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  1. Article ; Online: Aortic valve neocuspidization and bioprosthetic valves: Evaluating turbulence haemodynamics.

    Manchester, Emily Louise / Pirola, Selene / Pirola, Sergio / Mastroiacovo, Giorgio / Polvani, Gianluca / Pontone, Gianluca / Xu, Xiao Yun

    Computers in biology and medicine

    2024  Volume 171, Page(s) 108123

    Abstract: Aortic valve disease is often treated with bioprosthetic valves. An alternative treatment is aortic valve neocuspidization which is a relatively new reparative procedure whereby the three aortic cusps are replaced with patient pericardium or bovine ... ...

    Abstract Aortic valve disease is often treated with bioprosthetic valves. An alternative treatment is aortic valve neocuspidization which is a relatively new reparative procedure whereby the three aortic cusps are replaced with patient pericardium or bovine tissues. Recent research indicates that aortic blood flow is disturbed, and turbulence effects have yet to be evaluated in either bioprosthetic or aortic valve neocuspidization valve types in patient-specific settings. The aim of this study is to better understand turbulence production in the aorta and evaluate its effects on laminar and turbulent wall shear stress. Four patients with aortic valve disease were treated with either bioprosthetic valves (n=2) or aortic valve neocuspidization valvular repair (n=2). Aortic geometries were segmented from magnetic resonance images (MRI), and 4D flow MRI was used to derive physiological inlet and outlet boundary conditions. Pulsatile large-eddy simulations were performed to capture the full range of laminar, transitional and turbulence characteristics in the aorta. Turbulence was produced in all aortas with highest levels occurring during systolic deceleration. In the ascending aorta, turbulence production is attributed to a combination of valvular skew, valvular eccentricity, and ascending aortic dilation. In the proximal descending thoracic aorta, turbulence production is dependent on the type of arch-descending aorta connection (e.g., a narrowing or sharp bend) which induces flow separation. Laminar and turbulent wall shear stresses are of similar magnitude throughout late systolic deceleration and diastole, although turbulent wall shear stress magnitudes exceed laminar wall shear stresses between 27.3% and 61.1% of the cardiac cycle. This emphasises the significance of including turbulent wall shear stress to improve our comprehension of progressive arterial wall diseases. The findings of this study recommend that aortic valve treatments should prioritise minimising valvular eccentricity and skew in order to mitigate turbulence generation.
    MeSH term(s) Humans ; Animals ; Cattle ; Aortic Valve/diagnostic imaging ; Aortic Valve/surgery ; Blood Flow Velocity/physiology ; Hemodynamics/physiology ; Aorta ; Aortic Valve Disease ; Stress, Mechanical
    Language English
    Publishing date 2024-02-08
    Publishing country United States
    Document type Journal Article
    ZDB-ID 127557-4
    ISSN 1879-0534 ; 0010-4825
    ISSN (online) 1879-0534
    ISSN 0010-4825
    DOI 10.1016/j.compbiomed.2024.108123
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: Modelling Combined Intravenous Thrombolysis and Mechanical Thrombectomy in Acute Ischaemic Stroke: Understanding the Relationship between Stent Retriever Configuration and Clot Lysis Mechanisms.

    Manchester, Emily Louise / Roi, Dylan / Gu, Boram / Xu, Xiao Yun / Lobotesis, Kyriakos

    Life (Basel, Switzerland)

    2021  Volume 11, Issue 11

    Abstract: ... ...

    Abstract Background
    Language English
    Publishing date 2021-11-20
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2662250-6
    ISSN 2075-1729
    ISSN 2075-1729
    DOI 10.3390/life11111271
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article: Evaluation of Computational Methodologies for Accurate Prediction of Wall Shear Stress and Turbulence Parameters in a Patient-Specific Aorta.

    Manchester, Emily Louise / Pirola, Selene / Salmasi, Mohammad Yousuf / O'Regan, Declan P / Athanasiou, Thanos / Xu, Xiao Yun

    Frontiers in bioengineering and biotechnology

    2022  Volume 10, Page(s) 836611

    Abstract: Background: ...

    Abstract Background:
    Language English
    Publishing date 2022-03-24
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2719493-0
    ISSN 2296-4185
    ISSN 2296-4185
    DOI 10.3389/fbioe.2022.836611
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Multiphysics Modelling and Simulation of Thrombolysis via Activated Platelet-Targeted Nanomedicine.

    Gu, Boram / Huang, Yu / Manchester, Emily Louise / Hughes, Alun D / Thom, Simon A McG / Chen, Rongjun / Xu, Xiao Yun

    Pharmaceutical research

    2022  Volume 39, Issue 1, Page(s) 41–56

    Abstract: Purpose: This study establishes a multiphysics simulation platform for both conventional and targeted thrombolysis using tissue plasminogen activator (tPA). Based on our computational results, the effects of therapeutic parameters on the dynamics of ... ...

    Abstract Purpose: This study establishes a multiphysics simulation platform for both conventional and targeted thrombolysis using tissue plasminogen activator (tPA). Based on our computational results, the effects of therapeutic parameters on the dynamics of thrombolysis and the risk of side effects are investigated.
    Methods: The model extends our previously developed one-dimensional(1D) mathematical models for fibrinolysis by incorporating targeted thrombolysis. It consists of two parts: (i) a coupled mathematical model of systemic pharmacokinetics (PK) and pharmacodynamics (PD) and local PD in a 1D occluded artery, and (ii) a mechanistic model for a targeted thrombolytic system via activated platelet-targeted tPA-loaded nanovesicles (tPA-NV), with model parameters derived from our in vitro experiments. A total of 16 therapeutic scenarios are simulated by varying the clot location and composition as well as the dosing regimen with free tPA or tPA-NV.
    Results: Our simulation results indicate that tPA-NV offers several advantages over free tPA for thrombolysis. It reduces systemic exposure of tPA, thereby minimising the risk of bleeding complications. Simulations with different tPA-NV doses reveal that tPA-NV at 10% of the recommended dose can be as effective as the standard regimen with the full recommended dose of free tPA, demonstrating the potential of our tPA-NV as a new thrombolytic strategy with a reduced tPA dose. Moreover, faster recanalisation can be achieved with tPA-NV, especially for platelet-rich(or fibrin-poor) clots.
    Conclusions: Our simulation platform for thrombolysis with well-tuned model parameters can be used to evaluate and optimise treatment regimens of existing and new thrombolytic therapies via benefit/risk assessment under various therapeutic scenarios.
    MeSH term(s) Fibrinolysis ; Fibrinolytic Agents/pharmacology ; Nanomedicine ; Thrombolytic Therapy/methods ; Tissue Plasminogen Activator/pharmacology ; Tissue Plasminogen Activator/therapeutic use
    Chemical Substances Fibrinolytic Agents ; Tissue Plasminogen Activator (EC 3.4.21.68)
    Language English
    Publishing date 2022-01-19
    Publishing country United States
    Document type Journal Article
    ZDB-ID 843063-9
    ISSN 1573-904X ; 0724-8741 ; 0739-0742
    ISSN (online) 1573-904X
    ISSN 0724-8741 ; 0739-0742
    DOI 10.1007/s11095-021-03161-2
    Database MEDical Literature Analysis and Retrieval System OnLINE

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