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Watson C, Saaid H, Vedula V, Cardenas JC, Henke PK, Nicoud F, Xu XY, Hunt BJ, Manning KB. Venous Thromboembolism: Review of Clinical Challenges, Biology, Assessment, Treatment, and Modeling. Ann Biomed Eng 2024; 52:467-486. [PMID: 37914979 DOI: 10.1007/s10439-023-03390-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 10/17/2023] [Indexed: 11/03/2023]
Abstract
Venous thromboembolism (VTE) is a massive clinical challenge, annually affecting millions of patients globally. VTE is a particularly consequential pathology, as incidence is correlated with extremely common risk factors, and a large cohort of patients experience recurrent VTE after initial intervention. Altered hemodynamics, hypercoagulability, and damaged vascular tissue cause deep-vein thrombosis and pulmonary embolism, the two permutations of VTE. Venous valves have been identified as likely locations for initial blood clot formation, but the exact pathway by which thrombosis occurs in this environment is not entirely clear. Several risk factors are known to increase the likelihood of VTE, particularly those that increase inflammation and coagulability, increase venous resistance, and damage the endothelial lining. While these risk factors are useful as predictive tools, VTE diagnosis prior to presentation of outward symptoms is difficult, chiefly due to challenges in successfully imaging deep-vein thrombi. Clinically, VTE can be managed by anticoagulants or mechanical intervention. Recently, direct oral anticoagulants and catheter-directed thrombolysis have emerged as leading tools in resolution of venous thrombosis. While a satisfactory VTE model has yet to be developed, recent strides have been made in advancing in silico models of venous hemodynamics, hemorheology, fluid-structure interaction, and clot growth. These models are often guided by imaging-informed boundary conditions or inspired by benchtop animal models. These gaps in knowledge are critical targets to address necessary improvements in prediction and diagnosis, clinical management, and VTE experimental and computational models.
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Affiliation(s)
- Connor Watson
- Department of Biomedical Engineering, The Pennsylvania State University, 122 Chemical and Biomedical Engineering Building, University Park, PA, 16802-4400, USA
| | - Hicham Saaid
- Department of Biomedical Engineering, The Pennsylvania State University, 122 Chemical and Biomedical Engineering Building, University Park, PA, 16802-4400, USA
| | - Vijay Vedula
- Department of Mechanical Engineering, Fu Foundation School of Engineering and Applied Science, Columbia University, New York, NY, USA
| | - Jessica C Cardenas
- Department of Surgery and the Center for Translational Injury Research, McGovern Medical School, University of Texas Health Science Center, Houston, TX, USA
| | - Peter K Henke
- Section of Vascular Surgery, Department of Surgery, University of Michigan Health System, Ann Arbor, MI, USA
| | - Franck Nicoud
- CNRS, IMAG, Université de Montpellier, Montpellier, France
- Institut Universitaire de France, Paris, France
| | - Xiao Yun Xu
- Department of Chemical Engineering, Imperial College London, London, UK
| | - Beverley J Hunt
- Department of Thrombosis and Haemostasis, King's College, London, UK
- Thrombosis and Haemophilia Centre, Guy's & St Thomas' NHS Trust, London, UK
| | - Keefe B Manning
- Department of Biomedical Engineering, The Pennsylvania State University, 122 Chemical and Biomedical Engineering Building, University Park, PA, 16802-4400, USA.
- Department of Surgery, Penn State Hershey Medical Center, Hershey, PA, USA.
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Xiong Z, Yan Y, Wang X, Liu Z, Luo X, Zheng T. The effect of splenic vein diameter on the diagnosis of portal vein thrombosis. Med Phys 2023; 50:6614-6623. [PMID: 37227701 DOI: 10.1002/mp.16481] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 04/03/2023] [Accepted: 04/28/2023] [Indexed: 05/26/2023] Open
Abstract
BACKGROUND It was still controversial that whether the increase of splenic vein (SV) diameter increased the risk of portal vein thrombosis (PVT), which was a severe disease with high mortality, in the clinic. PURPOSES This study, using computational fluid dynamics method, aimed to investigate how the increase of SV diameter affects the portal vein hemodynamics under different anatomical and geometric features of the portal venous system, thus how it induced to PVT. METHODS The ideal models of the portal system, including different anatomical structures according to the location of left gastric vein (LGV) and inferior mesenteric vein (IMV), and different geometric morphological parameters models were established to carry out numerical simulation in this study. In addition, the morphological parameters of real patients were measured to verify the numerical simulation results. RESULTS First, the wall shear stress (WSS) and helicity intensity, which were closely related to the occurrence of thrombosis, gradually decreased with the increase of SV diameter in all models. However, the degree of decrease was bigger in following models: (1) the models with LGV and IMV linking to SV compared with them linking to PV; (2) the models with big angle of PV and SV compared with small angle. In addition, the morbidity of PVT was higher when LGV and IMV linked to SV rather than them linked to PV in the real patients. Moreover, the angle of PV and SV was also different between PVT and non-PVT patients (125.53° ± 16.90° vs. 115.03° ± 16.10°, p = 0.01). CONCLUSION Whether the increase of SV diameter will result in PVT is depended on the anatomical structure of portal system and the angle between PV and SV, this is also the reason leading to the clinical controversy that the increase of SV diameter is the risk factor of PVT.
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Affiliation(s)
- Zhuxiang Xiong
- Department of Applied Mechanics, Sichuan University, Chengdu, China
- Sichuan University Yibin Park/Yibin Institute of Industrial Technology, Yibin, China
| | - Yuling Yan
- Department of Gastroenterology and Hepatology, West China Hospital, Sichuan University, Chengdu, China
| | - Xiaoze Wang
- Department of Gastroenterology and Hepatology, West China Hospital, Sichuan University, Chengdu, China
| | - Zhan Liu
- Department of Applied Mechanics, Sichuan University, Chengdu, China
- Sichuan University Yibin Park/Yibin Institute of Industrial Technology, Yibin, China
| | - Xuefeng Luo
- Department of Gastroenterology and Hepatology, West China Hospital, Sichuan University, Chengdu, China
| | - Tinghui Zheng
- Department of Applied Mechanics, Sichuan University, Chengdu, China
- Sichuan University Yibin Park/Yibin Institute of Industrial Technology, Yibin, China
- West China Information Center, Sichuan University, Chengdu, China
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Yan Y, Xiong Z, Wang X, Yang L, Zheng T, Luo X. A novel potential mechanism for the development of portal vein thrombosis in cirrhosis based on portal hemodynamics. Insights Imaging 2022; 13:192. [PMID: 36512292 PMCID: PMC9748017 DOI: 10.1186/s13244-022-01330-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 11/06/2022] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Marked changes in hemodynamics have been suggested to be a potential contributing factor to portal vein thrombosis (PVT) development. This study investigated the effect of portal hemodynamics based on the anatomical structure of the portal venous system on PVT development. METHODS The morphological features of portal venous system in patients with PVT and those without PVT subgroups were compared. In addition, idealized PV models were established to numerically evaluate the effect of the variation in the angulation of superior mesenteric vein (SMV) and splenic vein (SV) on the hemodynamics of portal venous system. RESULTS The angle α (angulation of SMV and SV) in patients with PVT was lower than that in patients without PVT (p < 0.0001), which was the only independent risk factor (odds ratio (OR), 0.90 (95% CI 0.84-0.95); p < 0.0001) for the presence of PVT. With the change in angle α, the flow pattern of blood flow changed greatly, especially the helical flow. When α = 80°, helical flow only appeared at the local PV near the intersection of SMV and SV. When α = 120°, most regions were occupied by the helical flow. In addition, the h2 gradually increased with increasing α, when α = 80°, h2 = 12.6 m/s2; when α = 120°, h2 = 29.3 m/s2. CONCLUSIONS The angulation of SV and SMV was closely associated with PVT development. Helical flow changed following the varying angulation of SV and SMV. Therefore, angulation of SV and SMV may help to identify high-risk cohorts for future PVT development earlier.
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Affiliation(s)
- Yuling Yan
- grid.412901.f0000 0004 1770 1022Department of Gastroenterology and Hepatology, West China Hospital, Sichuan University, 37 Guoxue Lane, Chengdu, 610041 Sichuan People’s Republic of China ,grid.13291.380000 0001 0807 1581Sichuan University-University of Oxford Huaxi Joint for Gastrointestinal Cancer Centre, Chengdu, Sichuan People’s Republic of China
| | - Zhuxiang Xiong
- grid.13291.380000 0001 0807 1581Department of Applied Mechanics, Sichuan University. No, 24 South Section of First Ring Road,, Chengdu, 610065 Sichuan Province People’s Republic of China ,grid.413041.30000 0004 1808 3369Yibin Institute of Industrial Technology/Sichuan University Yibin Park, Yibin, People’s Republic of China
| | - Xiaoze Wang
- grid.412901.f0000 0004 1770 1022Department of Gastroenterology and Hepatology, West China Hospital, Sichuan University, 37 Guoxue Lane, Chengdu, 610041 Sichuan People’s Republic of China ,grid.13291.380000 0001 0807 1581Sichuan University-University of Oxford Huaxi Joint for Gastrointestinal Cancer Centre, Chengdu, Sichuan People’s Republic of China
| | - Li Yang
- grid.412901.f0000 0004 1770 1022Department of Gastroenterology and Hepatology, West China Hospital, Sichuan University, 37 Guoxue Lane, Chengdu, 610041 Sichuan People’s Republic of China ,grid.13291.380000 0001 0807 1581Sichuan University-University of Oxford Huaxi Joint for Gastrointestinal Cancer Centre, Chengdu, Sichuan People’s Republic of China
| | - Tinghui Zheng
- grid.13291.380000 0001 0807 1581Department of Applied Mechanics, Sichuan University. No, 24 South Section of First Ring Road,, Chengdu, 610065 Sichuan Province People’s Republic of China ,grid.413041.30000 0004 1808 3369Yibin Institute of Industrial Technology/Sichuan University Yibin Park, Yibin, People’s Republic of China
| | - Xuefeng Luo
- grid.412901.f0000 0004 1770 1022Department of Gastroenterology and Hepatology, West China Hospital, Sichuan University, 37 Guoxue Lane, Chengdu, 610041 Sichuan People’s Republic of China ,grid.13291.380000 0001 0807 1581Sichuan University-University of Oxford Huaxi Joint for Gastrointestinal Cancer Centre, Chengdu, Sichuan People’s Republic of China
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Wu Y, Wei L, Gao X, Qi Y, Tong Z, Gu Y, Hua Y, Wang L, Wang W, Guo L. Internal valvuloplasty combined with sleeve wrapping in the treatment of severe deep venous incompetence: A case report. Vascular 2021; 30:115-119. [PMID: 33530885 DOI: 10.1177/1708538121990121] [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: 11/15/2022]
Abstract
BACKGROUND The main cause of severe chronic venous insufficiency is deep venous incompetence. Deep venous reconstructive surgeries are reserved for cases that do not show a good response to conservative therapies. METHOD We present the case of a 68-year-old man presenting with swelling, pain, and pigmentation in his left lower limb for 14 years and ulcers for 10 years. Descending venography identified a Kistner's grade IV reflux in the deep vein of the left lower limb. Internal valvuloplasty was performed following Kistner's method. Meanwhile, external wrapping with a 1-cm-wide polyester-urethane vascular patch was performed to strengthen the vein wall in the venospasm condition. RESULTS Symptoms were immediately relieved postoperatively. Refractory ulcers healed five months after the procedure. At the six-month follow-up, color duplex ultrasound of the deep vein of the left lower limb showed no reflux in the proximal segment of the femoral vein. CONCLUSION Internal valvuloplasty combined with sleeve wrapping is feasible in the treatment of severe deep venous incompetence with good short-term results.
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Affiliation(s)
- Yingfeng Wu
- Department of Vascular Surgery, Xuanwu Hospital, Capital Medical University, Beijing, China.,Institute of Vascular Surgery, Capital Medical University, Beijing, China
| | - Libing Wei
- Department of Vascular Surgery, Xuanwu Hospital, Capital Medical University, Beijing, China.,Institute of Vascular Surgery, Capital Medical University, Beijing, China
| | - Xixiang Gao
- Department of Vascular Surgery, Xuanwu Hospital, Capital Medical University, Beijing, China.,Institute of Vascular Surgery, Capital Medical University, Beijing, China
| | - Yixia Qi
- Department of Vascular Surgery, Xuanwu Hospital, Capital Medical University, Beijing, China.,Institute of Vascular Surgery, Capital Medical University, Beijing, China
| | - Zhu Tong
- Department of Vascular Surgery, Xuanwu Hospital, Capital Medical University, Beijing, China.,Institute of Vascular Surgery, Capital Medical University, Beijing, China
| | - Yongquan Gu
- Department of Vascular Surgery, Xuanwu Hospital, Capital Medical University, Beijing, China.,Institute of Vascular Surgery, Capital Medical University, Beijing, China
| | - Yang Hua
- Department of Vascular Ultrasound, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Lili Wang
- Department of Vascular Ultrasound, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Wei Wang
- Surgical Outpatient Department, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Lianrui Guo
- Department of Vascular Surgery, Xuanwu Hospital, Capital Medical University, Beijing, China.,Institute of Vascular Surgery, Capital Medical University, Beijing, China
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Park JH, Choi W, Lee SJ. Adaptive hybrid flow measurement of color Doppler and speckle image velocimetry. ULTRASONICS 2020; 104:106093. [PMID: 32151876 DOI: 10.1016/j.ultras.2020.106093] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 11/14/2019] [Accepted: 12/23/2019] [Indexed: 06/10/2023]
Abstract
Color Doppler (CD) ultrasound has been commonly employed in biomedical field to get hemodynamic information. However, reliable diagnostic evaluation and criteria for vascular diseases may not be provided due to technical limitations of CD, including single-directional measurement, aliasing, and limited imaging conditions. In this study, adaptive hybrid (AH) scheme is proposed to enhance measurement accuracy of conventional CD. It can improve the accuracy of velocity field measurement by replacing erroneous vectors in the measured CD results with the correct vectors obtained from a speckle image velocimetry (SIV) technique. The performance of the proposed AH technique was validated through in vitro experiments for various flow rates and insonation angle conditions, comparing conventional velocimetry techniques. The in vitro experiments demonstrated that the AH technique could measure flow velocity with better accuracy than the CD with bias errors of below 0.7 mm/s. The clinical applicability of the AH was also validated by measuring venous flows at human lower extremity, checking constant volumetric flow rates. Flow rates measured by the AH were maintained along the vein, while the CD and SIV results varied. As a result, the AH can provide improved measurement accuracy without installing a new supplementary equipment. It would be effectively utilized for analyzing flow dynamics and diagnosing valve-related disease.
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Affiliation(s)
- Jun Hong Park
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), 77, Cheongam-ro, Nam-gu, Pohang 37679, Republic of Korea
| | - Woorak Choi
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), 77, Cheongam-ro, Nam-gu, Pohang 37679, Republic of Korea
| | - Sang Joon Lee
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), 77, Cheongam-ro, Nam-gu, Pohang 37679, Republic of Korea.
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Helical flow: A means to identify unstable plaques and a new direction for the design of vascular grafts and stents. Atherosclerosis 2020; 300:34-36. [PMID: 32216972 DOI: 10.1016/j.atherosclerosis.2020.03.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 03/02/2020] [Accepted: 03/05/2020] [Indexed: 12/25/2022]
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7
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Gravity force is not a sole explanation of reflux flow in incompetent great saphenous vein. J Vasc Surg Venous Lymphat Disord 2019; 7:693-698. [PMID: 31281101 DOI: 10.1016/j.jvsv.2019.04.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 04/11/2019] [Indexed: 11/23/2022]
Abstract
OBJECTIVE This study aimed to evaluate the impact of gravity, reservoir size, and competence of the ostial valve on venous reflux in different body positions. METHODS Our study included 61 lower limbs with primary incompetence of the great saphenous vein (GSV). The diameter of the GSV and its cross-sectional area, time-averaged mean velocity (TAMEAN), and reflux time (RT) were measured with duplex ultrasound with pulsed wave Doppler. Reflux volume (RV) and reflux volume flow rate (Q) were calculated. The measurements were carried out in three body positions: horizontal, A; seated upright with stretched legs, B; and vertical, C. Distal automatic cuff compression-decompression (120 mm Hg) was used as a provocation maneuver. RESULTS There was 100% occurrence of reflux in the patient positions B and C. Reflux was observed in 91.8% of cases in position A. All reflux parameters (TAMEAN, RT, Q, RV) and the size of the vein were significantly different in the three studied positions. The patient's height did not influence the magnitude of change in reflux parameters. All reflux parameters increased more significantly when the position changed from A to B than from B to C (TAMEAN, +103% and +37%; GSV diameter, +33% and +5%; RV, +408% and +65%, respectively). CONCLUSIONS Observed positional changes in reflux parameters suggest that gravitational forces are not a sole explanation for reflux flow in incompetent GSV. It is likely that the gravitational effect on venous flow is mediated by the changes in vein diameter and the total volume of the venous reservoir of the leg.
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Parikh V, Kadiwala J, Hidalgo Bastida A, Holt C, Sanami M, Miraftab M, Shakur R, Azzawi M. Small diameter helical vascular scaffolds support endothelial cell survival. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2018; 14:2598-2608. [PMID: 30172863 DOI: 10.1016/j.nano.2018.08.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 07/12/2018] [Accepted: 08/10/2018] [Indexed: 10/28/2022]
Abstract
There is an acute clinical need for small-diameter vascular grafts as a treatment option for cardiovascular disease. Here, we used an intelligent design system to recreate the natural structure and hemodynamics of small arteries. Nano-fibrous tubular scaffolds were fabricated from blends of polyvinyl alcohol and gelatin with inner helices to allow a near physiological spiral flow profile, using the electrospinning technique. Human coronary artery endothelial cells (ECs) were seeded on the inner surface and their viability, distribution, gene expression of mechanosensitive and adhesion molecules compared to that in conventional scaffolds, under static and flow conditions. We show significant improvement in cell distribution in helical vs. conventional scaffolds (94% ± 9% vs. 82% ± 7.2%; P < 0.05) with improved responsiveness to shear stress and better ability to withhold physiological pressures. Our helical vascular scaffold provides an improved niche for EC growth and may be attractive as a potential small diameter vascular graft.
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Affiliation(s)
- Vijay Parikh
- Cardiovascular Research Group, School of Healthcare Science, Manchester Metropolitan University, Manchester, United Kingdom; Institute for Materials Research and Innovation (IMRI), University of Bolton, Manchester, United Kingdom
| | - Juned Kadiwala
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, University of Cambridge, Cambridge, UK
| | - Araida Hidalgo Bastida
- Cardiovascular Research Group, School of Healthcare Science, Manchester Metropolitan University, Manchester, United Kingdom
| | - Cathy Holt
- Institute for Cardiovascular Science, University of Manchester, Manchester, UK
| | - Mohammad Sanami
- Institute for Materials Research and Innovation (IMRI), University of Bolton, Manchester, United Kingdom
| | - Mohsen Miraftab
- Institute for Materials Research and Innovation (IMRI), University of Bolton, Manchester, United Kingdom; Medical Device Consultants Limited, Wilmslow, UK
| | - Rameen Shakur
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, University of Cambridge, Cambridge, UK.
| | - May Azzawi
- Cardiovascular Research Group, School of Healthcare Science, Manchester Metropolitan University, Manchester, United Kingdom.
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Chen HY, Diaz JA, Lurie F, Chambers SD, Kassab GS. Hemodynamics of venous valve pairing and implications on helical flow. J Vasc Surg Venous Lymphat Disord 2018; 6:517-522.e1. [DOI: 10.1016/j.jvsv.2018.02.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 02/01/2018] [Indexed: 10/14/2022]
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Lee SJ, Park JH, Kim JJ, Yeom E. Quantitative Analysis of Helical Flow with Accuracy Using Ultrasound Speckle Image Velocimetry: In Vitro and in Vivo Feasibility Studies. ULTRASOUND IN MEDICINE & BIOLOGY 2018; 44:657-669. [PMID: 29288000 DOI: 10.1016/j.ultrasmedbio.2017.11.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 11/10/2017] [Accepted: 11/20/2017] [Indexed: 06/07/2023]
Abstract
Venous valve dysfunction and induced secondary abnormal flows are closely associated with venous diseases. Thus, detailed analysis of venous valvular flow is invaluable from biological and medical perspectives. However, most of the previous studies on venous perivalvular flows were based on qualitative analysis. On the contrary, quantitative analysis of perivalvular flows has not been fully understood. In this study, we used the ultrasound speckle image velocimetry (SIV) technique, which utilizes the speckle patterns of red blood cells (RBCs) created by ultrasound waves to measure 3-D valvular flows quantitatively. The flow structures obtained with the proposed SIV technique for an in vitro model were compared with those obtained by numerical simulation and the color Doppler method to validate the measurement accuracy of the ultrasound SIV technique. Blood flow in the human great saphenous vein was then measured at various distances from the valve with and without exercise. 3-D valvular flow was analyzed in accordance with the dimensionless index, helical intensity. The results obtained by the proposed method matched well with those obtained by numerical simulation and the color Doppler method. The hemodynamic characteristics of 3-D valvular helical flow which were analyzed experimentally using the SIV method would be used for quantitative diagnosis of venous valvular diseases.
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Affiliation(s)
- Sang Joon Lee
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea.
| | - Jun Hong Park
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea
| | - Jeong Ju Kim
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea
| | - Eunseop Yeom
- School of Mechanical Engineering, Pusan National University, Busan, Republic of Korea
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Neuromuscular electrical stimulation reduces sludge in the popliteal vein. J Vasc Surg Venous Lymphat Disord 2017; 6:154-162. [PMID: 29292116 DOI: 10.1016/j.jvsv.2017.09.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 09/13/2017] [Indexed: 01/24/2023]
Abstract
BACKGROUND The common peroneal nerve stimulator (CPNS) is a UK-approved device for reducing venous thromboembolism (VTE) risk. It resembles a wrist watch and is placed over the common peroneal nerve, discharging electricity at a rate of 1 impulse/s. It has been presumed that as blood flow slows, erythrocytes aggregate into ultrasound-detectable echogenic particles, described as venous sludge. The aim of the study was to determine whether the CPNS reduces venous sludge by using an ultrasound-derived gray-scale (0-255) venous sludge index (VSI). METHODS Twenty-five healthy volunteers had their right popliteal vein video recorded using B-mode ultrasound at 22 frames/s in longitudinal and transverse views, standing and lying. This was performed first with the CPNS off and then with the CPNS on. The CPNS impulse intensity used was set from 1 to 7 for each individual, and the level was sufficient to cause an outward jerking movement of the foot. A single frame of the possible 154 frames, lasting 7 seconds, was selected using a random number generator for the image analysis. The "brightness" of the erythrocyte aggregates (pixels) within a circular sampling area was quantified using the VSI. The brighter the sample, the greater the sludge. RESULTS Values are expressed as median (interquartile range). On standing with the device off, there was a significantly higher VSI (P < .0005) compared with lying (longitudinal view, 27.7 [18.8-41.4] vs 11.7 [5.5-17.5]; transverse view, 20.7 [13.6-32.2] vs 11.4 [6.3-15.9]). Activation of the CPNS significantly reduced all the VSI values (P < .0005) shown (longitudinal view, 2 [1.1-3.2] and 1.5 [0.5-3.1]; transverse view, 1.1 [0.6-2.7] and 0.8 [0.5-2.1]). CONCLUSIONS The CPNS device significantly reduces venous sludge within the popliteal vein irrespective of whether the subject is standing or lying down or of the longitudinal or transverse position of the ultrasound transducer. The principal mode of action of the device in the claim that it may reduce venous thromboembolism risk may be through a reduction of venous sludge. However, the relationship between erythrocyte aggregation, venous stasis, and venous thromboembolism risk requires more investigation.
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Hansen KL, Møller-Sørensen H, Kjaergaard J, Jensen MB, Jensen JA, Nielsen MB. Aortic Valve Stenosis Increases Helical Flow and Flow Complexity: A Study of Intra-Operative Cardiac Vector Flow Imaging. ULTRASOUND IN MEDICINE & BIOLOGY 2017; 43:1607-1617. [PMID: 28495300 DOI: 10.1016/j.ultrasmedbio.2017.03.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 03/21/2017] [Accepted: 03/27/2017] [Indexed: 06/07/2023]
Abstract
Aortic valve stenosis alters blood flow in the ascending aorta. Using intra-operative vector flow imaging on the ascending aorta, secondary helical flow during peak systole and diastole, as well as flow complexity of primary flow during systole, were investigated in patients with normal, stenotic and replaced aortic valves. Peak systolic helical flow, diastolic helical flow and flow complexity during systole differed between the groups (p < 0.0001), and correlated to peak systolic velocity (R = 0.94, 0.87 and 0.88, respectively). The study indicates that aortic valve stenosis increases helical flow and flow complexity, which are measurable with vector flow imaging. For assessment of aortic stenosis and optimization of valve surgery, vector flow imaging may be useful.
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Affiliation(s)
| | | | | | | | - Jørgen Arendt Jensen
- Center for Fast Ultrasound Imaging, DTU Elektro, Technical University of Denmark, Denmark
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Improvement of hemodynamic performance using novel helical flow vena cava filter design. Sci Rep 2017; 7:40724. [PMID: 28112186 PMCID: PMC5256025 DOI: 10.1038/srep40724] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 12/09/2016] [Indexed: 12/25/2022] Open
Abstract
We propose a vena cava filter in which helical flow is created in the filter’s working zone to minimize filter blockage by trapped clots and facilitate the lysis of trapped clots. To validate this new design, we compared five helical flow inducers with different thread pitches in terms of blood flow patterns in the filter. The vena cava was reconstructed based on computed tomography images. Both the numerical simulation and in vitro experiment revealed that the helical flow inducer can effectively create a helical flow in the vessel, thereby subduing the filter structure’s adverse disruption to blood flow, and increasing flow-induced shear stress in the filter center. In addition, the smaller thread pitch helical flow inducer reduced the oscillating shear index and relative residence time on the vessel wall. Moreover, we observed that the helical flow inducer in the vena cava could induce flow rotation both in clockwise and counterclockwise directions. In conclusion, the new design of the filter with the smaller thread pitch inducer is advantageous over the traditional filter in terms of improving local hemodynamics, which may reduce thrombosis build-up after deployment.
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14
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Transforming the best care into the standard for care. J Vasc Surg Venous Lymphat Disord 2016; 4:106-13. [DOI: 10.1016/j.jvsv.2015.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 10/06/2015] [Indexed: 11/16/2022]
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15
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Hemodynamic coupling of a pair of venous valves. J Vasc Surg Venous Lymphat Disord 2014; 2:303-14. [DOI: 10.1016/j.jvsv.2013.09.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Revised: 09/09/2013] [Accepted: 09/22/2013] [Indexed: 11/18/2022]
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