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Cardiovascular Engineering and Technology

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https://www.readbyqxmd.com/read/28382440/tetralogy-of-fallot-surgical-repair-shunt-configurations-ductus-arteriosus-and-the-circle-of-willis
#1
Senol Piskin, Gozde Unal, Ahmet Arnaz, Tayyar Sarioglu, Kerem Pekkan
In this study, hemodynamic performance of three novel shunt configurations that are considered for the surgical repair of tetralogy of Fallot (TOF) disease are investigated in detail. Clinical experience suggests that the shunt location, connecting angle, and its diameter can influence the post-operative physiology and the neurodevelopment of the neonatal patient. An experimentally validated second order computational fluid dynamics (CFD) solver and a parametric neonatal diseased great artery model that incorporates the ductus arteriosus (DA) and the full patient-specific circle of Willis (CoW) are employed...
April 5, 2017: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/28378165/correlation-of-wall-microstructure-and-heterogeneous-distributions-of-strain-in-evolving-murine-abdominal-aortic-aneurysms
#2
John S Wilson, Matthew R Bersi, Guangxin Li, Jay D Humphrey
A primary deficiency in predicting the progression and rupture-risk of abdominal aortic aneurysms (AAAs) is an inability to assign patient-specific, heterogeneous biomechanical properties to the remodelling aortic wall. Toward this end, we investigated possible correlations between three quantities having the potential for non-invasive measurement (diameter, wall thickness, and strain) and local wall microstructure within evolving experimental AAAs. AAAs were initiated in male C57BL/6J mice via in situ adventitial application of elastase and allowed to progress for 1-4 weeks...
April 4, 2017: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/28283942/comparison-of-blood-viscoelasticity-in-pediatric-and-adult-cardiac-patients
#3
M Keith Sharp, Mary Gregg, Guy Brock, Neema Nair, Sarina Sahetya, Erle H Austin, Christopher Mascio, Mark D Slaughter, George M Pantalos
Evidence is accumulating that blood flow patterns in the cardiovascular system and in cardiovascular devices do, in some instances, depend on blood viscoelasticity. Thus, to better understand the challenges to providing circulatory support and surgical therapies for pediatric and adult patients, viscous and elastic components of complex blood viscoelasticity of 31 pediatric patients were compared to those of 29 adult patients with a Vilastic-3 rheometer. A random effects model with categorical age covariates found statistically significant differences between pediatric and adult patients for log viscosity (p = 0...
March 10, 2017: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/28258544/effect-of-loss-of-heart-rate-variability-on-t-wave-heterogeneity-and-qt-variability-in-heart-failure-patients-implications-in-ventricular-arrhythmogenesis
#4
Sachin Nayyar, Muhammad A Hasan, Kurt C Roberts-Thomson, Thomas Sullivan, Mathias Baumert
Heart rate variability (HRV) modulates dynamics of ventricular repolarization. A diminishing value of HRV is associated with increased vulnerability to life-threatening ventricular arrhythmias, however the causal relationship is not well-defined. We evaluated if fixed-rate atrial pacing that abolishes the effect of physiological HRV, will alter ventricular repolarization wavefronts and is relevant to ventricular arrhythmogenesis. The study was performed in 16 subjects: 8 heart failure patients with spontaneous ventricular tachycardia [HFVT], and 8 subjects with structurally normal hearts (H Norm)...
March 3, 2017: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/28247311/elevated-serotonin-interacts-with-angiotensin-ii-to-result-in-altered-valve-interstitial-cell-contractility-and-remodeling
#5
Jessica Perez, Nancy Diaz, Ishita Tandon, Rachel Plate, Christopher Martindale, Kartik Balachandran
While the valvulopathic effects of serotonin (5HT) and angiotensin-II (Ang-II) individually are known, it was not clear how 5HT and Ang-II might interact, specifically in the context of the mechanobiological responses due to altered valve mechanics potentiated by these molecules. In this context, the hypothesis of this study was that increased serotonin levels would result in accelerated progression toward disease in the presence of angiotensin-II-induced hypertension. C57/BL6 J mice were divided into four groups and subcutaneously implanted with osmotic pumps containing: PBS (control), 5HT (2...
February 28, 2017: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/28244028/computer-based-cpr-simulation-towards-validation-of-aha-erc-guidelines
#6
Alka Rachel John, M Manivannan, T V Ramakrishnan
As per the AHA 2015 and ERC 2015 guidelines for resuscitation, chest compression depth should be between 5 and 6 cm with a rate of 100-120 compressions per minute. Theoretical validation of these guidelines is still elusive. We developed a computer model of the cardiopulmonary resuscitation (CPR) system to validate these guidelines. A lumped element computer model of the cardiovascular system was developed to simulate cardiac arrest and CPR. Cardiac output was compared for a range of compression pressures and frequencies...
February 27, 2017: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/28236165/mechanosensitive-microrna-181b-regulates-aortic-valve-endothelial-matrix-degradation-by-targeting-timp3
#7
Jack M Heath, Joan Fernandez Esmerats, Lucky Khambouneheuang, Sandeep Kumar, Rachel Simmons, Hanjoong Jo
Calcific aortic valve disease (CAVD) is a major cause of morbidity in the aging population, but the underlying mechanisms of its progression remain poorly understood. Aortic valve calcification preferentially occurs on the fibrosa, which is subjected to disturbed flow. The side-specific progression of the disease is characterized by inflammation, calcific lesions, and extracellular matrix (ECM) degradation. Here, we explored the role of mechanosensitive microRNA-181b and its downstream targets in human aortic valve endothelial cells (HAVECs)...
February 24, 2017: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/28168675/vascular-coupling-system-for-end-to-end-anastomosis-an-in-vivo-pilot-case-report
#8
Huizhong Li, Bruce Gale, Jill Shea, Himanshu Sant, Christi M Terry, Jay Agarwal
This paper presents the latest in vivo findings of a novel vascular coupling system. Vascular anastomosis is a common procedure in reconstructive surgeries and traditional hand suturing is very time consuming. The vascular coupling system described herein was designed to be used on arteries for a rapid and error-free anastomosis. The system consists of an engaging ring made from high density polyethylene using computer numerical control machining and a back ring made from polymethylmethacrylate using laser cutting...
February 6, 2017: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/28160266/investigation-of-stent-implant-mechanics-using-linear-analytical-and-computational-approach
#9
Hua Yang, Aleksandra Fortier, Kyle Horne, Atif Mohammad, Subhash Banerjee, Hai-Chao Han
Stent implants are essential in restoring normal blood flow in atherosclerotic arteries. Recent studies have shown high failure rates of stent implants in superficial femoral artery (SFA) as a result of dynamic loading environment imposed on the stent implants by the diseased arterial wall and turbulent blood flow. There are variety of stent designs and materials currently on the market however, there is no clear understanding if specific stent design is suitable with the material that is manufactured from and if this combination can sustain the life-cycle that the stent implants need to undergo once inside the artery...
February 3, 2017: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/28150145/editorial
#10
EDITORIAL
Ajit P Yoganathan
No abstract text is available yet for this article.
February 1, 2017: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/28070867/analytical-modeling-for-computing-lead-stress-in-a-novel-epicardial-micropacemaker
#11
Li Zhou, Yaniv Bar-Cohen, Raymond A Peck, Giorgio V Chirikian, Brett Harwin, Ramen H Chmait, Jay D Pruetz, Michael J Silka, Gerald E Loeb
Implantation and maintenance of a permanent cardiac pacing system in children remains challenging due to small patient size, congenital heart defects and somatic growth. We are developing a novel epicardial micropacemaker for children that can be implanted on the epicardium within the pericardial space via a minimally-invasive technique. The key design configurations include a novel open-coiled lead in which living tissue replaces the usual polymeric support for the coiled conductor. To better understand and be able to predict the behavior of the implanted lead, we performed a radiographic image-based modeling study on a chronic animal test...
March 2017: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/28070866/finite-element-analysis-of-patient-specific-mitral-valve-with-mitral-regurgitation
#12
Thuy Pham, Fanwei Kong, Caitlin Martin, Qian Wang, Charles Primiano, Raymond McKay, John Elefteriades, Wei Sun
Functional mitral regurgitation (FMR) is a significant complication of left ventricular dysfunction and strongly associated with a poor prognosis. In this study, we developed a patient-specific finite element (FE) model of the mitral apparatus in a FMR patient which included: both leaflets with thickness, annulus, chordae tendineae, and chordae insertions on the leaflets and origins on the papillary muscles. The FE model incorporated human age- and gender-matched anisotropic hyperelastic material properties, and MV closure at systole was simulated...
March 2017: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/27957718/dynamic-viscoelasticity-and-surface-properties-of-porcine-left-anterior-descending-coronary-arteries
#13
Hanna E Burton, Jenny M Freij, Daniel M Espino
The aim of this study was, for the first time, to measure and compare quantitatively the viscoelastic properties and surface roughness of coronary arteries. Porcine left anterior descending coronary arteries were dissected ex vivo. Viscoelastic properties were measured longitudinally using dynamic mechanical analysis, for a range of frequencies from 0.5 to 10 Hz. Surface roughness was calculated following three-dimensional reconstructed of surface images obtained using an optical microscope. Storage modulus ranged from 14...
March 2017: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/27873180/pledget-armed-sutures-affect-the-haemodynamic-performance-of-biologic-aortic-valve-substitutes-a-preliminary-experimental-and-computational-study
#14
Claudio Capelli, Chiara Corsini, Dario Biscarini, Francesco Ruffini, Francesco Migliavacca, Alfred Kocher, Guenther Laufer, Andrew M Taylor, Silvia Schievano, Martin Andreas, Gaetano Burriesci, Claus Rath
Surgical aortic valve replacement is the most common procedure of choice for the treatment of severe aortic stenosis. Bioprosthetic valves are traditionally sewed-in the aortic root by means of pledget-armed sutures during open-heart surgery. Recently, novel bioprostheses which include a stent-based anchoring system have been introduced to allow rapid implantation, therefore reducing the duration and invasiveness of the intervention. Different effects on the hemodynamics were clinically reported associated with the two technologies...
March 2017: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/27995570/hydrodynamic-assessment-of-aortic-valves-prepared-from-porcine-small-intestinal-submucosa
#15
Sharan Ramaswamy, Makensley Lordeus, Omkar V Mankame, Lilliam Valdes-Cruz, Steven Bibevski, Sarah M Bell, Ivan Baez, Frank Scholl
Infants and children born with severe cardiac valve lesions have no effective long term treatment options since currently available tissue or mechanical prosthetic valves have sizing limitations and no avenue to accommodate the growth of the pediatric patient. Tissue engineered heart valves (TEHVs) which could provide for growth, self-repair, infection resistance, and long-term replacement could be an ideal solution. Porcine small intestinal submucosa (PSIS) has recently emerged as a potentially attractive bioscaffold for TEHVs...
December 19, 2016: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/27995569/fourier-transform-infrared-spectroscopic-imaging-derived-collagen-content-and-maturity-correlates-with-stress-in-the-aortic-wall-of-abdominal-aortic-aneurysm-patients
#16
Rabee Cheheltani, Joseph E Pichamuthu, Jayashree Rao, Justin S Weinbaum, Mohammad F Kiani, David A Vorp, Nancy Pleshko
Abdominal aortic aneurysm (AAA) is a degenerative disease of the aorta characterized by severe disruption of the structural integrity of the aortic wall and its major molecular constituents. From the early stages of disease, elastin in the aorta becomes highly degraded and is replaced by collagen. Questions persist as to the contribution of collagen content, quality and maturity to the potential for rupture. Here, using our recently developed Fourier transform infrared imaging spectroscopy (FT-IRIS) method, we quantified collagen content and maturity in the wall of AAA tissues in pairs of specimens with different wall stresses...
December 19, 2016: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/27848221/mechanical-properties-of-high-entropy-alloy-al0-1cocrfeni-for-peripheral-vascular-stent-application
#17
Karthik Alagarsamy, Aleksandra Fortier, Mageshwari Komarasamy, Nilesh Kumar, Atif Mohammad, Subhash Banerjee, Hai-Chao Han, Rajiv S Mishra
High entropy alloys (HEAs) are new class of metallic materials with five or more principal alloying elements. Due to this distinct concept of alloying, the HEAs exhibit unique properties compared to conventional alloys. The outstanding properties of HEAs include increased strength, superior wear resistance, high temperature stability, increased fatigue properties, good corrosion, and oxidation resistance. Such characteristics of HEAs have generated significant interest among the scientific community. However, their applications are yet to be explored...
December 2016: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/27844463/fluid-structure-interaction-study-of-transcatheter-aortic-valve-dynamics-using-smoothed-particle-hydrodynamics
#18
Wenbin Mao, Kewei Li, Wei Sun
Computational modeling of heart valve dynamics incorporating both fluid dynamics and valve structural responses has been challenging. In this study, we developed a novel fully-coupled fluid-structure interaction (FSI) model using smoothed particle hydrodynamics (SPH). A previously developed nonlinear finite element (FE) model of transcatheter aortic valves (TAV) was utilized to couple with SPH to simulate valve leaflet dynamics throughout the entire cardiac cycle. Comparative simulations were performed to investigate the impact of using FE-only models vs...
December 2016: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/27743349/computational-tracking-of-shear-mediated-platelet-interactions-with-von-willebrand-factor
#19
Adam Ralph, Martin Somers, Jonathan Cowman, Bruno Voisin, Emma Hogan, Hannah Dunne, Eimear Dunne, Barry Byrne, Nigel Kent, Antonio J Ricco, Dermot Kenny, Simon Wong
The imaging of shear-mediated dynamic platelet behavior interacting with surface-immobilized von Willebrand factor (vWF) has tremendous potential in characterizing changes in platelet function for clinical diagnostics purposes. However, the imaging output, a series of images representing platelets adhering and rolling on the surface, poses unique, non-trivial challenges for software algorithms that reconstruct the positional trajectories of platelets. We report on an algorithm that tracks platelets using the output of such flow run experiments, taking into account common artifacts encountered by previously-published methods, and we derive seven key metrics of platelet dynamics that can be used to characterize platelet function...
December 2016: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/27730533/improved-blood-pressure-prediction-using-systolic-flow-correction-of-pulse-wave-velocity
#20
Jeffrey S Lillie, Alexander S Liberson, David A Borkholder
Hypertension is a significant worldwide health issue. Continuous blood pressure monitoring is important for early detection of hypertension, and for improving treatment efficacy and compliance. Pulse wave velocity (PWV) has the potential to allow for a continuous blood pressure monitoring device; however published studies demonstrate significant variability in this correlation. In a recently presented physics-based mathematical model of PWV, flow velocity is additive to the classic pressure wave as estimated by arterial material properties, suggesting flow velocity correction may be important for cuff-less non-invasive blood pressure measures...
December 2016: Cardiovascular Engineering and Technology
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