1,721,043 research outputs found
Finite Element Analysis of the Edwards Sapien Valve Implant: Toward a Patient-Specific Application.
No full textComparison and critical analysis of invariant-based models with respect to their ability in fitting human aortic valve data
No full textWith the increase of life expectancy and population average age, heart valve diseases have become more frequent, representing an always increasing percentage among cardiovascular diseases, which are the predominant cause of death in the western country. For this reason, research activities within such a context and, in particular, computer-based predictions of valve behavior are strongly motivated. Consequently, the study of the tissue mechanical response and the constitutive relationships for modeling material behavior represent crucial a aspect to be investigated in order to perform realistic simulations. The mechanical response of the aortic valve tissue depends on the contribution, composition, and interaction of different constituents, such as collagen fibers and elastin network. Accordingly, constitutive laws including non-linearity and anisotropy are necessary. Clearly, the complexity of a constitutive model increases more as it takes into account the histological structure of the tissue. Numerous constitutive models have been developed to describe arterial tissue, but relatively few models have been calibrated specifically for the aortic valve. This study focuses on the investigation of constitutive models so far proposed in the literature which could be suitable to capture the mechanical behavior of the aortic valvular tissue. To make the right choice, the comparison between these constitutive models is done in terms of the fitting quality achieved with respect to human aortic valve data proposed in the literature. For this purpose, an optimization technique based on the nonlinear least square method is used. The obtained material parameters could be later used in finite element analysis adopted, in this last decade, as an innovative approach to support the operation planning procedure and the design of artificial grafts
Simulation of transcatheter aortic valve implantation: a patient-specific finite element approach
No full textUntil recently, heart valve failure has been treated adopting open-heart surgical techniques and cardiopulmonary bypass. However, over the last decade, minimally invasive procedures have been developed to avoid high risks associated with conventional open-chest valve replacement techniques. Such a recent and innovative procedure represents an optimal field for conducting investigations through virtual computer-based simulations: in fact, nowadays, computational engineering is widely used to unravel many problems in the biomedical field of cardiovascular mechanics and specifically, minimally invasive procedures. In this study, we investigate a balloon-expandable valve and we propose a novel simulation strategy to reproduce its implantation using computational tools. Focusing on the Edwards SAPIEN valve in particular, we simulate both stent crimping and deployment through balloon inflation. The developed procedure enabled us to obtain the entire prosthetic device virtually implanted in a patient-specific aortic root created by processing medical images; hence, it allows evaluation of postoperative prosthesis performance depending on different factors (e.g. device size and prosthesis placement site). Notably, prosthesis positioning in two different cases (distal and proximal) has been examined in terms of coaptation area, average stress on valve leaflets as well as impact on the aortic root wall. The coaptation area is significantly affected by the positioning strategy (- 24%, moving from the proximal to distal) as well as the stress distribution on both the leaflets (+13.5%, from proximal to distal) and the aortic wall (- 22%, from proximal to distal). No remarkable variations of the stress state on the stent struts have been obtained in the two investigated cases
Patient-specific finite element analysis of transcatheter aortic valve implantation
No full textAortic valve stenosis represents an important public health problem which can be treated through transcatheter
aortic valve implantation. Being a quite recent technology, many aspects related to such a minimallyinvasive
procedure need further investigation (e.g., paravalvular leakage). The well-established finite element
method represents a possible technology to study such aspects within a virtual computer-based framework. Herein,
we propose a patient-specific study which includes native leaflets and calcifications with the goal of evaluating the
postoperative performance of the implanted prosthetic valv
Shape Memory Alloys: from constitutive modeling to finite element analysis of stent deployment
No full textPatient-specific Simulations in Cardiovascular Biomechanics: from Diagnosis to Prediction
No full textPatient-specific finite element analysis of carotid artery stenting: impact of constitutive vessel modeling on vessel wall stress distribution
No full text
Finite Element Analysis of Stentless Valve Implant in Patient-Specific Aortic Root Geometry.
No full text- …
