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Pei Y, Liu Q, Li X. Haemodynamic study of left nonthrombotic iliac vein lesions: a preliminary report. Sci Rep 2024; 14:18837. [PMID: 39138303 PMCID: PMC11322632 DOI: 10.1038/s41598-024-69598-8] [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: 04/06/2024] [Accepted: 08/07/2024] [Indexed: 08/15/2024] Open
Abstract
Nonthrombotic iliac vein lesions (NIVLs) are significant causes of chronic venous insufficiency (CVI) in the left lower limb and symptom recurrence following left lower limb varicose vein treatment. The goal of this study was to explore the haemodynamic and morphological characteristics of iliac veins in patients with NIVLs. Pressure at the caudal end of the stenotic left common iliac vein (LCIV) segment, local blood flow velocity, and time-averaged wall shear stress in the stenotic segment exhibited positive correlations with the clinical CVI classification (R = 0.92, p < 0.001; R = 0.94, p < 0.001; R = 0.87, p < 0.001), while the relative retention time showed a negative correlation (R = -0.94, p < 0.001). The pressure difference (∆P) between the two ends of the stenotic segment and the velocity difference (∆V) between the stenotic segment and the caudal end were positively correlated with the clinical classification (R = 0.92, p < 0.001; R = 0.9, p < 0.001). The cross-sectional area stenosis rate and length of the stenotic LCIV segment were positively correlated with the clinical classification (R = 0.93, p < 0.001; R = 0.63, p < 0.001). The results suggest that haemodynamic assessment of the iliac vein could effectively portray blood flow disturbances in stenotic segments of the LCIV, potentially reflecting the degree of iliac vein stenosis. Haemodynamic indicators are correlated with the severity of clinical CVI symptoms.
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Affiliation(s)
- Yun Pei
- Department of Interventional Radiology and Vascular Surgery, Peking University Third Hospital, 49 North Huayuan Road, Haidian District, 100191, Beijing, China
| | - Qijia Liu
- Department of Interventional Radiology and Vascular Surgery, Peking University Third Hospital, 49 North Huayuan Road, Haidian District, 100191, Beijing, China
| | - Xuan Li
- Department of Interventional Radiology and Vascular Surgery, Peking University Third Hospital, 49 North Huayuan Road, Haidian District, 100191, Beijing, China.
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Xiong Z, Wang X, Yan Y, Liu Z, Luo X, Zheng T. A streamlined controlled-expansion covered tapered stent for TIPS in the treatment of PHT. J Biomech 2024; 163:111937. [PMID: 38246010 DOI: 10.1016/j.jbiomech.2024.111937] [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: 10/09/2023] [Revised: 12/17/2023] [Accepted: 01/04/2024] [Indexed: 01/23/2024]
Abstract
Transjugular intrahepatic portosystemic shunt (TIPS) relieves cirrhotic complications by reducing portacaval pressure gradient (PCG), but it lacks precision in achieving a targeted post-TIPS PCG simply through diameter adjustment of equal diameter stents. This study aimed to present a controlled-expansion, streamlined, and covered tapered stent, and examined its effects on pressure reduction compared with equal- diameter stents. Twenty-four patients who underwent standardized 8-mm stent TIPS implantation at West China Hospital from December 2017 to February 2021 were included in the current study. Virtual equal-diameter stent graft with different diameter and streamlined tapered stents were created in the post-TIPS 3-dimentional models reconstructed based on computed tomography angiography data. The numerical simulation showed that only two patients achieved targeted post-TIPS PCG consistent with the clinical invasive measurement. When 6-mm and 10-mm equal-diameter stents were employed, simulated post-TIPS PCGs for most patients remained outside the safe range, and recirculating flow was observed at the stent-portal vein anastomosis. In contrast, the use of the new streamlined taper stent resulted in post-TIPS PCGs within the 10-12 mmHg range for 17 out of 24 patients, with no recirculating flow observed at the anastomotic sites. In conclusion, the streamlined tapered stent could pose an effective solution to the problem that the big jump depressurization between two different equal-diameter stents and it would improve the hemodynamics in the region near the PV-stent anchorage. Therefore, the streamlined tapered stent may present a superior alternative for TIPS procedure.
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Affiliation(s)
- Zhuxiang Xiong
- Department of Mechanics & Engineering, College of Architecture & Environment, Sichuan University, Chengdu 610065, China; Sichuan University Yibin Park/Yibin Institute of Industrial Technology, Yibin 644000, China
| | - Xiaoze Wang
- Department of Gastroenterology and Hepatology, West China Hospital, Sichuan University, 37 Guoxue Lane, Chengdu 610041, China
| | - Yuling Yan
- Department of Gastroenterology and Hepatology, West China Hospital, Sichuan University, 37 Guoxue Lane, Chengdu 610041, China
| | - Zhan Liu
- Department of Mechanics & Engineering, College of Architecture & Environment, Sichuan University, Chengdu 610065, China; Sichuan University Yibin Park/Yibin Institute of Industrial Technology, Yibin 644000, China
| | - Xuefeng Luo
- Department of Gastroenterology and Hepatology, West China Hospital, Sichuan University, 37 Guoxue Lane, Chengdu 610041, China
| | - Tinghui Zheng
- Department of Mechanics & Engineering, College of Architecture & Environment, Sichuan University, Chengdu 610065, China; West China Information Center, Sichuan University, Chengdu 610065, China.
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Chaudhuri K, Pletzer A, Smith NP. A predictive patient-specific computational model of coronary artery bypass grafts for potential use by cardiac surgeons to guide selection of graft configurations. Front Cardiovasc Med 2022; 9:953109. [PMID: 36237904 PMCID: PMC9552835 DOI: 10.3389/fcvm.2022.953109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 09/01/2022] [Indexed: 01/09/2023] Open
Abstract
Cardiac surgeons face a significant degree of uncertainty when deciding upon coronary artery bypass graft configurations for patients with coronary artery disease. This leads to significant variation in preferred configuration between different surgeons for a particular patient. Additionally, for the majority of cases, there is no consensus regarding the optimal grafting strategy. This situation results in the tendency for individual surgeons to opt for a “one size fits all” approach and use the same grafting configuration for the majority of their patients neglecting the patient-specific nature of the diseased coronary circulation. Quantitative metrics to assess the adequacy of coronary bypass graft flows have recently been advocated for routine intraoperative use by cardiac surgeons. In this work, a novel patient-specific 1D-0D computational model called “COMCAB” is developed to provide the predictive haemodynamic parameters of functional graft performance that can aid surgeons to avoid configurations with grafts that have poor flow and thus poor patency. This model has significant potential for future expanded applications.
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Affiliation(s)
- Krish Chaudhuri
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
- Green Lane Cardiothoracic Surgical Unit, Auckland City Hospital, Auckland, New Zealand
- *Correspondence: Krish Chaudhuri,
| | | | - Nicolas P. Smith
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD, Australia
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Rezaeimoghaddam M, Oguz GN, Ates MS, Bozkaya TA, Piskin S, Samaneh Lashkarinia S, Tenekecioglu E, Karagoz H, Pekkan K. Patient-Specific Hemodynamics of New Coronary Artery Bypass Configurations. Cardiovasc Eng Technol 2020; 11:663-678. [PMID: 33051831 DOI: 10.1007/s13239-020-00493-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 10/01/2020] [Indexed: 11/25/2022]
Abstract
PURPOSE This study aims to quantify the patient-specific hemodynamics of complex conduit routing configurations of coronary artery bypass grafting (CABG) operation which are specifically suitable for off-pump surgeries. Coronary perfusion efficacy and local hemodynamics of multiple left internal mammary artery (LIMA) with sequential and end-to-side anastomosis are investigated. Using a full anatomical model comprised of aortic arch and coronary artery branches the optimum perfusion configuration in multi-vessel coronary artery stenosis is desired. METHODOLOGY Two clinically relevant CABG configurations are created using a virtual surgical planning tool where for each configuration set, the stenosis level, anastomosis distance and angle were varied. A non-Newtonian computational fluid dynamics solver in OpenFOAM incorporated with resistance boundary conditions representing the coronary perfusion physiology was developed. The numerical accuracy is verified and results agreed well with a validated commercial cardiovascular flow solver and experiments. For segmental performance analysis, new coronary perfusion indices to quantify deviation from the healthy scenario were introduced. RESULTS The first simulation configuration set;-a CABG targeting two stenos sites on the left anterior descending artery (LAD), the LIMA graft was capable of 31 mL/min blood supply for all the parametric cases and uphold the healthy LAD perfusion in agreement with the clinical experience. In the second end-to-side anastomosed graft configuration set;-the radial artery graft anastomosed to LIMA, a maximum of 64 mL/min flow rate in LIMA was observed. However, except LAD, the obtuse marginal (OM) and second marginal artery (m2) suffered poor perfusion. In the first set, average wall shear stress (WSS) were in the range of 4 to 35 dyns/cm2 for in LAD. Nevertheless, for second configuration sets the WSS values were higher as the LIMA could not supply enough blood to OM and m2. CONCLUSION The virtual surgical configurations have the potential to improve the quality of operation by providing quantitative surgical insight. The degree of stenosis is a critical factor in terms of coronary perfusion and WSS. The sequential anastomosis can be done safely if the anastomosis angle is less than 90 degrees regardless of degree of stenosis. The smaller proposed perfusion index value, O(0.04 - 0) × 102, enable us to quantify the post-op hemodynamic performance by comparing with the ideal healthy physiological flow.
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Affiliation(s)
- Mohammad Rezaeimoghaddam
- Department of Mechanical Engineering, Koc University, Rumeli Feneri Campus, Sariyer, Istanbul, Turkey
| | - Gokce Nur Oguz
- Department of Mechanical Engineering, Koc University, Rumeli Feneri Campus, Sariyer, Istanbul, Turkey
| | - Mehmet Sanser Ates
- Department of Cardiovascular Surgery, Koc University Hospital, Topkapi, Istanbul, Turkey
| | - Tijen Alkan Bozkaya
- Department of Cardiovascular Surgery, Koc University Hospital, Topkapi, Istanbul, Turkey
| | - Senol Piskin
- Department of Mechanical Engineering, Istinye University, Zeytinburnu, Istanbul, Turkey
| | - S Samaneh Lashkarinia
- Department of Mechanical Engineering, Koc University, Rumeli Feneri Campus, Sariyer, Istanbul, Turkey
| | - Erhan Tenekecioglu
- Department of Cardiology, Health Sciences University, Bursa Education and Research Hospital, Bursa, Turkey
| | - Haldun Karagoz
- Department of Cardiovascular Surgery, VKV American Hospital, Istanbul, Turkey
| | - Kerem Pekkan
- Department of Mechanical Engineering, Koc University, Rumeli Feneri Campus, Sariyer, Istanbul, Turkey.
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Lee KE, Lee SH, Shin ES, Shim EB. A vessel length-based method to compute coronary fractional flow reserve from optical coherence tomography images. Biomed Eng Online 2017. [PMID: 28651585 PMCID: PMC5485716 DOI: 10.1186/s12938-017-0365-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Background Hemodynamic simulation for quantifying fractional flow reserve (FFR) is often performed in a patient-specific geometry of coronary arteries reconstructed from the images from various imaging modalities. Because optical coherence tomography (OCT) images can provide more precise vascular lumen geometry, regardless of stenotic severity, hemodynamic simulation based on OCT images may be effective. The aim of this study is to perform OCT–FFR simulations by coupling a 3D CFD model from geometrically correct OCT images with a LPM based on vessel lengths extracted from CAG data with clinical validations for the present method. Methods To simulate coronary hemodynamics, we developed a fast and accurate method that combined a computational fluid dynamics (CFD) model of an OCT-based region of interest (ROI) with a lumped parameter model (LPM) of the coronary microvasculature and veins. Here, the LPM was based on vessel lengths extracted from coronary X-ray angiography (CAG) images. Based on a vessel length-based approach, we describe a theoretical formulation for the total resistance of the LPM from a three-dimensional (3D) CFD model of the ROI. Results To show the utility of this method, we present calculated examples of FFR from OCT images. To validate the OCT-based FFR calculation (OCT–FFR) clinically, we compared the computed OCT–FFR values for 17 vessels of 13 patients with clinically measured FFR (M-FFR) values. Conclusion A novel formulation for the total resistance of LPM is introduced to accurately simulate a 3D CFD model of the ROI. The simulated FFR values compared well with clinically measured ones, showing the accuracy of the method. Moreover, the present method is fast in terms of computational time, enabling clinicians to provide solutions handled within the hospital.
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Affiliation(s)
- Kyung Eun Lee
- Department of Mechanical and Biomedical Engineering, Kangwon National University, Kangwondaehak-gil, Chuncheon-si, Kangwon-do, 200-701, Republic of Korea
| | - Seo Ho Lee
- Department of Mechanical and Biomedical Engineering, Kangwon National University, Kangwondaehak-gil, Chuncheon-si, Kangwon-do, 200-701, Republic of Korea
| | - Eun-Seok Shin
- Department of Cardiology, University of Ulsan College of Medicine, Ulsan, South Korea
| | - Eun Bo Shim
- Department of Mechanical and Biomedical Engineering, Kangwon National University, Kangwondaehak-gil, Chuncheon-si, Kangwon-do, 200-701, Republic of Korea.
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Tang D, Li ZY. Preface: Computational and experimental methods for biological research: cardiovascular diseases and beyond. Biomed Eng Online 2016; 15:157. [PMID: 28155696 PMCID: PMC5259905 DOI: 10.1186/s12938-016-0269-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- Dalin Tang
- School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096 China
- Department of Mathematical Sciences, Worcester Polytechnic Institute, Worcester, MA 01609 USA
| | - Zhi-Yong Li
- School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096 China
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