Loading...
Search for: heart-cycle
0.006 seconds

    Targeted drug delivery of magnetic microbubble for abdominal aortic aneurysm: an in silico study

    , Article Biomechanics and Modeling in Mechanobiology ; Volume 21, Issue 2 , 2022 , Pages 735-753 ; 16177959 (ISSN) Shamloo, A ; Ebrahimi, S ; Ghorbani, G ; Alishiri, M ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2022
    Abstract
    Targeted drug delivery (TDD) to abdominal aortic aneurysm (AAA) using a controlled and efficient approach has recently been a significant challenge. In this study, by using magnetic microbubbles (MMBs) under a magnetic field, we investigated the MMBs performance in TDD to AAA based on the amount of surface density of MMBs (SDMM) adhered to the AAA lumen. The results showed that among the types of MMBs studied in the presence of the magnetic field, micromarkers are the best type of microbubble with a −50 % increase in SDMM adhered to the critical area of AAA. The results show that applying a magnetic field causes the amount of SDMM adhered to the whole area of AAA to increase −1.54 times... 

    Patient-specific fluid–structure interaction simulation of the LAD-ITA bypass graft for moderate and severe stenosis: A doubt on the fractional flow reserve-based decision

    , Article Biocybernetics and Biomedical Engineering ; Volume 42, Issue 1 , 2022 , Pages 143-157 ; 02085216 (ISSN) Tajeddini, F ; Firoozabadi, B ; Pakravan, H. A ; Ahmadi Tafti, S. H ; Sharif University of Technology
    Elsevier B.V  2022
    Abstract
    Fractional flow reserve (FFR)-based decision improves the outcomes of percutaneous coronary intervention (PCI) for some patients, while its effectiveness in improving the results of coronary artery bypass graft (CABG) is unclear, in particular for moderate stenosis. It may be due to the fact that FFR cannot take into account the impacts of competitive flow (CF), intimal hyperplasia (IH), as well as compliance mismatch (CMM). As a result, two questions arise 1) whether FFR is a sufficient factor to decide to perform the CABG for patients with moderate to severe stenosis or not and 2) whether post-operative FFR shows the effectiveness of a graft. To shed light on this matter, two... 

    Spatiotemporal registration and fusion of transthoracic echocardiography and volumetric coronary artery tree

    , Article International Journal of Computer Assisted Radiology and Surgery ; Volume 16, Issue 9 , 2021 , Pages 1493-1505 ; 18616410 (ISSN) Ghodsizad, T ; Behnam, H ; Fatemizadeh, E ; Faghihi Langroudi, T ; Bayat, F ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2021
    Abstract
    Purpose: Cardiac multimodal image fusion can offer an image with various types of information in a single image. Many coronary stenosis, which are anatomically clear, are not functionally significant. The treatment of such kind of stenosis can cause irreversible effects on the patient. Thus, choosing the best treatment planning depend on anatomical and functional information is very beneficial. Methods: An algorithm for the fusion of coronary computed tomography angiography (CCTA) as an anatomical and transthoracic echocardiography (TTE) as a functional modality is presented. CCTA and TTE are temporally registered using manifold learning. A pattern search optimization algorithm, using... 

    Computational investigation of stenosis in curvature of coronary artery within both dynamic and static models

    , Article Computer Methods and Programs in Biomedicine ; Volume 185 , 2020 Biglarian, M ; Momeni Larimi, M ; Hassanzadeh Afrouzi, H ; Moshfegh, A ; Toghraie, D ; Javadzadegan, A ; Rostami, S ; Sharif University of Technology
    Elsevier Ireland Ltd  2020
    Abstract
    Background and Objective: Blood flow variation during cardiac cycle is the main mechanism of atherosclerotic development which is dependent on. Methods: The present work mainly tends to investigate stenosis effect in dynamic curvature of coronary artery. This paper presents numerical investigations on wall shear stress profiles in three-dimensional pulsatile flow through curved stenotic coronary arteries for both static and dynamic model. In order to do so, three-dimensional models related to the curved arteries with two degrees of stenosis (30% and 50%). Results: Lower amount of wall shear stress is found near the inner wall of artery distal to the plaque region (stenosis) and in both... 

    The effect of hematocrit and nanoparticles diameter on hemodynamic parameters and drug delivery in abdominal aortic aneurysm with consideration of blood pulsatile flow

    , Article Computer Methods and Programs in Biomedicine ; Volume 195 , October , 2020 Jafarzadeh, S ; Nasiri Sadr, A ; Kaffash, E ; Goudarzi, S ; Golab, E ; Karimipour, A ; Sharif University of Technology
    Elsevier Ireland Ltd  2020
    Abstract
    Background and Objective: The present article has simulated to investigate the efficient hemodynamic parameters, the drug persistence, and drug distribution on an abdominal aortic aneurysm. Methods: Blood as a non-Newtonian fluid enters the artery acting as a real pulse waveform; its behavior is dependent on hematocrit and strain rate. In this simulation of computational fluid dynamic, magnetic nanoparticles of iron oxide which were in advance coated with the drug, are injected into the artery during a cardiac cycle. A two-phase model was applied to investigate the distribution of these carriers. Results: The results are presented for different hematocrits and the nanoparticle diameter. It... 

    Primary stenosis progression versus secondary stenosis formation in the left coronary bifurcation: a mechanical point of view

    , Article Biocybernetics and Biomedical Engineering ; Volume 39, Issue 1 , 2019 , Pages 188-198 ; 02085216 (ISSN) Jahromi, R ; Pakravan, H. A ; Saidi, M. S ; Firoozabadi, B ; Sharif University of Technology
    Elsevier Sp. z o.o  2019
    Abstract
    Biomechanical forces and hemodynamic factors influence the blood flow and the endothelial cells (ECs) morphology. These factors behave differently beyond the coronary artery stenosis. In the present study, unsteady blood flow in the left coronary artery (LCA) and its atherosclerotic bifurcating vessels, left anterior descending (LAD) and left circumflex (LCX) arteries, were numerically simulated to investigate the risk of plaque length development and secondary plaque formation in the post-stenotic areas. Using fluid–structure interaction (FSI) model, compliance of arterial wall and vessel curvature variations due to cardiac motion were considered. The arteries included plaques at the... 

    Primary stenosis progression versus secondary stenosis formation in the left coronary bifurcation: a mechanical point of view

    , Article Biocybernetics and Biomedical Engineering ; Volume 39, Issue 1 , 2019 , Pages 188-198 ; 02085216 (ISSN) Jahromi, R ; Pakravan, H. A ; Saidi, M. S ; Firoozabadi, B ; Sharif University of Technology
    Elsevier Sp. z o.o  2019
    Abstract
    Biomechanical forces and hemodynamic factors influence the blood flow and the endothelial cells (ECs) morphology. These factors behave differently beyond the coronary artery stenosis. In the present study, unsteady blood flow in the left coronary artery (LCA) and its atherosclerotic bifurcating vessels, left anterior descending (LAD) and left circumflex (LCX) arteries, were numerically simulated to investigate the risk of plaque length development and secondary plaque formation in the post-stenotic areas. Using fluid–structure interaction (FSI) model, compliance of arterial wall and vessel curvature variations due to cardiac motion were considered. The arteries included plaques at the... 

    Margination and adhesion of micro- and nanoparticles in the coronary circulation: A step towards optimised drug carrier design

    , Article Biomechanics and Modeling in Mechanobiology ; Volume 17, Issue 1 , 2018 , Pages 205-221 ; 16177959 (ISSN) Forouzandehmehr, M ; Shamloo, A ; Sharif University of Technology
    Springer Verlag  2018
    Abstract
    Obstruction of left anterior descending artery (LAD) due to the thrombosis or atherosclerotic plaques is the leading cause of death worldwide. Targeted delivery of drugs through micro- and nanoparticles is a very promising approach for developing new strategies in clot-busting or treating restenosis. In this work, we modelled the blood flow characteristics in a patient-specific reconstructed LAD artery by the fluid–solid interaction method and based on physiological boundary conditions. Next, we provided a Lagrangian description of micro- and nanoparticles dynamics in the blood flow considering their Brownian motion and the particle–particle interactions. Our results state that the number of... 

    Pulsatile blood flow in total cavopulmonary connection: a comparison between Y-shaped and T-shaped geometry

    , Article Medical and Biological Engineering and Computing ; Volume 55, Issue 2 , 2017 , Pages 213-224 ; 01400118 (ISSN) Rajabzadeh Oghaz, H ; Firoozabadi, B ; Saidi, M. S ; Monjezi, M ; Navabi Shirazi, M. A ; Malakan Rad, E ; Sharif University of Technology
    Springer Verlag  2017
    Abstract
    Single-ventricle anomaly is a hereditary heart disease that is characterized by anatomical malformations. The main consequence of this malformation is desaturated blood flow, which without proper treatment increases the risk of death. The classical treatment is based on a three-stage palliative procedure which should begin from the first few days of patient’s life. The final stage is known as Fontan procedure, in which inferior vena cava is directly connected to pulmonary arteries without going through the ventricle. This connection is called total cavopulmonary connection (TCPC). After surgery, the single ventricle supplies adequate and saturated systemic blood flow to the body; however,... 

    Life-threatening arrhythmia verification in ICU patients using the joint cardiovascular dynamical model and a bayesian filter

    , Article IEEE Transactions on Biomedical Engineering ; Volume 58, Issue 10 PART 1 , 2011 , Pages 2748-2757 ; 00189294 (ISSN) Sayadi, O ; Shamsollahi, M. B ; Sharif University of Technology
    Abstract
    In this paper, a novel nonlinear joint dynamical model is presented, which is based on a set of coupled ordinary differential equations of motion and a Gaussian mixture model representation of pulsatile cardiovascular (CV) signals. In the proposed framework, the joint interdependences of CV signals are incorporated by assuming a unique angular frequency that controls the limit cycle of the heart rate. Moreover, the time consequence of CV signals is controlled by the same phase parameter that results in the space dimensionality reduction. These joint equations together with linear assignments to observation are further used in the Kalman filter structure for estimation and tracking. Moreover,... 

    Investigation of the effect of high +Gz accelerations on human cardiac function

    , Article Journal of the Mechanical Behavior of Biomedical Materials ; Volume 27 , 2013 , Pages 54-63 ; 17516161 (ISSN) Jamshidi, M ; Ahmadian, M. T ; Sharif University of Technology
    Abstract
    This study investigates the effect of body acceleration on human cardiac function. Finite element analysis is conducted to simulate geometrical and mechanical properties of human heart. Heart geometrical modeling in three-dimension is performed by segmentation of cardiac MRI images. The nonlinear mechanical behavior of myocardium is modeled by Mooney-Rivlin, Polynomial, Ogden and Yeoh hyperelastic material models. Stress-strain curves of myocardial tissue are obtained from experimental compression tests on bovine heart samples. The experimental results are employed for the evaluation of material coefficients by the nonlinear least squares method. Among hyperelastic models, the Yeoh model...