Vascular Diseases, Jianghan University, No.168 Hongkong Road, 430000, Wuhan, Hubei, China
| | - Fajiu Li
- Department of Pulmonary and Critical Care Medicine, Affiliated Hospital of Jianghan University, No.168 Hongkong Road, 430000, Wuhan, Hubei, China.
| | - Zhenguo Zhai
- National Center for Respiratory Medicine, State Key Laboratory of Respiratory Health and Multimorbidity, National Clinical Research Center for Respiratory Diseases, Institute of Respiratory Medicine, Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, Chinese Academy of Medical Sciences, China-Japan Friendship Hospital, No 2, East Yinghua Road, 100029, Beijing, China.
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Li L, Wang Y, Jin P, Yang T, Zhu G, Li Y, Tang J, Liu Y, Yang J. Hemodynamics in the treatment of pseudoaneurysm caused by extreme constriction of aortic arch with coated stent. Front Cardiovasc Med 2024; 11:1363230. [PMID: 39228660 PMCID: PMC11368758 DOI: 10.3389/fcvm.2024.1363230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Accepted: 06/24/2024] [Indexed: 09/05/2024] Open
Abstract
Objectives To evaluate the changes in distal vascular morphology and hemodynamics in patients with extremely severe aortic coarctation (CoA) after covered palliative (CP) stent dilation with different surgical strategies. Materials and methods Perioperative computed tomography angiography and digital subtraction angiography were utilized to construct three aortic models with varying stenosis rates and one follow-up model in a patient with extremely severe CoA. The models included: an idealized non-stenosed model (A: 0%), a model post initial stent deployment (B: 28%), a model post balloon expansion (C: 39%), and a model 18 months after post-balloon expansion (D: 39%). Consistent boundary conditions were applied to all models, and hemodynamic simulation was conducted using the pure fluid method. Results The narrowest and distal diameter of the stent increased by 34.71% and 59.29%, respectively, from model B to C. Additionally, the distal diameter of the stent increased by -13.80% and +43.68% compared to the descending aorta diameter, respectively. Furthermore, the ellipticity of the maximum cross-section of the aneurysm region in model A to D continued to increase. The oscillatory shear index at the stenosis to the region of the aneurysm were found to be higher in Models A and B, and lower in Models C and D. At the moment of maximum flow velocity, the blood flow distribution in models A and B was more uniform in the widest section of the blood vessels at the distal end of the stenosis, whereas models C and D exhibited disturbed blood flow with more than 2 eddy currents. The time-averaged wall shear stress (TAWSS) decreased in the distal and basal aneurysms, while it significantly increased at the step position. The aneurysmal region exhibited an endothelial cell activation potential value lower than 0.4 Pa-1. Conclusion In patients with extremely severe CoA, it is crucial to ensure that the expanded diameter at both ends of the CP stent does not exceed the native vascular diameter during deployment. Our simulation results demonstrate that overdilation leads to a decrease in the TAWSS above the injured vessel, creating an abnormal hemodynamic environment that may contribute to the development and enlargement of false aneurysms in the early postoperative period. Clinical Trial Registration ClinicalTrials.gov, (NCT02917980).
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Affiliation(s)
- Lanlan Li
- Department of Cardiovascular Surgery, Xijing Hospital, Air Force Medical University, Xi’an, Shaanxi, China
| | - Yiwei Wang
- Department of Cardiovascular Surgery, Xijing Hospital, Air Force Medical University, Xi’an, Shaanxi, China
| | - Ping Jin
- Department of Cardiovascular Surgery, Xijing Hospital, Air Force Medical University, Xi’an, Shaanxi, China
| | - Tingting Yang
- School of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi, China
| | - Guangyu Zhu
- School of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi, China
| | - Yuxi Li
- Department of Ultrasound Medicine, Xijing Hospital, Air Force Medical University, Xi’an, Shaanxi, China
| | - Jiayou Tang
- Department of Cardiovascular Surgery, Xijing Hospital, Air Force Medical University, Xi’an, Shaanxi, China
| | - Yang Liu
- Department of Cardiovascular Surgery, Xijing Hospital, Air Force Medical University, Xi’an, Shaanxi, China
| | - Jian Yang
- Department of Cardiovascular Surgery, Xijing Hospital, Air Force Medical University, Xi’an, Shaanxi, China
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Wang Y, Zhou C, Wu X, Liu L, Deng L. Haemodynamic effects of non-Newtonian fluid blood on the abdominal aorta before and after double tear rupture. Med Eng Phys 2024; 130:104205. [PMID: 39160029 DOI: 10.1016/j.medengphy.2024.104205] [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] [Received: 12/14/2023] [Revised: 04/30/2024] [Accepted: 07/01/2024] [Indexed: 08/21/2024]
Abstract
OBJECTIVES Intimal tears caused by aortic dissection can weaken the arterial wall and lead to aortic aneurysms. However, the effect of different tear states on the blood flow behaviour remains complex. This study uses a novel approach that combines numerical haemodynamic simulation with in vitro experiments to elucidate the effect of arterial dissection rupture on the complex blood flow state within the abdominal aneurysm and the endogenous causes of end-organ malperfusion. MATERIALS AND METHODS Based on the CT imaging data and clinical physiological parameters, the overall arterial models including aortic dissection and aneurysm with single tear and double tear were established, and the turbulence behaviours and haemodynamic characteristics of arterial dissection and aneurysm under different blood pressures were simulated by using non-Newtonian flow fluids with the pulsatile blood flow rate of the clinical patients as a cycle, and the results of the numerical simulation were verified by in vitro simulation experiments. RESULTS Hemodynamic simulations revealed that the aneurysm and single-tear false lumen generated a maximum pressure of 320.591 mmHg, 267 % over the 120 mmHg criterion. The pressure differential generates reflux, leading to a WSS of 2247.9 Pa at the TL inlet and blood flow velocities of up to 6.41 m/s inducing extend of the inlet. DTD Medium FL instantaneous WP above 120 mmHg Standard 151 % Additionally, there was 82.5 % higher flow in the right iliac aorta than in the left iliac aorta, which triggered malperfusion. Thrombus was accumulated distal to the tear and turbulence. These results are consistent with the findings of the in vitro experiments. CONCLUSIONS This study reveals the haemodynamic mechanisms by which aortic dissection induces aortic aneurysms to produce different risk states. This will contribute to in vitro simulation studies as a new fulcrum in the process of moving from numerical simulation to clinical trials.
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Affiliation(s)
- Yiwen Wang
- Key Laboratory of Advanced Manufacturing and Intelligent Technology, Ministry of Education, Harbin University of Science and Technology, Harbin, 150080, China.
| | - Changli Zhou
- Key Laboratory of Advanced Manufacturing and Intelligent Technology, Ministry of Education, Harbin University of Science and Technology, Harbin, 150080, China
| | - Xuefeng Wu
- Key Laboratory of Advanced Manufacturing and Intelligent Technology, Ministry of Education, Harbin University of Science and Technology, Harbin, 150080, China
| | - Lijia Liu
- Key Laboratory of Advanced Manufacturing and Intelligent Technology, Ministry of Education, Harbin University of Science and Technology, Harbin, 150080, China
| | - Li Deng
- Department of Cardiovascular Surgery, First Affiliated Hospital of Harbin Medical University, Harbin, 150086, China
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Cheng CF, Shen W. Clinical value identification of RDW on in-hospital death in unruptured abdominal aortic aneurysm. Medicine (Baltimore) 2024; 103:e38822. [PMID: 38968460 PMCID: PMC11224854 DOI: 10.1097/md.0000000000038822] [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: 02/05/2024] [Accepted: 06/13/2024] [Indexed: 07/07/2024] Open
Abstract
This study aimed to identify highly valuable blood indicators for predicting the clinical outcomes of patients with aortic aneurysms (AA). Baseline data of 1180 patients and 16 blood indicators were obtained from the public Medical Information Mart for Intensive Care-IV (MIMIC-IV) database. The association of blood indicators with 4 types of clinical outcomes was analyzed, and the prediction performance of core indicators on different outcomes was next evaluated. Then, we explored the detailed association between core indicators and key outcomes among subgroups. Finally, a machine learning model was established to improve the prediction performance. Generalized linear regression analysis indicated that only red cell volume distribution width (RDW) was commonly associated with 4 end-points including surgery requirement, ICU stay requirement, length of hospital stay, and in-hospital death (all P < .05). Further, RDW showed the best performance for predicting in-hospital death by receiver operating characteristic (ROC) analysis. The significant association between RDW and in-hospital death was then determined by 3 logistic regression models adjusting for different variables (all P < .05). Stratification analysis showed that their association was mainly observed in unruptured AA and abdominal AA (AAA, all P < .05). We subsequently established an RDW-based model for predicting the in-hospital death only in patients with unruptured AAA. The favorable prediction performance of the RDW-based model was verified in training, validation, and test sets. RDW was found to make the greatest contribution to in-hospital death within the model. RDW had favorable clinical value for predicting the in-hospital death of patients, especially in unruptured AAA.
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Affiliation(s)
- Chun-Fa Cheng
- Vascular Hernia Surgery, The First People’s Hospital of Linping District, Hangzhou, Zhejiang, China
| | - Wei Shen
- Vascular Hernia Surgery, The First People’s Hospital of Linping District, Hangzhou, Zhejiang, China
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Pantoja JL, Shehadeh TS, Lee MM, Eldredge JD, Kiang SC. Geometrical Factors Affect Wall Shear Stress in Saccular Aneurysms of the Infrarenal Abdominal Aorta. Ann Vasc Surg 2024; 108:76-83. [PMID: 38942368 DOI: 10.1016/j.avsg.2024.04.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 04/06/2024] [Indexed: 06/30/2024]
Abstract
BACKGROUND Low wall shear stress (WSS) is predictive of aortic aneurysm growth and rupture. Yet, estimating WSS in a clinical setting is impractical, whereas measuring aneurysm geometry is feasible. This study investigates the association between saccular aneurysm geometry of the infrarenal aorta and WSS. METHODS Starting with a nonaneurysmal, patient-specific, computational fluid dynamics model of the aorta, saccular aneurysms of varying geometry were created by incrementally increasing the neck width and sac depth from 1 cm to 4 cm. The aspect ratio (the ratio between sac depth and neck width) varied between 0.25 and 4. The peak WSS, time-averaged WSS (TAWSS), and oscillatory shear index (OSI) were measured within the aneurysm sac. RESULTS Decreasing the neck width from 4 cm to 1 cm decreased the peak WSS by 69% and the TAWSS by 83%. Increasing the sac depth from 1 cm to 4 cm decreased the peak WSS by 55% and the OSI by 37%. The aspect ratio was negatively correlated to peak WSS (Rs -0.85; P < 0.001). CONCLUSIONS In saccular aneurysms of the infrarenal aorta, a smaller neck width, deeper aneurysm sac, and larger aspect ratio are associated with lower peak WSS.
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Affiliation(s)
- Joe Luis Pantoja
- Division of Vascular Surgery, VA Loma Linda Healthcare System, Loma Linda, CA.
| | - Thaer S Shehadeh
- Division of Vascular Surgery, VA Loma Linda Healthcare System, Loma Linda, CA
| | - Mary M Lee
- Division of Vascular Surgery, VA Loma Linda Healthcare System, Loma Linda, CA
| | - Jeffrey D Eldredge
- Department of Mechanical & Aerospace Engineering, University of California, Los Angeles, CA
| | - Sharon C Kiang
- Division of Vascular Surgery, VA Loma Linda Healthcare System, Loma Linda, CA
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Mei J, Yuan Y, Yan H, Zhao X, Xue T, Su H, Jia Z. Factors associated with false lumen changes in patients with superior mesenteric artery dissection. Vasc Med 2024; 29:274-285. [PMID: 38334057 DOI: 10.1177/1358863x231220624] [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: 02/10/2024]
Abstract
BACKGROUND False lumen changes (FLCs) are the main reference for the prognosis judgment and treatment plan selection for type IIa superior mesenteric artery dissection (SMAD). METHODS For this retrospective study, 55 patients with symptomatic type IIa SMAD were included. Computational fluid dynamics (CFD) analysis was used to explore the hemodynamic basis of FLCs. Correlation and multiple linear regression analyses were performed to identify clinical, morphological and hemodynamic factors associated with FLCs. RESULTS The FLCs of patients with successful conservative treatment (n = 29) are significantly higher than those with failed conservative treatment (n = 26) (58.5 ± 21.1% vs 10.9 ± 17.4%, p < 0.0001). Positive correlations were seen between FLCs and the morphological parameters false lumen length (FLL)/dissection entrance length (DEL) and FLL. In terms of hemodynamic parameters, negative correlations were seen between FLCs and time-averaged wall shear stress (TAWSS), vorticity, and high areas of TAWSS and vorticity, whereas positive correlations were seen between FLCs and oscillatory shear index (OSI), relative residence time (RRT), and high areas of OSI and RRT. Multiple linear regression analysis identified symptom duration (odds ratio [OR], 0.93; 95% CI, 0.91-0.96; p < 0.0001), FLL/DEL (OR, 1.30; 95% CI, 1.01-1.67; p = 0.044), and high RRT area (OR, 2.03; 95% CI, 1.48-2.78; p < 0.0001) as predictors of FLCs. CONCLUSION The clinical predictor symptom duration, morphological factor FLL/DEL, and the hemodynamic factor high RRT area can serve as predictors of FLCs in patients with symptomatic type IIa SMAD.
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Affiliation(s)
- Junhao Mei
- Department of Interventional and Vascular Surgery, The Affiliated Changzhou Second People's Hospital of Nanjing Medical University, Changzhou, China
| | - Yuan Yuan
- Department of Interventional Radiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Hui Yan
- Department of Radiology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Xi Zhao
- Central Research Institute, United Imaging Healthcare, Shanghai, China
| | - Tongqing Xue
- Department of Interventional Radiology, Huaian Hospital of Huaian's City, Huai'an, China
| | - Haobo Su
- Department of Interventional Radiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Zhongzhi Jia
- Department of Interventional and Vascular Surgery, The Affiliated Changzhou Second People's Hospital of Nanjing Medical University, Changzhou, China
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Bhargav VN, Francescato N, Mettelsiefen H, Usmani AY, Scarsoglio S, Raghav V. Spatio-temporal Relationship between Three-Dimensional Deformations of a Collapsible Tube and the Downstream Flowfield. JOURNAL OF FLUIDS AND STRUCTURES 2024; 127:104122. [PMID: 39184241 PMCID: PMC11340656 DOI: 10.1016/j.jfluidstructs.2024.104122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/27/2024]
Abstract
The interactions between fluid flow and structural components of collapsible tubes are representative of those in several physiological systems. Although extensively studied, there exists a lack of characterization of the three-dimensionality in the structural deformations of the tube and its influence on the flow field. This experimental study investigates the spatio-temporal relationship between 3D tube geometry and the downstream flow field under conditions of fully open, closed, and slamming-type oscillating regimes. A methodology is implemented to simultaneously measure three-dimensional surface deformations in a collapsible tube and the corresponding downstream flow field. Stereophotogrammetry was used to measure tube deformations, and simultaneous flow field measurements included pressure and planar Particle Image Velocimetry (PIV) data downstream of the collapsible tube. The results indicate that the location of the largest collapse in the tube occurs close to the downstream end of the tube. In the oscillating regime, sections of the tube downstream of the largest mean collapse experience the largest oscillations in the entire tube that are completely coherent and in phase. At a certain streamwise distance upstream of the largest collapse, a switch in the direction of oscillations occurs with respect to those downstream. Physically, when the tube experiences constriction downstream of the location of the largest mean collapse, this causes the accumulation of fluid and build-up of pressure in the upstream regions and an expansion of these sections. Fluctuations in the downstream flow field are significantly influenced by tube fluctuations along the minor axes. The fluctuations in the downstream flowfield are influenced by the propagation of disturbances due to oscillations in tube geometry, through the advection of fluid through the tube. Further, the manifestation of the LU-type pressure fluctuations is found to be due to the variation in the propagation speed of the disturbances during the different stages within a period of oscillation of the tube.
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Affiliation(s)
- Vikas N. Bhargav
- Auburn University, Department of Aerospace Engineering, Auburn, 36849, AL, USA
| | - Nicola Francescato
- Auburn University, Department of Aerospace Engineering, Auburn, 36849, AL, USA
- Politecnico di Torino, Department of Mechanical and Aerospace Engineering, Turin, 10129, Italy
| | - Holger Mettelsiefen
- Auburn University, Department of Aerospace Engineering, Auburn, 36849, AL, USA
| | - Abdullah Y. Usmani
- Auburn University, Department of Aerospace Engineering, Auburn, 36849, AL, USA
| | - Stefania Scarsoglio
- Politecnico di Torino, Department of Mechanical and Aerospace Engineering, Turin, 10129, Italy
| | - Vrishank Raghav
- Auburn University, Department of Aerospace Engineering, Auburn, 36849, AL, USA
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Balasubramanya A, Maes L, Rega F, Mazzi V, Morbiducci U, Famaey N, Degroote J, Segers P. Hemodynamics and wall shear metrics in a pulmonary autograft: Comparing a fluid-structure interaction and computational fluid dynamics approach. Comput Biol Med 2024; 176:108604. [PMID: 38761502 DOI: 10.1016/j.compbiomed.2024.108604] [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] [Received: 01/23/2024] [Revised: 05/02/2024] [Accepted: 05/11/2024] [Indexed: 05/20/2024]
Abstract
OBJECTIVE In young patients, aortic valve disease is often treated by placement of a pulmonary autograft (PA) which adapts to its new environment through growth and remodeling. To better understand the hemodynamic forces acting on the highly distensible PA in the acute phase after surgery, we developed a fluid-structure interaction (FSI) framework and comprehensively compared hemodynamics and wall shear-stress (WSS) metrics with a computational fluid dynamic (CFD) simulation. METHODS The FSI framework couples a prestressed non-linear hyperelastic arterial tissue model with a fluid model using the in-house coupling code CoCoNuT. Geometry, material parameters and boundary conditions are based on in-vivo measurements. Hemodynamics, time-averaged WSS (TAWSS), oscillatory shear index (OSI) and topological shear variation index (TSVI) are evaluated qualitatively and quantitatively for 3 different sheeps. RESULTS Despite systolic-to-diastolic volumetric changes of the PA in the order of 20 %, the point-by-point correlation of TAWSS and OSI obtained through CFD and FSI remains high (r > 0.9, p < 0.01) for TAWSS and (r > 0.8, p < 0.01) for OSI). Instantaneous WSS divergence patterns qualitatively preserve similarities, but large deformations of the PA leads to a decrease of the correlation between FSI and CFD resolved TSVI (r < 0.7, p < 0.01). Moderate co-localization between FSI and CFD is observed for low thresholds of TAWSS and high thresholds of OSI and TSVI. CONCLUSION FSI might be warranted if we were to use the TSVI as a mechano-biological driver for growth and remodeling of PA due to varying intra-vascular flow structures and near wall hemodynamics because of the large expansion of the PA.
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Affiliation(s)
| | - Lauranne Maes
- Department of Mechanical Engineering, KU Leuven, Leuven, Belgium
| | - Filip Rega
- Cardiac Surgery, Department of Cardiovascular Sciences, KU Leuven, Belgium
| | - Valentina Mazzi
- PolitoBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Umberto Morbiducci
- PolitoBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Nele Famaey
- Department of Mechanical Engineering, KU Leuven, Leuven, Belgium
| | - Joris Degroote
- Department of Electromechanical Systems and Metal Engineering, Ghent University, Ghent, Belgium
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Yan Y, An X, Ren H, Luo B, Jin S, Liu L, Di Y, Li T, Huang Y. Nomogram-based geometric and hemodynamic parameters for predicting the growth of small untreated intracranial aneurysms. Neurosurg Rev 2024; 47:169. [PMID: 38635054 DOI: 10.1007/s10143-024-02408-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Revised: 01/30/2024] [Accepted: 04/09/2024] [Indexed: 04/19/2024]
Abstract
Previous studies have shown that the growth status of intracranial aneurysms (IAs) predisposes to rupture. This study aimed to construct a nomogram for predicting the growth of small IAs based on geometric and hemodynamic parameters. We retrospectively collected the baseline and follow-up angiographic images (CTA/ MRA) of 96 small untreated saccular IAs, created patient-specific vascular models and performed computational fluid dynamics (CFD) simulations. Geometric and hemodynamic parameters were calculated. A stepwise Cox proportional hazards regression analysis was employed to construct a nomogram. IAs were stratified into low-, intermediate-, and high-risk groups based on the total points from the nomogram. Receiver operating characteristic (ROC) analysis, calibration curves, decision curve analysis (DCA) and Kaplan-Meier curves were evaluated for internal validation. In total, 30 untreated saccular IAs were grown (31.3%; 95%CI 21.8%-40.7%). The PHASES, ELAPSS, and UIATS performed poorly in distinguishing growth status. Hypertension (hazard ratio [HR] 4.26, 95%CI 1.61-11.28; P = 0.004), nonsphericity index (95%CI 4.10-25.26; P = 0.003), max relative residence time (HR 1.01, 95%CI 1.00-1.01; P = 0.032) were independently related to the growth status. A nomogram was constructed with the above predictors and achieved a satisfactory prediction in the validation cohort. The log-rank test showed significant discrimination among the Kaplan-Meier curves of different risk groups in the training and validation cohorts. A nomogram consisting of geometric and hemodynamic parameters presented an accurate prediction for the growth status of small IAs and achieved risk stratification. It showed higher predictive efficacy than the assessment tools.
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Affiliation(s)
- Yujia Yan
- Tianjin Key Laboratory of Brain Science and Neuroengineering, Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, China
- Haihe Laboratory of Brain-Computer Interaction and Human-Machine Integration, Tianjin, China
- State Key Laboratory of Advanced Medical Materials and Devices, Tianjin University, Tianjin, China
- Department of Neurosurgery, Tianjin Huanhu Hospital, Tianjin, China
| | - Xingwei An
- Tianjin Key Laboratory of Brain Science and Neuroengineering, Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, China
- Haihe Laboratory of Brain-Computer Interaction and Human-Machine Integration, Tianjin, China
- State Key Laboratory of Advanced Medical Materials and Devices, Tianjin University, Tianjin, China
| | - Hecheng Ren
- Department of Neurosurgery, Tianjin Huanhu Hospital, Tianjin, China
| | - Bin Luo
- Department of Neurosurgery, Tianjin Huanhu Hospital, Tianjin, China
| | - Song Jin
- Department of Radiology, Tianjin Huanhu Hospital, Tianjin, China
| | - Li Liu
- Department of Radiology, Tianjin Huanhu Hospital, Tianjin, China
| | - Yang Di
- Tianjin Key Laboratory of Brain Science and Neuroengineering, Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, China
- Haihe Laboratory of Brain-Computer Interaction and Human-Machine Integration, Tianjin, China
- State Key Laboratory of Advanced Medical Materials and Devices, Tianjin University, Tianjin, China
| | - Tingting Li
- Tianjin Key Laboratory of Brain Science and Neuroengineering, Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, China
- Haihe Laboratory of Brain-Computer Interaction and Human-Machine Integration, Tianjin, China
- State Key Laboratory of Advanced Medical Materials and Devices, Tianjin University, Tianjin, China
| | - Ying Huang
- Department of Neurosurgery, Tianjin Huanhu Hospital, Tianjin, China.
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Mei J, Yan H, Zhao X, Yuan Y, Su H, Xue T, Jia Z. In-stent Restenosis After Stenting for Superior Mesenteric Artery Dissection Is Associated With Stent Landing Zone: From Clinical Prediction to Hemodynamic Mechanisms. J Endovasc Ther 2024:15266028241241494. [PMID: 38561992 DOI: 10.1177/15266028241241494] [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: 04/04/2024]
Abstract
OBJECTIVE To identify risk factors for in-stent restenosis (ISR) in patients undergoing stent placement for superior mesenteric artery dissection (SMAD) and to determine the hemodynamic mechanism underlying ISR. METHODS For this retrospective study, patients with SMAD who had ISR after stent placement were included in the ISR group, and age- and sex-matched patients with SMAD who did not experience ISR after stent placement were included in the control group. Clinical, imaging, and hemodynamic data were assessed. Multivariable regression was used to identify independent ISR risk factors. Structural and fluid dynamics simulations were applied to determine the hemodynamic mechanism underlying the occurrence of ISR. RESULTS The study population included 26 patients with ISR and 26 control patients. Multivariate analysis demonstrated that stent-to-vascular (S/V) ratio (odds ratio [OR], 1.14; 95% confidence interval [CI]: 1.00-1.29; p=0.045), stent proximal position >10 mm away from the SMA root (OR, 108.67; 95% CI: 3.09-3816.42; p=0.010), and high oscillatory shear index (OSI) area (OR, 1.25; 95% CI: 1.02-1.52; p=0.029) were predictors of ISR. In structural and fluid dynamics simulations, a stent proximal position near the abdominal aorta (AA) or entering into the AA reduced the contact area between the proximal struts of the stent and the vascular wall, and alleviated the distal lumen overdilation. CONCLUSION The S/V ratio, stent proximal position away from the SMA root (>10 mm), and high OSI area are independent risk factors for ISR in patients with SMAD undergoing stent placement. Deploying the proximal end of the stent near the AA or entering into the AA appears to improve the hemodynamic environment in the SMA lumen and ultimately reduce the risk of ISR. CLINICAL IMPACT In-stent restenosis is an uncommon but potentially catastrophic complication after stent placement for the management of superior mesenteric artery dissection. This study identified risk factors for in-stent restenosis and demonstrated that, as long as the stent can fully cover the dissection range, deploying the proximal end of the stent near the abdominal aorta or less entering into the abdominal aorta may reduce the risk of in-stent restenosis in this patient population.
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Affiliation(s)
- Junhao Mei
- Department of Interventional and Vascular Surgery, The Affiliated Changzhou Second People's Hospital, Nanjing Medical University, Changzhou, China
| | - Hui Yan
- Department of Radiology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Xi Zhao
- Central Research Institute, United Imaging Healthcare, Shanghai, China
| | - Yuan Yuan
- Department of Interventional Radiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Haobo Su
- Department of Interventional Radiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Tongqing Xue
- Department of Interventional Radiology, Huaian Hospital of Huai'an City, Huai'an, China
| | - Zhongzhi Jia
- Department of Interventional and Vascular Surgery, The Affiliated Changzhou Second People's Hospital, Nanjing Medical University, Changzhou, China
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12
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Hasan M, Al-Thani H, El-Menyar A, Zeidan A, Al-Thani A, Yalcin HC. Disturbed hemodynamics and oxidative stress interaction in endothelial dysfunction and AAA progression: Focus on Nrf2 pathway. Int J Cardiol 2023; 389:131238. [PMID: 37536420 DOI: 10.1016/j.ijcard.2023.131238] [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: 02/03/2023] [Revised: 04/30/2023] [Accepted: 07/31/2023] [Indexed: 08/05/2023]
Abstract
Hemodynamic shear stress is one of the major factors that are involved in the pathogenesis of many cardiovascular diseases including atherosclerosis and abdominal aortic aneurysm (AAA), through its modulatory effect on the endothelial cell's redox homeostasis and mechanosensitive gene expression. Among important mechanisms, oxidative stress, endoplasmic reticulum stress activation, and the subsequent endothelial dysfunction are attributed to disturbed blood flow and low shear stress in the vascular curvature and bifurcations which are considered atheroprone regions and aneurysm occurrence spots. Many pathways were shown to be involved in AAA progression. Of particular interest from recent findings is, the (Nrf2)/Keap-1 pathway, where Nrf2 is a transcription factor that has antioxidant properties and is strongly associated with several CVDs, yet, the exact mechanism by which Nrf2 alleviates CVDs still to be elucidated. Nrf2 expression is closely affected by shear stress and was shown to participate in AAA. In the current review paper, we discussed the link between disturbed hemodynamics and its effect on Nrf2 as a mechanosensitive gene and its role in the development of endothelial dysfunction which is linked to the progression of AAA.
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Affiliation(s)
- Maram Hasan
- Biomedical Research Center, Qatar University, P.O. Box 2713, Doha, Qatar
| | - Hassan Al-Thani
- Department of Surgery, Trauma and Vascular Surgery, Hamad General Hospital, Hamad Medical Corporation, P.O. Box 3050, Doha, Qatar
| | - Ayman El-Menyar
- Department of Surgery, Trauma and Vascular Surgery, Hamad General Hospital, Hamad Medical Corporation, P.O. Box 3050, Doha, Qatar; Clinical Medicine, Weill Cornell Medical College, Doha, Qatar
| | - Asad Zeidan
- Department of Basic Sciences, College of Medicine, QU health, Qatar University, P.O. Box 2713, Doha, Qatar
| | - Asmaa Al-Thani
- Biomedical Research Center, Qatar University, P.O. Box 2713, Doha, Qatar; Department of Biomedical Science, College of Health Sciences, QU Health, Qatar University, P.O. Box 2713, Doha, Qatar
| | - Huseyin C Yalcin
- Biomedical Research Center, Qatar University, P.O. Box 2713, Doha, Qatar.
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Deshmukh K, Mitra K, Bit A. Influence of Non-Newtonian Viscosity on Flow Structures and Wall Deformation in Compliant Serpentine Microchannels: A Numerical Study. MICROMACHINES 2023; 14:1661. [PMID: 37763824 PMCID: PMC10536915 DOI: 10.3390/mi14091661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 08/11/2023] [Accepted: 08/23/2023] [Indexed: 09/29/2023]
Abstract
The viscosity of fluid plays a major role in the flow dynamics of microchannels. Viscous drag and shear forces are the primary tractions for microfluidic fluid flow. Capillary blood vessels with a few microns diameter are impacted by the rheology of blood flowing through their conduits. Hence, regenerated capillaries should be able to withstand such impacts. Consequently, there is a need to understand the flow physics of culture media through the lumen of the substrate as it is one of the vital promoting factors for vasculogenesis under optimal shear conditions at the endothelial lining of the regenerated vessel. Simultaneously, considering the diffusive role of capillaries for ion exchange with the surrounding tissue, capillaries have been found to reorient themselves in serpentine form for modulating the flow conditions while developing sustainable shear stress. In the current study, S-shaped (S1) and delta-shaped (S2) serpentine models of capillaries were considered to evaluate the shear stress distribution and the oscillatory shear index (OSI) and relative residual time (RRT) of the derivatives throughout the channel (due to the phenomena of near-wall stress fluctuation), along with the influence of culture media rheology on wall stress parameters. The non-Newtonian power-law formulation was implemented for defining rheological viscosity of the culture media. The flow actuation of the media was considered to be sinusoidal and physiological, realizing the pulsatile blood flow behavior in the circulatory network. A distinct difference in shear stress distributions was observed in both the serpentine models. The S1 model showed higher change in shear stress in comparison to the S2 model. Furthermore, the non-Newtonian viscosity formulation was found to produce more sustainable shear stress near the serpentine walls compared to the Newtonian formulation fluid, emphasizing the influence of rheology on stress generation. Further, cell viability improved in the bending regions of serpentine channels compared to the long run section of the same channel.
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Affiliation(s)
- Khemraj Deshmukh
- Department of Biomedical Engineering, National Institute of Technology, Raipur 492010, India;
| | - Kunal Mitra
- Biomedical Engineering, Florida Tech, Melbourne, FL 32901, USA
| | - Arindam Bit
- Department of Biomedical Engineering, National Institute of Technology, Raipur 492010, India;
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Arslan AC, Salman HE. Effect of Intraluminal Thrombus Burden on the Risk of Abdominal Aortic Aneurysm Rupture. J Cardiovasc Dev Dis 2023; 10:233. [PMID: 37367398 DOI: 10.3390/jcdd10060233] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 05/19/2023] [Accepted: 05/23/2023] [Indexed: 06/28/2023] Open
Abstract
Abdominal aortic aneurysm (AAA) is a critical health disorder, where the abdominal aorta dilates more than 50% of its normal diameter. Enlargement in abdominal aorta alters the hemodynamics and flow-induced forces on the AAA wall. Depending on the flow conditions, the hemodynamic forces on the wall may result in excessive mechanical stresses that lead to AAA rupture. The risk of rupture can be predicted using advanced computational techniques such as computational fluid dynamics (CFD) and fluid-structure interaction (FSI). For a reliable rupture risk assessment, formation of intraluminal thrombus (ILT) and uncertainty in arterial material properties should be taken into account, mainly due to the patient-specific differences and unknowns in AAAs. In this study, AAA models are computationally investigated by performing CFD simulations combined with FSI analysis. Various levels of ILT burdens are artificially generated in a realistic AAA geometry, and the peak effective stresses are evaluated to elucidate the effect of material models and ILT formation. The results indicate that increasing the ILT burden leads to lowered effective stresses on the AAA wall. The material properties of the artery and ILT are also effective on the stresses; however, these effects are limited compared to the effect of ILT volume in the AAA sac.
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Affiliation(s)
- Aykut Can Arslan
- Department of Mechanical Engineering, TOBB University of Economics and Technology, Ankara 06530, Turkey
| | - Huseyin Enes Salman
- Department of Mechanical Engineering, TOBB University of Economics and Technology, Ankara 06530, Turkey
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