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Cardiovascular Engineering and Technology

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...
October 14, 2016: Cardiovascular Engineering and Technology
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...
October 11, 2016: Cardiovascular Engineering and Technology
Napachanok Mongkoldhumrongkul, Najma Latif, Magdi H Yacoub, Adrian H Chester
Responses of valve endothelial cells (VECs) to shear stresses are important for the regulation of valve durability. However, the effect of flow patterns subjected to VECs on the opposite surfaces of the valves on the production of extracellular matrix (ECM) has not yet been investigated. This study aims to investigate the response of side-specific flow patterns, in terms of ECM synthesis and/or degradation in porcine aortic valves. Aortic and ventricular sides of aortic valve leaflets were exposed to oscillatory and laminar flow generated by a Cone-and-Plate machine for 48 h...
October 5, 2016: Cardiovascular Engineering and Technology
Yaghoub Dabiri, Janet Ronsky, Imtiaz Ali, Ameen Basha, Alisha Bhanji, Kishan Narine
Bioprosthetic aortic valves (BAVs) are becoming the prostheses of choice in heart valve replacement. The objective of this paper is to assess the effects of leaflet geometry on the mechanics and hemodynamics of BAVs in a fluid structure interaction model. The curvature and angle of leaflets were varied in 10 case studies whereby the following design parameters were altered: a circular arch, a line, and a parabola for the radial curvature, and a circular arch, a spline, and a parabola for the circumferential curvature...
August 29, 2016: Cardiovascular Engineering and Technology
Vaibhavi A Sonetha, Jayesh R Bellare
An occlusion device is placed in an abnormal opening of the heart or its surrounding vessels to regain normal blood flow. There are various occlusion devices available for treatment of various congenital heart defects like PDA, ASD, etc. However, they have limitations like residual shunting, erosion of tissue, displacement and breakage of device, thrombus formation and sudden death. To improve efficiency and to reduce failure of occlusion devices, it is important to simulate blood flow through defect before and after placement of device...
August 23, 2016: Cardiovascular Engineering and Technology
Joao S Soares, Kristen R Feaver, Will Zhang, David Kamensky, Ankush Aggarwal, Michael S Sacks
The use of replacement heart valves continues to grow due to the increased prevalence of valvular heart disease resulting from an ageing population. Since bioprosthetic heart valves (BHVs) continue to be the preferred replacement valve, there continues to be a strong need to develop better and more reliable BHVs through and improved the general understanding of BHV failure mechanisms. The major technological hurdle for the lifespan of the BHV implant continues to be the durability of the constituent leaflet biomaterials, which if improved can lead to substantial clinical impact...
August 9, 2016: Cardiovascular Engineering and Technology
Frederick J Schoen
The clinical and pathological features of the most frequent intrinsic structural diseases that affect the heart valves are well established, but heart valve disease mechanisms are poorly understood, and effective treatment options are evolving. Major advances in the understanding of the structure, function and biology of native valves and the pathobiology, biomaterials and biomedical engineering, and the clinical management of valvular heart disease have occurred over the past several decades. This communication reviews contemporary considerations relative to the pathology of valvular heart disease, including (1) clinical significance and epidemiology of valvular heart disease; (2) functional and dynamic valvular macro-, micro- and ultrastructure; (3) causes, morphology and mechanisms of human valvular heart disease; and (4) pathologic considerations in valve replacement, repair and, potentially, regeneration of the heart valves...
August 8, 2016: Cardiovascular Engineering and Technology
M Beheshti, F H Foomany, K Magtibay, S Masse, P Lai, J Asta, D A Jaffray, K Nanthakumar, S Krishnan, K Umapathy
Most existing studies of cardiac arrhythmia rely on surface measurements through optical or electrical mapping techniques. Current density imaging (CDI) is a method which enables us to study current pathways inside the tissue. However, this method entails implementation complexities for beating ex vivo hearts. Hence, this work presents an approach to simulate and study the current distributions in different cardiac electrophysiological states. The results are corroborated by experimental data, and they indicate that different states were distinguishable...
September 2016: Cardiovascular Engineering and Technology
Munirah Ismail, Gideon Praveen Kumar, Foad Kabinejadian, Yen Ngoc Nguyen, Fangsen Cui, Edgar Lik Wui Tay, Hwa Liang Leo
Heterotopic implantation of transcatheter tricuspid valve is a new treatment option for tricuspid regurgitation. Transcatheter tricuspid valves are implanted onto the cavoatrial junction in order to avoid the challenging task of anchoring the valve onto the complex tricuspid valve annulus. However, little is known about optimum extent of oversizing of the valved stent in a vena cava. In this study, we implanted valves of the same diameter onto the larger sized inferior vena cava (IVC) and a smaller sized superior vena cava (SVC)...
September 2016: Cardiovascular Engineering and Technology
Avik Basu, Zhaoming He
Annulus tension (AT) is defined as leaflet tension per unit length of the annulus circumference. AT was investigated to understand tricuspid valve (TV) annulus mechanics. Ten porcine TVs were mounted on a right ventricle rig with an annulus plate to simulate TV closure. The TVs were mounted on the annulus plate in a normal and dilated TV annulus sizes, and closed under transvalvular pressure of 40 mmHg with the annulus held peripherally by wires. Anterior papillary muscle (PM) and septal PM were displaced in the dilated annulus...
September 2016: Cardiovascular Engineering and Technology
Joshua O Taylor, Bryan C Good, Anthony V Paterno, Prasanna Hariharan, Steven Deutsch, Richard A Malinauskas, Keefe B Manning
Transitional and turbulent flow through a simplified medical device model is analyzed as part of the FDA's Critical Path Initiative, designed to improve the process of bringing medical products to market. Computational predictions are often used in the development of devices and reliable in vitro data is needed to validate computational results, particularly estimations of the Reynolds stresses that could play a role in damaging blood elements. The high spatial resolution of laser Doppler velocimetry (LDV) is used to collect two component velocity data within the FDA benchmark nozzle model...
September 2016: Cardiovascular Engineering and Technology
Brian D Plourde, Lauren J Vallez, Biyuan Sun, Brittany B Nelson-Cheeseman, John P Abraham, Cezar S Staniloae
Simulations were made of the pressure and velocity fields throughout an artery before and after removal of plaque using orbital atherectomy plus adjunctive balloon angioplasty or stenting. The calculations were carried out with an unsteady computational fluid dynamic solver that allows the fluid to naturally transition to turbulence. The results of the atherectomy procedure leads to an increased flow through the stenotic zone with a coincident decrease in pressure drop across the stenosis. The measured effect of atherectomy and adjunctive treatment showed decrease the systolic pressure drop by a factor of 2...
September 2016: Cardiovascular Engineering and Technology
Bernhard M Vennemann, Thomas Rösgen, Thierry P Carrel, Dominik Obrist
The Lapeyre-Triflo FURTIVA valve aims at combining the favorable hemodynamics of bioprosthetic heart valves with the durability of mechanical heart valves (MHVs). The pivoting region of MHVs is hemodynamically of special interest as it may be a region of high shear stresses, combined with areas of flow stagnation. Here, platelets can be activated and may form a thrombus which in the most severe case can compromise leaflet mobility. In this study we set up an experiment to replicate the pulsatile flow in the aortic root and to study the flow in the pivoting region under physiological hemodynamic conditions (CO = 4...
September 2016: Cardiovascular Engineering and Technology
Nima Mirkhani, Mohammad Reza Davoudi, Pedram Hanafizadeh, Daryoosh Javidi, Niloofar Saffarian
Numerical simulation of the bileaflet mechanical heart valves (BMHVs) has been of interest for many researchers due to its capability of predicting hemodynamic performance. A lot of studies have tried to simulate this three-dimensional complex flow in order to analyze the effect of different valve designs on the blood flow pattern. However, simplified models and prescribed motion for the leaflets were utilized. In this paper, transient complex blood flow in the location of ascending aorta has been investigated in a realistic model by fully coupled simulation...
September 2016: Cardiovascular Engineering and Technology
Ariel Greisas, Sharon Zlochiver
Cardiac fibroblast proliferation and concomitant collagenous matrix accumulation (fibrosis) develop during multiple cardiac pathologies. Recent studies have demonstrated direct electrical coupling between myocytes and fibroblasts in vitro, and assessed the electrophysiological implications of such coupling. However, in the living tissues, such coupling has not been demonstrated, and only indirect coupling via the extracellular space is likely to exist. In this study we employed a multi-domain model to assess the modulation of the cardiac electrophysiological properties by neighboring fibroblasts assuming only indirect coupling...
September 2016: Cardiovascular Engineering and Technology
Eric E Buse, Stephen L Hilbert, Richard A Hopkins, Gabriel L Converse
There are many heart valve replacements currently available on the market; however, these devices are not ideal for pediatric patients with congenital heart valve defects. Decellularized valve substitutes offer potential for improved clinical outcomes and require pre-clinical testing guidelines and testing systems suitable for non-crosslinked, biological heart valves. The objective of this study was to assess the hydrodynamic performance of intact, bioengineered pulmonary valves using a custom pulse duplicator capable of testing intact biological valved conduits...
July 21, 2016: Cardiovascular Engineering and Technology
Prashanta K Mandal, Sarifuddin, Vijaya B Kolachalama
Balloon angioplasty followed by local delivery of antiproliferative drugs to target tissue is increasingly being considered for the treatment of obstructive arterial disease, and yet there is much to appreciate regarding pharmacokinetics in arteries of non-uniform disease. We developed a computational model capable of simulating drug-coated balloon delivery to arteries of heterogeneous tissue composition comprising healthy tissue, as well as regions of fibrous, fibro-fatty, calcified and necrotic core lesions...
July 21, 2016: Cardiovascular Engineering and Technology
Hadi Mohammadi, Bret Nestor, Guy Fradet
Developing cardiac surgical skills and experience takes years of practice. Cardiac trainees need to develop technical proficiency in order to enhance quality of care and patient safety. Simulation-based models are common resources for teaching procedural skills in both undergraduate and postgraduate medical education. Suitable and accessible educational platforms can play a progressively important role in the training process for young surgeons in the area of cardiac surgery. Coronary artery bypass graft (CABG) surgery consists of a wide range of pathologic anatomies and surgical techniques...
July 20, 2016: Cardiovascular Engineering and Technology
Bryan C Good, Steven Deutsch, Keefe B Manning
No abstract text is available yet for this article.
July 6, 2016: Cardiovascular Engineering and Technology
Hengfei Cui, Desheng Wang, Min Wan, Jun-Mei Zhang, Xiaodan Zhao, Ru San Tan, Weimin Huang, Wei Xiong, Yuping Duan, Jiayin Zhou, Tong Luo, Ghassan S Kassab, Liang Zhong
The CT angiography (CTA) is a clinically indicated test for the assessment of coronary luminal stenosis that requires centerline extractions. There is currently no centerline extraction algorithm that is automatic, real-time and very accurate. Therefore, we sought to (i) develop a hybrid approach by incorporating fast marching and Runge-Kutta based methods for the extraction of coronary artery centerlines from CTA; (ii) evaluate the accuracy of the present method compared to Van's method by using ground truth centerline as a reference; (iii) evaluate the coronary lumen area of our centerline method in comparison with the intravascular ultrasound (IVUS) as the standard of reference...
June 2016: Cardiovascular Engineering and Technology
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