Search results for "Heart Valve"
showing 10 items of 138 documents
Microstructural manipulation of electrospun scaffolds for specific bending stiffness for heart valve tissue engineering
2012
Biodegradable thermoplastic elastomers are attractive for application in cardiovascular tissue construct development due to their amenability to a wide range of physical property tuning. For heart valve leaflets, while low flexural stiffness is a key design feature, control of this parameter has been largely neglected in the scaffold literature where electrospinning is being utilized. This study evaluated the effect of processing variables and secondary fiber populations on the microstructure, tensile and bending mechanics of electrospun biodegradable polyurethane scaffolds for heart valve tissue engineering. Scaffolds were fabricated from poly(ester urethane) urea (PEUU) and the deposition…
Tailoring Electrospinning Fabrication for Scaffolds for Heart Valve Tissue Engineering
2010
Previous work in controlling mechanical properties of electrospun scaffolds has largely been limited to altering the orientation of the fibrous network by either large rotational velocity or by altering the electric field during fabrication. Our lab has previously developed a technique to analyze the complete microstructural topology of electrospun scaffolds and extract key descriptors. In this project, we translated the target mandrel at varying speeds along its rotational axis in order to modify the microarchitecture without altering the fiber orientation angle. Using the algorithm mentioned above, we determined that increasing the translation speed resulted in a decrease in fiber interse…
Tomographic image processing for the morphological and metrological study of Valsalva sinuses
2012
This Phd thesis deals with the design and the use of image processing tools in order to allow a reliable and objective study of the sinuses of Valsalva which are important cavities of the aortic root. The proposed methods can be applied on cine-MR sequences and CT examinations without any change in the settings between two examinations.Firstly, we studied the morphology of this anatomical area and its constant properties in all images of the dataset. Sinuses are one of the main bright organs with limited movements. Hence a new algorithm has been designed. It detects and characterizes each bright organ by a single trajectory. Various tools of mathematical morphology are used for this step, a…
Ascending Aorta Resection and End-to-End Anastomosis: Redistribution of Wall Shear Stress Induced by a Bioprosthetic Heart Valve
2020
Although aortic resection and end-to-end anastomosis are applied to repair ascending aortic aneurysm, there is a lack of information on the late risk of post-operative complications, such as aortic dissection and aneurysmal re-dilatation. It is recognized that altered hemodynamic forces exerted on an aortic wall play an important role on dissection and aneurysm formation. We present a case in which the hemodynamic forces were investigated prior and after repair of an ascending aorta treated by resection with end-to-end anastomosis and a bioprosthetic heart valve. Post-operative wall shear stress was redistributed uniformly along the vessel circumference, and this may suggest a reduced risk …
Extracellular matrix fiber microarchitecture is region-specific in bicuspid aortic valve-associated ascending aortopathy
2016
Abstract Objective Ascending thoracic aortic aneurysm (ATAA) in patients with bicuspid aortic valve (BAV) commonly dilate asymmetrically compared with patients with tricuspid aortic valve (TAV). This discrepancy in aneurysm geometry led us to hypothesize that microarchitectural differences underlie the observed asymmetric dilatation pattern. The purpose of this study was to characterize the microarchitectural distinctions of the extracellular matrix of the 2 phenotypes with a focus on the proportion of radially oriented elastin and collagen fibers in different circumferential aortic regions. Methods Aortic tissue rings were obtained just distal to the sinotubular junction from patients with…
Multimodality imaging strategies for the assessment of aortic stenosis: Viewpoint of the heart valve clinic international database (HAVEC) group
2016
International audience; Aortic stenosis is the most frequent valvular heart disease. In aortic stenosis, therapeutic decision essentially depends on symptomatic status, stenosis severity, and status of left ventricular systolic function. Surgical aortic valve replacement or transcatheter aortic valve implantation is the sole effective therapy in symptomatic patients with severe aortic stenosis, whereas the management of asymptomatic patients remains controversial and is mainly based on individual risk stratification. Imaging is fundamental for the initial diagnostic work-up, follow-up, and selection of the optimal timing and type of intervention. The present review provides specific recomme…
The Evolution of Cardiovascular Surgery in Elderly Patient: A Review of Current Options and Outcomes
2014
Due to the increase in average life expectancy and the higher incidence of cardiovascular disease with advancing age, more elderly patients present for cardiac surgery nowadays. Advances in pre- and postoperative care have led to the possibility that an increasing number of elderly patients can be operated on safely and with a satisfactory outcome. Currently, coronary artery bypass surgery, aortic and mitral valve surgery, and major surgery of the aorta are performed in elderly patients. The data available show that most cardiac surgical procedures can be performed in elderly patients with a satisfactory outcome. Nevertheless, the risk for these patients is only acceptable in the absence of…
Feasibility of a MPR-based 3DTEE guidance protocol for transcatheter direct mitral valve annuloplasty.
2020
Objectives Several interventional approaches have been established for the treatment of severe mitral regurgitation (MR) in patients at elevated risk for surgery. Direct annuloplasty is a relatively novel option in transcatheter mitral valve repair dedicated to reverse pathology in specific subsets of MR. With regard to echocardiographic guidance, this procedure presents with higher efforts in comparison with edge-to-edge therapy to enable safe and exact positioning of the device's anchors; evidence on optimal peri-interventional imaging is sparse. We tested a specific 3D-echo-guidance protocol implementing single-beat multiplanar reconstruction (MPR) and evaluated its feasibility. Methods …
Simulation of left ventricular outflow tract (LVOT) obstruction in transcatheter mitral valve-in-ring replacement.
2020
Left ventricular outflow tract (LVOT) obstruction is a feared complication of transcatheter mitral valve replacement (TMVR). This procedure leads to an elongation of LVOT in the left ventricle (namely, the neoLVOT), ultimately portending hemodynamic impairment and death. This study sought to understand the biomechanical implications of LVOT obstruction in two patients who underwent TMVR as an "off-label" application of the Edwards SAPIEN 3 (S3) Ultra transcatheter heart valve (THV). A computational framework of TMVR was developed to assess the neoLVOT area and quantify the sub-aortic flow structure. We observed that the annuloplasty ring serves as the key anchor zone of S3 Ultra THV. A good…
The Revolution in Heart Valve Therapy: Focus on Novel Imaging Techniques in Intra-Procedural Guidance
2021
Transcatheter valvular interventions have undergone significant progress over the last years with novel treatment options in even complex valvular conditions. In conjunction with this development, ...