332 results match your criteria Cardiovascular engineering and technology[Journal]


Experimental Assessment of Two Non-Contrast MRI Sequences Used for Computational Fluid Dynamics: Investigation of Consistency Between Techniques.

Cardiovasc Eng Technol 2020 Jul 1. Epub 2020 Jul 1.

Imaging and Technology, University of Dundee, Dundee, UK.

Purpose: Recent studies have noted a degree of variance between the geometries segmented by different groups from 3D medical images that are used in computational fluid dynamics (CFD) simulations of patient-specific cardiovascular systems. The aim of this study was to determine if the applied sequence of magnetic resonance imaging (MRI) also introduced observable variance in CFD results.

Methods: Using a series of phantoms MR images of vessels of known diameter were assessed for the time-of-flight and multi-echo data image combination sequences. Read More

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http://dx.doi.org/10.1007/s13239-020-00473-zDOI Listing

Tissue Ingrowth Markedly Reduces Mechanical Anisotropy and Stiffness in Fibre Direction of Highly Aligned Electrospun Polyurethane Scaffolds.

Cardiovasc Eng Technol 2020 Jul 1. Epub 2020 Jul 1.

Division of Biomedical Engineering, Department of Human Biology, University of Cape Town, Private Bag X3, Observatory, 7935, South Africa.

Purpose: The lack of long-term patency of synthetic vascular grafts currently available on the market has directed research towards improving the performance of small diameter grafts. Improved radial compliance matching and tissue ingrowth into the graft scaffold are amongst the main goals for an ideal vascular graft.

Methods: Biostable polyurethane scaffolds were manufactured by electrospinning and implanted in subcutaneous and circulatory positions in the rat for 7, 14 and 28 days. Read More

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http://dx.doi.org/10.1007/s13239-020-00475-xDOI Listing

Evaluation of the Effect of Crosslinking Method of Poly(Vinyl Alcohol) Hydrogels on Thrombogenicity.

Cardiovasc Eng Technol 2020 Jun 30. Epub 2020 Jun 30.

Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR, USA.

Purpose: Crosslinked poly(vinyl alcohol) (PVA) is a biomaterial that can be used for multiple cardiovascular applications. The success of implanted biomaterials is contingent on the properties of the material. A crucial consideration for blood-contacting devices is their potential to incite thrombus formation, which is dependent on the material surface properties. Read More

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http://dx.doi.org/10.1007/s13239-020-00474-yDOI Listing

Mitral Valve Posterior Leaflet Reconstruction Using Extracellular Matrix: In Vitro Evaluation.

Cardiovasc Eng Technol 2020 Jun 26. Epub 2020 Jun 26.

Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus, Denmark.

Purpose: To investigate the anatomical and functional effects of complete surgical reconstruction of the posterior mitral leaflet and associated chordae tendineae with a patch made of 2-ply small intestinal submucosal extracellular matrix in vitro.

Methods: Seven explanted mitral valves with intact subvalvular apparatus from 80-kg pigs were evaluated in a left heart simulator and served as their own controls. After testing the native valve, the mitral posterior leaflet and associated chordae tendineae were excised and reconstructed by using the 2-ply small intestinal submucosa extracellular matrix patch. Read More

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http://dx.doi.org/10.1007/s13239-020-00472-0DOI Listing

Influence of the Adopted Balloon Modeling Strategies in the Stent Deployment Procedure: An In-Silico Analysis.

Cardiovasc Eng Technol 2020 Jun 15. Epub 2020 Jun 15.

CMEMS - UMinho, Guimarães, Portugal.

Purpose: As the promoter of the stent expansion, the balloon plays a very important role, offering a strong influence on the deployment process. Balloon-artery interaction is pointed as a probable cause of restenosis, stressing the relevance of balloon modeling when simulating the stenting procedure. In this work, an in-silico study of the balloon modeling strategies is performed. Read More

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http://dx.doi.org/10.1007/s13239-020-00470-2DOI Listing

Residual Stress Estimates from Multi-cut Opening Angles of the Left Ventricle.

Cardiovasc Eng Technol 2020 Jun 15. Epub 2020 Jun 15.

School of Mathematics and Statistics, University of Glasgow, Glasgow, G12 8SQ, UK.

Purpose: Residual stress tensor has an essential influence on the mechanical behaviour of soft tissues and can be particularly useful in evaluating growth and remodelling of the heart and arteries. It is currently unclear if one single radial cut using the opening angle method can accurately estimate the residual stress. In many previous models, it has been assumed that a single radial cut can release the residual stress in a ring of the artery or left ventricle. Read More

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http://dx.doi.org/10.1007/s13239-020-00467-xDOI Listing

Haemodynamic Effect of Left Atrial and Left Ventricular Cannulation with a Rapid Speed Modulated Rotary Blood Pump During Rest and Exercise: Investigation in a Numerical Cardiorespiratory Model.

Cardiovasc Eng Technol 2020 Jun 16. Epub 2020 Jun 16.

Innovative Cardiovascular Engineering and Technology Laboratory, Critical Care Research Group, The Prince Charles Hospital, Brisbane, Queensland, Australia.

Purpose: The left atrium and left ventricle are the primary inflow cannulation sites for heart failure patients supported by rotary blood pumps (RBPs). Haemodynamic differences exist between inflow cannulation sites and have been well characterized at rest, yet the effect during exercise with the same centrifugal RBP has not been previously well established. The purpose of this study was to investigate the hemodynamic effect of inflow cannulation site during rest and exercise with the same centrifugal RBP. Read More

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http://dx.doi.org/10.1007/s13239-020-00471-1DOI Listing

Biomechanical Assessment of Bicuspid Aortic Valve Phenotypes: A Fluid-Structure Interaction Modelling Approach.

Cardiovasc Eng Technol 2020 Jun 9. Epub 2020 Jun 9.

Department of Mechanical Engineering, University of Birmingham, Birmingham, B15 2TT, UK.

Purpose: Bicuspid aortic valve (BAV) is a congenital heart malformation with phenotypic heterogeneity. There is no prior computational study that assesses the haemodynamic and valve mechanics associated with BAV type 2 against a healthy tricuspid aortic valve (TAV) and other BAV categories.

Methods: A proof-of-concept study incorporating three-dimensional fluid-structure interaction (FSI) models with idealised geometries (one TAV and six BAVs, namely type 0 with lateral and anterior-posterior orientations, type 1 with R-L, N-R and N-L leaflet fusion and type 2) has been developed. Read More

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http://dx.doi.org/10.1007/s13239-020-00469-9DOI Listing

Role of Occlusion Position in Coronary Artery Fistulas with Terminal Aneurysms: A Hemodynamic Perspective.

Cardiovasc Eng Technol 2020 Jun 1. Epub 2020 Jun 1.

Department of Applied Mechanics, Sichuan University, No. 24, South Section of First Ring Road, Chengdu, 610065, Sichuan, People's Republic of China.

Purpose: Thrombosis within an occluded coronary arterial fistula (CAF) may cause angina and myocardial infarction. This study aims to estimate how the occlusion position of CAFs with terminal aneurysm affects the risk stratification of thrombosis in the fistula in terms of hemodynamics.

Methods: Twelve CAF models were reconstructed based on patient-specific computed tomography angiogram (CTA) images. Read More

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http://dx.doi.org/10.1007/s13239-020-00468-wDOI Listing

An Insight to the Role of Thermal Effects on the Onset of Atrioesophageal Fistula: A Computer Model of Open-Irrigated Radiofrequency Ablation.

Cardiovasc Eng Technol 2020 May 14. Epub 2020 May 14.

Department of Mechanical and Materials Engineering, University of Western Ontario, London, N6A 5B8, Canada.

Purpose: Atrial fibrillation (AF) is the most common heart rhythm disorder in the world. Radiofrequency catheter ablation (RFCA) has become the preferred method of treatment for drug-refractory AF. One of the rare (< 0. Read More

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http://dx.doi.org/10.1007/s13239-020-00465-zDOI Listing

Effect of the Center Post Establishment and Its Design Variations on the Performance of a Centrifugal Rotary Blood Pump.

Cardiovasc Eng Technol 2020 May 14. Epub 2020 May 14.

ShenZhen Core Medical Technology CO, LTD, Shenzhen, 518055, China.

Purpose: The main purpose is to compare the characteristics and performance of a centrifugal blood pump with and without center post. Furthermore, to propose a center post design guide for the development of centrifugal blood pumps: finding the appropriate height and diameter of the center post.

Methods: A centrifugal blood pump with different center post configurations is investigated using Computational Fluid Dynamics (CFD) in an extensive parametric approach. Read More

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http://dx.doi.org/10.1007/s13239-020-00464-0DOI Listing

Long-Term Venovenous Connection for Extracorporeal Carbon Dioxide Removal (ECCOR)-Numerical Investigation of the Connection to the Common Iliac Veins.

Cardiovasc Eng Technol 2020 May 13. Epub 2020 May 13.

Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Medical Faculty, RWTH Aachen University, Aachen, Germany.

Purpose: Currently used cannulae for extracorporeal carbon dioxide removal (ECCOR) are associated with complications such as thrombosis and distal limb ischemia, especially for long-term use. We hypothesize that the risk of these complications is reducible by attaching hemodynamically optimized grafts to the patient's vessels. In this study, as a first step towards a long-term stable ECCOR connection, we investigated the feasibility of a venovenous connection to the common iliac veins. Read More

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http://dx.doi.org/10.1007/s13239-020-00466-yDOI Listing

The Ryanodine Receptor Contributes to the Lysophosphatidylcholine-Induced Mineralization in Valvular Interstitial Cells.

Cardiovasc Eng Technol 2020 Jun 30;11(3):316-327. Epub 2020 Apr 30.

Department of Bioengineering, Rice University, 6100 Main St., MS 142, Houston, TX, 77005, USA.

Purpose: Fibrocalcific aortic valve disease (CAVD) is caused by the deposition of calcific nodules in the aortic valve leaflets, resulting in progressive loss of function that ultimately requires surgical intervention. This process is actively mediated by the resident valvular interstitial cells (VICs), which, in response to oxidized lipids, transition from a quiescent to an osteoblast-like state. The purpose of this study was to examine if the ryanodine receptor, an intracellular calcium channel, could be therapeutically targeted to prevent this phenotypic conversion. Read More

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http://dx.doi.org/10.1007/s13239-020-00463-1DOI Listing

Non-Invasive Quantification of Ventricular Contractility, Arterial Elastic Function and Ventriculo-Arterial Coupling from a Single Diagnostic Encounter Using Simultaneous Arterial Tonometry and Magnetic Resonance Imaging.

Cardiovasc Eng Technol 2020 Jun 20;11(3):283-294. Epub 2020 Apr 20.

Department of Cardiology, St. Vincent's Hospital, 390 Victoria Street, Darlinghurst, Sydney, NSW, 2010, Australia.

Purpose: Optimal assessment of cardiovascular performance requires simultaneous measurement of load independent left ventricular (LV) contractility, arterial function and LV/arterial coupling. We aimed to demonstrate feasibility of non-invasive ventricular pressure-volume and aortic pressure-flow-impedance measurements using simultaneous arterial tonometry (AT) and cardiovascular magnetic resonance imaging (CMRI).

Methods: 21 consecutive patients referred for CMRI were enrolled to undergo a simultaneous AT and CMRI protocol. Read More

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http://dx.doi.org/10.1007/s13239-020-00462-2DOI Listing

Large-Eddy Simulations of Flow in the FDA Benchmark Nozzle Geometry to Predict Hemolysis.

Cardiovasc Eng Technol 2020 Jun 15;11(3):254-267. Epub 2020 Apr 15.

Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, USA.

Purpose: Modeling of hemolysis due to fluid stresses faces significant methodological challenges, particularly in geometries with turbulence or complex flow patterns. It is currently unclear how existing phenomenological blood-damage models based on laminar viscous stresses can be implemented into turbulent computational fluid dynamics simulations. The aim of this work is to generalize the existing laminar models to turbulent flows based on first principles, and validate this generalization with existing experimental data. Read More

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http://dx.doi.org/10.1007/s13239-020-00461-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7230024PMC

Transcatheter Mitral Valve Replacement: State of the Art.

Cardiovasc Eng Technol 2020 Jun 4;11(3):229-253. Epub 2020 Mar 4.

The Heart Valve Performance Laboratory, School of Engineering, Faculty of Applied Science, University of British Columbia Okanagan, Kelowna, BC, V1V 1V7, Canada.

The emergence of transcatheter aortic valve replacement (TAVR) has segued the development of transcatheter mitral valve (MV) repair devices. Transcatheter mitral valve repair has become a well-established alternative for patients with severe primary and secondary mitral regurgitation (MR) and with a perceived surgical risk. Transcatheter mitral valve replacement (TMVR) could become a more complete form of reduction of severe MR compared to MV repair devices, albeit with significant engineering challenges and all the risks associated with a bioprosthetic heart valve. Read More

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http://dx.doi.org/10.1007/s13239-020-00460-4DOI Listing

Hemodynamic Effects of Additional Pulmonary Blood Flow on Glenn and Fontan Circulation.

Cardiovasc Eng Technol 2020 Jun 18;11(3):268-282. Epub 2020 Feb 18.

Guangdong Provincial Key Laboratory of South China Structural Heart Disease, Department of Cardiovascular Surgery, Guangdong Provincial People's Hospital, Guangdong Cardiovascular Institute, Guangdong Academy of Medical Sciences, Guangzhou, 510000, China.

Purpose: Additional pulmonary blood flow (APBF) can provide better pulsating blood flow and systemic arterial oxygen saturation, while low blood pulsation and low oxygen saturation are defects of the Fontan and Glenn procedure. Studying the hemodynamic effect of APBF is beneficial for clinical decisions. This study aimed to explore the effect on particle washout, as well as the differences among the sensitivities of both different hemodynamic parameters and different procedures to APBF. Read More

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http://dx.doi.org/10.1007/s13239-020-00459-xDOI Listing

Respiration and Heat Shock Protein After Short-Term Heating/Stretch-Fixing on Smooth Muscle Cells.

Cardiovasc Eng Technol 2020 Jun 3;11(3):308-315. Epub 2020 Feb 3.

Department of Applied Physics and Physico-Informatics, Faculty of Science and Technology, Keio University, Yokohama, Kanagawa, 223-8522, Japan.

Purpose: A treatment device without a stent is needed for peripheral stenotic artery treatment. We have proposed short-term heating balloon angioplasty, photo-thermo dynamic balloon angioplasty (PTDBA). Though smooth muscle cells (SMCs) after PTDBA are fixed in a stretched formation in a porcine model, influences of this stimulus on SMCs have not been investigated. Read More

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http://dx.doi.org/10.1007/s13239-020-00458-yDOI Listing

Post-exercise Response of Arterial Parameters for Arterial Health Assessment Using a Microfluidic Tactile Sensor and Vibration-Model-Based Analysis: A Proof-of-Concept Study.

Cardiovasc Eng Technol 2020 Jun 30;11(3):295-307. Epub 2020 Jan 30.

Department of Human Movement Sciences, Old Dominion University, Norfolk, VA, USA.

Objective: Arterial stiffness and endothelial function are two established surrogate markers of subclinical atherosclerosis and are quantified by three arterial parameters: elasticity, viscosity and radius of the arterial wall. Yet, the current methods for their assessment are unsuitable for routine use. Post-exercise response of the cardiovascular (CV) system serves as a more sensitive detection of subclinical arterial abnormalities that are not apparent at-rest. Read More

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http://dx.doi.org/10.1007/s13239-020-00454-2DOI Listing

A Metabolic Intravascular Platform to Study FDG Uptake in Vascular Injury.

Cardiovasc Eng Technol 2020 Jun 30;11(3):328-336. Epub 2020 Jan 30.

Department of Cardiovascular Medicine, Mayo Clinic School of Medicine Rochester, Mayo Clinic, 200 First St SW, Rochester, MN, 55902, USA.

Purpose: Metabolic alterations underlie many pathophysiological conditions, and their understanding is critical for the development of novel therapies. Although the assessment of metabolic changes in vivo has been historically challenging, recent developments in molecular imaging have allowed us to study novel metabolic research concepts directly in the living subject, bringing us closer to patients. However, in many instances, there is need for sensors that are in close proximity to the organ under investigation, for example to study vascular metabolism. Read More

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http://dx.doi.org/10.1007/s13239-020-00457-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7230012PMC

Speckle-Tracking Echocardiography Enables Model-Based Identification of Regional Stiffness Indices in the Left Ventricular Myocardium.

Cardiovasc Eng Technol 2020 Apr 29;11(2):176-187. Epub 2020 Jan 29.

College of Engineering and Computing, University of South Carolina, Columbia, SC, USA.

Introduction: Left ventricular (LV) remodeling is a critical process underlying heart failure (HF) development and progression. While LV global longitudinal strain determined by speckle-tracking echocardiography (STE) provides a promising basis to monitor LV remodeling, reported strain measures are limited by the masking of regional differences and a dependency on hemodynamic load.

Objectives: Our goal is to extend two-dimensional STE to enhance regional mechanical assessment of the LV myocardium-providing clinically accessible and load-independent response variables that directly reflect the LV remodeling process. Read More

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http://dx.doi.org/10.1007/s13239-020-00456-0DOI Listing

Correlation Between Doppler Derived Carotid Artery Corrected Flow Time and Pressure Transducer Derived Radial Artery Corrected Flow Time: A Prospective Observational Study.

Cardiovasc Eng Technol 2020 Apr 16;11(2):128-133. Epub 2020 Jan 16.

Department of Anaesthesiology, Pain Medicine & Critical Care, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India.

Purpose: Carotid artery corrected flow time (cFT) derived from Doppler USG is a known predictor of volume responsiveness. However, it can't be obtained continuously, and is operator dependent. In this prospective study, correlation between Doppler derived carotid artery cFT and pressure transducer derived radial artery cFT was evaluated in adult patients undergoing surgery under general anaesthesia. Read More

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http://dx.doi.org/10.1007/s13239-020-00455-1DOI Listing

Inhibition of miR-217 Protects Against Myocardial Ischemia-Reperfusion Injury Through Inactivating NF-κB and MAPK Pathways.

Cardiovasc Eng Technol 2020 Apr 8;11(2):219-227. Epub 2020 Jan 8.

Department of Cardiovascular Medicine, Heji Hospital Affiliated to Changzhi Medical College, 271 East Taihang Street, Changzhi, 046000, Shanxi, China.

Purpose: Recent studies have demonstrated that miRNAs play a vital role in regulating myocardial ischemia/reperfusion injury (MIRI). MiR-217 has been proven to be implicated in cardiac diseases such as chronic heart failure and cardiac myxoma. However, the role of miR-217 in MIRI is not clear. Read More

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http://dx.doi.org/10.1007/s13239-019-00452-zDOI Listing

A Highly Conductive 3D Cardiac Patch Fabricated Using Cardiac Myocytes Reprogrammed from Human Adipogenic Mesenchymal Stem Cells.

Cardiovasc Eng Technol 2020 Apr 8;11(2):205-218. Epub 2020 Jan 8.

Stem Cell Engineering, Texas Heart Institute, 6770 Bertner Avenue, Houston, TX, 77225-0345, USA.

Purpose: The objective of this study was to bioengineer 3D patches from cardiac myocytes that have been reprogrammed from human adipogenic mesenchymal stem cells (hADMSCs).

Methods: Human adipogenic mesenchymal stem cells (hADMSCs) were reprogrammed to form cardiac myocytes using transcription factors ETS2 and MESP1. Reprogrammed cardiac myocytes were cultured in a fibrin gel to bioengineer 3D patch patches. Read More

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http://dx.doi.org/10.1007/s13239-019-00451-0DOI Listing

Effect of Aortic Wall Deformation with Healthy and Calcified Annulus on Hemodynamic Performance of Implanted On-X Valve.

Cardiovasc Eng Technol 2020 Apr 7;11(2):141-161. Epub 2020 Jan 7.

School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran.

Introduction: In this research, the hemodynamic performance of a 23-mm On-X bileaflet mechanical heart valve (BMHV) was investigated with the realistic geometry model of the valve and the deformable aorta in accelerating systole. In addition, the effect of ascending aorta flexibility and aortic annulus calcification on the complex blood flow characteristics were investigated.

Methods: The geometry of the aorta is derived from the medical images, and the Ogden model has been utilized for the mechanical behavior of the ascending aorta. Read More

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http://dx.doi.org/10.1007/s13239-019-00453-yDOI Listing

Influence of Configuration on Stress Distribution of Pulmonary Monocusp Leaflet.

Cardiovasc Eng Technol 2020 Apr 18;11(2):134-140. Epub 2019 Dec 18.

Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, 100083, China.

Purpose: For the relief of right ventricular outflow tract obstruction in operative treatment of tetralogy of Fallot and other complex congenital heart diseases, transannular monocusp patch operations are often necessary to prevent right ventricular pressure overload and reduce pulmonary regurgitation. However, long-term durability of a monocusp leaflet is unsatisfactory, its failure is believed to be related to mechanical stress, whose distribution is primarily affected by geometric configurations. Therefore, the influence of several geometrical parameters on stress distribution of leaflet is investigated. Read More

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http://dx.doi.org/10.1007/s13239-019-00449-8DOI Listing

Numerical Simulation of Magnetic Drug Targeting to the Stenosis Vessel Using FeO Magnetic Nanoparticles Under the Effect of Magnetic Field of Wire.

Cardiovasc Eng Technol 2020 Apr 18;11(2):162-175. Epub 2019 Dec 18.

Department of Mechanical Engineering, Urmia University of Technology (UUT), P.O. Box: 57166-419, Urmia, Iran.

Purpose: In the present paper, the magnetic drug targeting using drug coated FeO nanoparticles to the stenosis region of the vessel was investigated. The problem was solved for various magnetic numbers. Moreover, the effect of the location of the wire, as a magnetic source, on the MDT was studied. Read More

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http://dx.doi.org/10.1007/s13239-019-00446-xDOI Listing

Future Balloon-Expandable Stents: High or Low-Strength Materials?

Cardiovasc Eng Technol 2020 Apr 13;11(2):188-204. Epub 2019 Dec 13.

Department of Cardiology, Massih-Daneshvari Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Purpose: Recent progress in material science allows researchers to use novel materials with enhanced capabilities like optimum biodegradability, higher strength, and flexibility in the design of coronary stents. Considering the wide range of mechanical properties of existing and newfangled materials, finding the influence of variations in mechanical properties of stent materials is critical for developing a practical design.

Methods: The sensitivity of stent functional characteristics to variations in its material plastic properties is obtained through FEM modeling. Read More

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http://dx.doi.org/10.1007/s13239-019-00450-1DOI Listing

A Systematic Review for the Design of In Vitro Flow Studies of the Carotid Artery Bifurcation.

Cardiovasc Eng Technol 2020 Apr 10;11(2):111-127. Epub 2019 Dec 10.

University of Twente, 7500 AE, Enschede, The Netherlands.

Purpose: In vitro blood flow studies in carotid artery bifurcation models may contribute to understanding the influence of hemodynamics on carotid artery disease. However, the design of in vitro blood flow studies involves many steps and selection of imaging techniques, model materials, model design, and flow visualization parameters. Therefore, an overview of the possibilities and guidance for the design process is beneficial for researchers with less experience in flow studies. Read More

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http://dx.doi.org/10.1007/s13239-019-00448-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7082306PMC

Hemodynamic Effects of Multiple Overlapping Uncovered Stents on Aortic Dissection: Surgical Strategies and Implications for False Lumen Thrombosis.

Cardiovasc Eng Technol 2020 Feb 9;11(1):24-35. Epub 2019 Dec 9.

Department of Mechanics, Tianjin University, 92 Weijin Road, Tianjin, 300072, China.

Purpose: Multiple overlapping uncovered stents (MOUS) are employed to promote false lumen thrombosis in the aortic dissections (AD), when the tears are in close vicinity to the branch vessels. However, the overall rate of false lumen thrombosis remains unsatisfactory. This study was performed to investigate the hemodynamic influence of MOUS on aortic dissection to shed some light on the mechanism of post-stenting false lumen thrombosis. Read More

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http://dx.doi.org/10.1007/s13239-019-00443-0DOI Listing
February 2020

Evaluation of a Desktop 3D Printed Rigid Refractive-Indexed-Matched Flow Phantom for PIV Measurements on Cerebral Aneurysms.

Cardiovasc Eng Technol 2020 Feb 9;11(1):14-23. Epub 2019 Dec 9.

Department of Mechanical and Industrial Engineering, University of South Africa, Johannesburg, South Africa.

Purpose: Fabrication of a suitable flow model or phantom is critical to the study of biomedical fluid dynamics using optical flow visualization and measurement methods. The main difficulties arise from the optical properties of the model material, accuracy of the geometry and ease of fabrication.

Methods: Conventionally an investment casting method has been used, but recently advancements in additive manufacturing techniques such as 3D printing have allowed the flow model to be printed directly with minimal post-processing steps. Read More

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http://dx.doi.org/10.1007/s13239-019-00444-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7002330PMC
February 2020

The Implementation of an Adjustable Afterload Module for Ex Situ Heart Perfusion.

Cardiovasc Eng Technol 2020 Feb 3;11(1):96-110. Epub 2019 Dec 3.

Division of Cardiovascular Surgery, Toronto General Hospital, University Health Network, Toronto, ON, Canada.

Purpose: Windkessel impedance analysis has proven to be an effective technique for instituting artificial afterload on ex situ hearts. Traditional fixed parameter afterload modules, however, are unable to handle the changing contractile conditions associated with prolonged ex situ heart perfusion. In this paper, an adjustable afterload module is described comprising of three fully adjustable sub-components: a systemic resistor, a proximal resistor and a compliance chamber. Read More

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http://dx.doi.org/10.1007/s13239-019-00447-wDOI Listing
February 2020

Hydrodynamic Resistance of Intracranial Flow-Diverter Stents: Measurement Description and Data Evaluation.

Cardiovasc Eng Technol 2020 Feb 3;11(1):1-13. Epub 2019 Dec 3.

Department of Hydrodynamic Systems, Faculty of Mechanical Engineering, Budapest University of Technology and Economics, Budapest, Hungary.

Purpose: Intracranial aneurysms are malformations forming bulges on the walls of brain arteries. A flow diverter device is a fine braided wire structure used for the endovascular treatment of brain aneurysms. This work presents a rig and a protocol for the measurement of the hydrodynamic resistance of flow diverter stents. Read More

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http://dx.doi.org/10.1007/s13239-019-00445-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7002337PMC
February 2020

Cardiac Output Monitoring in Children, Adolescents and Adults Based on Pulse Contour Analysis: Comparison with Echocardiography-Derived Data and Identification of Factors Associated with Their Differences.

Cardiovasc Eng Technol 2020 Feb 27;11(1):67-83. Epub 2019 Nov 27.

Departamento de Fisiología, Facultad de Medicina, Centro Universitario de Investigación, Innovación y Diagnóstico Arterial (CUiiDARTE), Universidad de la República, General Flores 2125, 11800, Montevideo, Uruguay.

Purpose: Through pulse contour analysis (PCA) devices would enable to obtain non-invasive operator-independent cardiac output (CO) measurements [CO(PCA)]. The agreement between CO(PCA) and data from two-dimensional [CO(2D)] or Doppler [CO(VTI)] echocardiography (references) remains controversial.

Aims: To analyze: (1) CO(PCA), CO(2D) and CO(VTI) agreement, (2) determinants of methods' differences in measured CO values. Read More

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http://dx.doi.org/10.1007/s13239-019-00439-wDOI Listing
February 2020

Balloon Aortic Valvuloplasty Using a Non-Occlusive Balloon Catheter: First Animal Experience.

Cardiovasc Eng Technol 2020 Feb 18;11(1):59-66. Epub 2019 Nov 18.

Division of Cardiology, University of Stellenbosch and Tygerberg Academic Hospital, Cape Town, South Africa.

Background: Transcatheter aortic valve implants (TAVI) have revolutionised the treatment of elderly patients requiring aortic valve replacement. These patients often do not tolerate balloon valvuloplasty well, and a valvuloplasty balloon that would allow a degree of continued cardiac output during expansion would be beneficial. We tested such a balloon and describe our results in the sheep model. Read More

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http://dx.doi.org/10.1007/s13239-019-00442-1DOI Listing
February 2020

Effects of Normal Variation in the Rotational Position of the Aortic Root on Hemodynamics and Tissue Biomechanics of the Thoracic Aorta.

Cardiovasc Eng Technol 2020 Feb 7;11(1):47-58. Epub 2019 Nov 7.

Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA.

Purpose: Variation in the rotational position of the aortic root relative to the left ventricle is present in normal trileaflet aortic valves. Its impact on the resulting fluid mechanics of blood flow in the thoracic aorta and structural mechanics in the aortic wall are unknown. We aimed to determine the regional hemodynamic and biomechanical differences in different rotational positions of the normal aortic root (clockwise, central, and counterclockwise positions). Read More

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http://dx.doi.org/10.1007/s13239-019-00441-2DOI Listing
February 2020

A New Approach Based on a Multiobjective Evolutionary Algorithm for Accurate Control of Flow Rate and Blood Pressure in Cardiac Bioreactors.

Cardiovasc Eng Technol 2020 Feb 30;11(1):84-95. Epub 2019 Oct 30.

Département de Génie Mécanique, Université Laval, Québec, QC, G1V 0A6, Canada.

Purpose: Accurately reproducing physiological and time-varying variables in cardiac bioreactors is a difficult task for conventional control methods. This paper presents a new controller based on a genetic algorithm for the control of a cardiac bioreactor dedicated to the study and conditioning of heart valve substitutes.

Methods: A multi-objective genetic algorithm was designed to obtain an accurate simultaneous reproduction of physiological periodic time functions of the three most relevant variables characterizing the blood flow in the aortic valve. Read More

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http://dx.doi.org/10.1007/s13239-019-00440-3DOI Listing
February 2020

Experimental and Numerical Simulation of Biodegradable Stents with Different Strut Geometries.

Cardiovasc Eng Technol 2020 Feb 29;11(1):36-46. Epub 2019 Oct 29.

Department of Applied Mechanics, Sichuan University, Chengdu, 610065, China.

Objective: Biodegradable stents represent a new technological development in the field of cardiovascular angioplasty. The stent geometry plays a crucial role in determining stent performance.

Methods: This study describes four stent models with various strut geometries (circular, triangular, hexagonal, and spline) and identical links. Read More

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http://dx.doi.org/10.1007/s13239-019-00433-2DOI Listing
February 2020
1 Read

Non-physiologic Bioreactor Processing Conditions for Heart Valve Tissue Engineering.

Cardiovasc Eng Technol 2019 12 24;10(4):628-637. Epub 2019 Oct 24.

Cardiac Regenerative Surgery Research Laboratories of The Ward Family Heart Center, Children's Mercy Kansas City, 2401 Gillham Road, Kansas City, MO, 64108, USA.

Purpose: Conventional methods of seeding decellularized heart valves for heart valve tissue engineering have led to inconsistent results in interstitial cellular repopulation, particularly of the distal valve leaflet, and notably distinct from documented re-endothelialization. The use of bioreactor conditioning mimicking physiologic parameters has been well explored but cellular infiltration remains challenging. Non-characteristic, non-physiologic conditioning parameters within a bioreactor, such as hypoxia and cyclic chamber pressure, may be used to increase the cellular infiltration leading to increased recellularization. Read More

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http://dx.doi.org/10.1007/s13239-019-00438-xDOI Listing
December 2019
1 Read

Cardiothoracic Morphology Measures in Heart Failure Patients to Inform Device Designs.

Cardiovasc Eng Technol 2019 12 21;10(4):543-552. Epub 2019 Oct 21.

Virginia Tech-Wake Forest University School of Biomedical Engineering and Sciences, 575 N. Patterson Ave., Suite 120, Winston-Salem, NC, 27101, USA.

Purpose: Approximately 5.7 million people in the US are affected by congestive heart failure. This study aimed to quantitatively evaluate cardiothoracic morphology and variability within a cohort of heart failure patients for the purpose of optimally engineering cardiac devices for a variety of heart failure patients. Read More

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http://dx.doi.org/10.1007/s13239-019-00436-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6868344PMC
December 2019
1 Read

Cilostazol Promotes Angiogenesis and Increases Cell Proliferation After Myocardial Ischemia-Reperfusion Injury Through a cAMP-Dependent Mechanism.

Cardiovasc Eng Technol 2019 12 17;10(4):638-647. Epub 2019 Oct 17.

Department of Cardiology, The Affiliated Huaian No.1 People's Hospital of Nanjing Medical University, Huai'an, 223300, Jiangsu, China.

Purpose: Previous study indicated the protective role of cilostazol in ischemia-reperfusion (I/R) injury. Here, we aimed to explore the function of cilostazol in myocardial I/R injury and the underlying mechanism.

Methods: The myocardial I/R injury rat model was constructed, and the expression levels of vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), basic fibroblast growth factor (bFGF), platelet-derived growth factor receptor b (PDGF-B) and the number of new blood vessels were measured by qRT-PCR and immunohistochemistry. Read More

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http://dx.doi.org/10.1007/s13239-019-00435-0DOI Listing
December 2019
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Three-Dimensional Contractile Mechanics of Artery Accounting for Curl of Axial Strip Sectioned from Vessel Wall.

Cardiovasc Eng Technol 2019 12 17;10(4):604-617. Epub 2019 Oct 17.

, Tokyo, Japan.

Purpose: It is well known that a sliced ring of arterial wall opens by a radial cut. An axial strip sectioned from arterial wall also curls into an arc. These phenomena imply that there exist residual strains in the circumferential and axial directions. Read More

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http://dx.doi.org/10.1007/s13239-019-00434-1DOI Listing
December 2019

Haemodynamics Study of Tapered Stents Intervention to Tapered Arteries.

Cardiovasc Eng Technol 2019 12 15;10(4):583-589. Epub 2019 Oct 15.

School of Mechanical Engineering, Jiangsu University, Zhenjiang, 212013, Jiangsu, China.

Purpose: In-stent restenosis (ISR) is related to local haemodynamics in the arteries after stent intervention. However, the haemodynamics of stents implanted into tapered vessels is rarely studied and remains unclear. This study aimed to study the haemodynamic performance of a stent in a tapered artery to reveal the haemodynamic differences between tapered and cylindrical stents after stent implantation and guide the stent selection for the treatment of coronary artery stenosis. Read More

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http://dx.doi.org/10.1007/s13239-019-00437-yDOI Listing
December 2019
2 Reads

Vascular Parameters for Ambulatory Monitoring of Congestive Heart Failure Patients: Proof of Concept.

Cardiovasc Eng Technol 2019 12 9;10(4):618-627. Epub 2019 Oct 9.

Instituto Superior de Investigaciones Biológicas, Consejo Nacional de Investigaciones Científicas y Técnicas, Chacabuco 461, Tucumán, Argentina.

Purpose: Prompt detection of congestion is an essential target in order to prevent heart failure (HF) related hospitalization, being ambulatory monitoring a promising strategy to do so. A successful non-invasive ambulatory monitoring system requires automatic devices for physiological data recording; these data must give information about HF deterioration early enough to predict HF-related adverse events. This work aims to evaluate seven vascular parameters for the ambulatory monitoring of congestive heart failure patients. Read More

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http://dx.doi.org/10.1007/s13239-019-00432-3DOI Listing
December 2019

Automated Detection of Vulnerable Plaque for Intravascular Optical Coherence Tomography Images.

Cardiovasc Eng Technol 2019 12 18;10(4):590-603. Epub 2019 Sep 18.

Chongqing University Cancer Hospital/Chongqing Cancer Institute/Chongqing Cancer Hospital, Chongqing, 400030, China.

Purpose: Vulnerable plaque detection is important to acute coronary syndrome (ACS) diagnosis. In recent years, intravascular optical coherence tomography (IVOCT) imaging has been used for vulnerable plaque detection. Current automated detection methods adopt the traditional image classification and object detection algorithms, such as the logistic regression model, SVM, and Haar-Adaboost, to detect vulnerable plaques. Read More

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http://dx.doi.org/10.1007/s13239-019-00425-2DOI Listing
December 2019
2 Reads

Location-Specific Comparison Between a 3D In-Stent Restenosis Model and Micro-CT and Histology Data from Porcine In Vivo Experiments.

Cardiovasc Eng Technol 2019 12 17;10(4):568-582. Epub 2019 Sep 17.

Institute for Informatics, Faculty of Science, University of Amsterdam, Amsterdam, The Netherlands.

Background: Coronary artery restenosis is an important side effect of percutaneous coronary intervention. Computational models can be used to better understand this process. We report on an approach for validation of an in silico 3D model of in-stent restenosis in porcine coronary arteries and illustrate this approach by comparing the modelling results to in vivo data for 14 and 28 days post-stenting. Read More

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http://dx.doi.org/10.1007/s13239-019-00431-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6863796PMC
December 2019
3 Reads

Optimization Framework for Patient-Specific Cardiac Modeling.

Cardiovasc Eng Technol 2019 12 17;10(4):553-567. Epub 2019 Sep 17.

Department of Mechanical Engineering, Iowa State University, Ames, IA, USA.

Purpose: Patient-specific models of the heart can be used to improve the diagnosis of cardiac diseases, but practical application of these models can be impeded by the computational costs and numerical uncertainties of fitting mechanistic models to clinical measurements from individual patients. Reliable and efficient tuning of these models within clinically appropriate error bounds is a requirement for practical deployment in the time-constrained environment of the clinic.

Methods: We developed an optimization framework to tune parameters of patient-specific mechanistic models using routinely-acquired non-invasive patient data more efficiently than manual methods. Read More

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http://dx.doi.org/10.1007/s13239-019-00428-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6868335PMC
December 2019

Embolus Transport Simulations with Fully Resolved Particle Surfaces.

Authors:
Patrick M McGah

Cardiovasc Eng Technol 2019 12 16;10(4):648-659. Epub 2019 Sep 16.

Siemens PLM Software Inc., 13810 SE Eastgate Way, Bellevue, WA, 98005, USA.

Purpose: There has been interest in recent work in using computational fluid dynamics with Lagrangian analysis to calculate the trajectory of emboli-like particles in the vasculature. While previous studies have provided an understanding of the hemodynamic factors determining the fates of such particles and their relationship to risk of stroke, most analyses have relied on a particle equation of motion that assumes the particle is "small" e.g. Read More

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http://dx.doi.org/10.1007/s13239-019-00430-5DOI Listing
December 2019

Editorial.

Cardiovasc Eng Technol 2019 09;10(3):395-396

Department of Biomedical Engineering, Ohio State University, Columbus, OH, 43210, USA.

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http://link.springer.com/10.1007/s13239-019-00429-y
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http://dx.doi.org/10.1007/s13239-019-00429-yDOI Listing
September 2019
5 Reads

On the Modeling of Patient-Specific Transcatheter Aortic Valve Replacement: A Fluid-Structure Interaction Approach.

Cardiovasc Eng Technol 2019 09 15;10(3):437-455. Epub 2019 Jul 15.

Laboratory of Biological Structure Mechanics (LaBS), Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Piazza L. da Vinci 32, 20133, Milan, Italy.

Purpose: Transcatheter aortic valve replacement (TAVR) is a minimally invasive treatment for high-risk patients with aortic diseases. Despite its increasing use, many influential factors are still to be understood and require continuous investigation. The best numerical approach capable of reproducing both the valves mechanics and the hemodynamics is the fluid-structure interaction (FSI) modeling. Read More

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http://dx.doi.org/10.1007/s13239-019-00427-0DOI Listing
September 2019
6 Reads