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Cardiovascular Engineering and Technology

Iman Manavitehrani, Pegah Ebrahimi, Irene Yang, Sean Daly, Aaron Schindeler, Akshat Saxena, David G Little, David F Fletcher, Fariba Dehghani, David S Winlaw
Despite advances in modern surgery, congenital heart disease remains a medical challenge and major cause of infant mortality. Valved conduits are routinely used to surgically correct blood flow in hearts with congenital malformations by connecting the right ventricle to the pulmonary artery (RV-PA). This review explores the current range of RV-PA conduits and describes their strengths and disadvantages. Homografts and xenografts are currently the primary treatment modalities, however both graft types have limited biocompatibility and durability, and present a disease transmission risk...
February 14, 2019: Cardiovascular Engineering and Technology
Shelly Singh-Gryzbon, Andrew W Siefert, Eric L Pierce, Ajit P Yoganathan
In the interventional treatment of tricuspid valve regurgitation, the majority of prosthetic devices interact with or are implanted to the tricuspid valve annulus. For new transcatheter technologies, there exists a growing body of clinical experience, literature, and professional discourse related to the difficulties in delivering, securing, and sustaining the function of these devices within the dynamic tricuspid annulus. Many of the difficulties arise from circumstances not encountered in open-heart surgery, namely; a non-arrested heart, indirect visualization, and a reliance on non-suture-based methods...
February 12, 2019: Cardiovascular Engineering and Technology
N Pinho, L C Sousa, C F Castro, C C António, M Carvalho, W Ferreira, R Ladeiras-Lopes, N D Ferreira, P Braga, N Bettencourt, S I S Pinto
PURPOSE: Coronary artery geometry can have a significant impact in the hemodynamic behavior of coronary blood flow, influencing atherosclerotic plaque formation. The present work focuses on, through a statistical study, the connection between several geometric parameters of the right coronary artery-ostium cross-sectional area, angles between the common trunk and the side-branches, tortuosity, curvature and cross-sectional area in each side-branch-and their influence on hemodynamic descriptors...
February 6, 2019: Cardiovascular Engineering and Technology
Meng Ma, Xiaohui Ma, Jie Cui, Yifeng Guo, Xiuqin Tang, Chuanmin Chen, Ying Zhu, Chao Cui, Gang Wang
PURPOSE: This study aims to investigate the effects and the molecular mechanism of cyclosporin A (CsA) against oxidative stress injury in cultured neonatal rat cardiomyocytes. METHODS: Bax/Bcl-2, cl-casp-9/casp-9, cl-casp-3/casp-3, and iNOS/β-actin ratios and p-IκB and IκB levels were analyzed by western blot. IL-1β and TNF-α levels were analyzed by ELISA. RESULTS: CsA effectively improved the cell viability and reduced the extracellular lactate dehydrogenase release in cardiomyocytes after H2 O2 -induced oxidative damage...
February 6, 2019: Cardiovascular Engineering and Technology
Thomas W Secord, Milad C Audi
PURPOSE: Energy harvesting from cardiac motion is an attractive means to avoid the use of batteries in implantable sensors and pacemakers. A single implantable device would ideally integrate both sensing and self-powering functionality. METHODS: This work describes a novel electromagnetic system that achieves high sensitivity detection of the heart rate while simultaneously providing adaptive energy harvesting capability using a tunable resonance cantilever mechanism...
February 1, 2019: Cardiovascular Engineering and Technology
K Gayathri, K Shailendhra
PURPOSE: To explore if there are any adverse effects on blood flow in human beings when they are exposed to high or ultra high intensity magnetic fields in MRI, by investigating both qualitatively and quantitatively the effects of such fields on the velocity of blood and medically significant hemodynamic wall parameters such as wall shear stress (WSS), oscillatory shear index (OSI) and relative residence time (RRT) in four human large arteries. METHODS: Blood flow in an artery is approximated as a flow through a uniform circular tube with rigid porous walls and the well-known McDonalds model is employed by using pressure gradient waveforms reported in the medical literature...
January 28, 2019: Cardiovascular Engineering and Technology
Xiang Shen, Hongfei Zhu, Jiabao Jiang, Yongquan Deng, Song Ji
PURPOSE: Recent studies suggested that suboptimal delivery and longitudinal stent deformation can result in in-stent restenosis. Therefore, the purpose of this paper was to study the effect of stent geometry on stent flexibility and longitudinal stiffness (LS) and optimize the two metrics simultaneously. Then, the reliable and accurate relationships between metrics and design variables were established. METHODS: A multi-objective optimization method based on finite element analysis was proposed for the investigation and improvement of stent flexibility and LS...
January 23, 2019: Cardiovascular Engineering and Technology
K M Aarnink, F R Halfwerk, S A M Said, J G Grandjean, J M J Paulusse
PURPOSE: Heart failure is increasingly prevalent in the elderly. Treatment of patients with heart failure aims at improving their clinical condition, quality of life, prevent hospital (re)admissions and reduce mortality. Unfortunately, only a select group of heart failure patients with reduced ejection fraction are eligible for Cardiac Resynchronization Therapy where 30-40% remain non-responders and need left ventricular support. The aim of this study is to investigate if a shape memory alloy (SMA) is able to increase the ejection fraction of a mono-chamber static heart model by 5%...
January 9, 2019: Cardiovascular Engineering and Technology
Marcus Granegger, Hitendu Dave, Walter Knirsch, Bente Thamsen, Martin Schweiger, Michael Hübler
PURPOSE: Effective treatment of patients with terminal heart failure and preserved ejection fraction (HFpEF) is an unmet medical need. The aim of this study was to investigate a novel valveless pulsatile pump as a therapeutic option for the HFpEF population through comprehensive in silico investigations. METHODS: The pump was simulated in a numerical model of the cardiovascular system of four HFpEF phenotypes and compared to a typical case of heart failure with reduced ejection fraction (HFrEF)...
December 10, 2018: Cardiovascular Engineering and Technology
T Y Qiu, L G Zhao, M Song
PURPOSE: The study compared the mechanical behavior of bioresorbable polymeric stents with various designs during deployment, and investigated their fatigue performance under pulsatile blood pressure loading. METHODS: Finite element simulations have been carried out to compare the mechanical performance of four bioresorbable polymeric stents, i.e., Absorb, Elixir, Igaki-Tamai and RevaMedical, during deployment in diseased artery. Tri-folded balloon was modelled to expand the crimped stent onto the three-layered arterial wall with plaque...
December 10, 2018: Cardiovascular Engineering and Technology
Andres Ceballos, Ray Prather, Eduardo Divo, Alain J Kassab, William M DeCampli
INTRODUCTION: The hybrid Norwood (HN) is a relatively new first stage palliative procedure for neonates with hypoplastic left heart syndrome, in which a sustainable uni-ventricular circulation is established in a less invasive manner than with the standard Norwood procedure. A computational multiscale model of the circulation following the HN procedure was used to obtain detailed hemodynamics. Implementation of a reverse-BT shunt (RBTS), a synthetic bypass from the main pulmonary to the innominate artery placed to counteract aortic arch stenosis, and its effects on local and global hemodynamics were studied...
December 4, 2018: Cardiovascular Engineering and Technology
Jenny M Freij, Hanna E Burton, Daniel M Espino
PURPOSE: This study aimed to develop an objective method for the elastic characterisation of pre- and post-transitional moduli of left anterior descending (LAD) porcine coronary arteries. METHODS: Eight coronary arteries were divided into proximal, middle and distal test specimens. Specimens underwent uniaxial extension up to 3 mm. Force-displacement measurements were used to determine the induced true stress and stretch for each specimen. A local maximum of the stretch-true stress data was used to identify a transition point...
November 28, 2018: Cardiovascular Engineering and Technology
M M Alloush, M Liermann, A Zedan, G F Oweis
PURPOSE: Peristaltic pumps (PP) are favored in flow bioreactors for their non-contact sterile design. But they produce pulsatile flow, which is consequential for the cultured cells. A novel pulse damper (PD) is reported for pulsatility elimination. METHODS: The PD design was implemented to target static pressure pulsatility and flow rate (velocity) pulsatility from a PP. Damping effectiveness was tested in a macro-scale, closed-loop recirculating bioreactor mimicking the aortic arch at flow rates up to (4 L/min)...
November 28, 2018: Cardiovascular Engineering and Technology
Brent A Craven, Kenneth I Aycock, Keefe B Manning
PURPOSE: The embolus trapping performance of inferior vena cava (IVC) filters critically depends on how emboli flow through the IVC and, thereby, on the underlying hemodynamics. Most previous studies of IVC hemodynamics have used computational fluid dynamics (CFD), but few have validated their results by comparing with quantitative experimental measurements of the flow field and none have validated in an anatomical model of the IVC that includes the primary morphological features that influence the hemodynamics (iliac veins, infrarenal curvature, and non-circular vessel cross-section)...
November 16, 2018: Cardiovascular Engineering and Technology
David A Steinman, Francesco Migliavacca
No abstract text is available yet for this article.
November 12, 2018: Cardiovascular Engineering and Technology
Maureen B Gallagher, Kenneth I Aycock, Brent A Craven, Keefe B Manning
PURPOSE: Although many previous computational fluid dynamics (CFD) studies have investigated the hemodynamics in the inferior vena cava (IVC), few studies have compared computational predictions to experimental data, and only qualitative comparisons have been made. Herein, we provide particle image velocimetry (PIV) measurements of flow in a patient-averaged IVC geometry under idealized conditions typical of those used in the preclinical evaluation of IVC filters. METHODS: Measurements are acquired under rest and exercise flow rate conditions in an optically transparent model fabricated using 3D printing...
November 8, 2018: Cardiovascular Engineering and Technology
Anna Maria Tango, Jacob Salmonsmith, Andrea Ducci, Gaetano Burriesci
PURPOSE: The understanding of the optimum function of the healthy aortic valve is essential in interpreting the effect of pathologies in the region, and in devising effective treatments to restore the physiological functions. Still, there is no consensus on the operating mechanism that regulates the valve opening and closing dynamics. The aim of this study is to develop a numerical model that can support a better comprehension of the valve function and serve as a reference to identify the changes produced by specific pathologies and treatments...
November 7, 2018: Cardiovascular Engineering and Technology
Fredrik E Fossan, Jacob Sturdy, Lucas O Müller, Andreas Strand, Anders T Bråten, Arve Jørgensen, Rune Wiseth, Leif R Hellevik
PURPOSE: The main objectives of this study are to validate a reduced-order model for the estimation of the fractional flow reserve (FFR) index based on blood flow simulations that incorporate clinical imaging and patient-specific characteristics, and to assess the uncertainty of FFR predictions with respect to input data on a per patient basis. METHODS: We consider 13 patients with symptoms of stable coronary artery disease for which 24 invasive FFR measurements are available...
October 31, 2018: Cardiovascular Engineering and Technology
Alessandro Boccadifuoco, Alessandro Mariotti, Katia Capellini, Simona Celi, Maria Vittoria Salvetti
PURPOSE: Computational fluid dynamics (CFD) and 4D-flow magnetic resonance imaging (MRI) are synergically used for the simulation and the analysis of the flow in a patient-specific geometry of a healthy thoracic aorta. METHODS: CFD simulations are carried out through the open-source code SimVascular. The MRI data are used, first, to provide patient-specific boundary conditions. In particular, the experimentally acquired flow rate waveform is imposed at the inlet, while at the outlets the RCR parameters of the Windkessel model are tuned in order to match the experimentally measured fractions of flow rate exiting each domain outlet during an entire cardiac cycle...
October 24, 2018: Cardiovascular Engineering and Technology
Effat Soleimani, Manijhe Mokhtari-Dizaji, Nasser Fatouraee, Hazhir Saberi
PURPOSE: We developed a modified Kelvin model so that the periodic changes of the arterial intima-media thickness (IMT) over the cardiac cycle were involved. Modified model was implemented for carotid artery, solved via a parameter optimization technique and biomechanical parameters of the model. METHODS: Consecutive ultrasonic images of the common carotid artery of 30 male patients including 10 healthy subjects, 10 subjects with mild and 10 subjects with sever stenosis were recorded and processed offline...
October 24, 2018: Cardiovascular Engineering and Technology
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