Search results for "Patient-specific model"
showing 10 items of 16 documents
An In Vitro Phantom Study on the Role of the Bird-Beak Configuration in Endograft Infolding in the Aortic Arch.
2015
Purpose: To assess endograft infolding for excessive bird-beak configurations in the aortic arch in relation to hemodynamic variables by quantifying device displacement and rotation of oversized stent-grafts deployed in a phantom model. Methods: A patient-specific, compliant, phantom pulsatile flow model was reconstructed from a patient who presented with collapse of a Gore TAG thoracic endoprosthesis. Device infolding was measured under different flow and pressure conditions for 3 protrusion extensions (13, 19, and 24 mm) of the bird-beak configuration resulting from 2 TAG endografts with oversizing of 11% and 45%, respectively. Results: The bird-beak configuration with the greatest protr…
Comparison of hemodynamic and structural indices of ascending thoracic aortic aneurysm as predicted by 2-way FSI, CFD rigid wall simulation and patie…
2018
Patient-specific computational modeling is increasingly being used to predict structural and hemodynamic parameters, especially when current clinical tools are not accessible. Indeed, pathophysiology of ascending thoracic aortic aneurysm (ATAA) has been simulated to quantify the risk of complications by novel prognostic parameters and thus to improve the clinical decision-making process related to the intervention of ATAAs. In this study, the relevance of aneurysmal wall elasticity in determining parameters of clinical importance, such as the wall shear stress (WSS), is discussed together with the significance of applying realistic boundary conditions to consider the aortic stretch and twis…
In Silico Shear and Intramural Stresses are Linked to Aortic Valve Morphology in Dilated Ascending Aorta
2017
Objective/Background: The development of ascending aortic dilatation in patients with bicuspid aortic valve (BAV) is highly variable, and this makes surgical decision strategies particularly challenging. The purpose of this study was to identify new predictors, other than the well established aortic size, that may help to stratify the risk of aortic dilatation in BAV patients.Methods: Using fluid-structure interaction analysis, both haemodynamic and structural parameters exerted on the ascending aortic wall of patients with either BAV ( n = 21) or tricuspid aortic valve (TAV; n = 13) with comparable age and aortic diameter (42.7 +/- 5.3 mm for BAV and 45.4 +/- 10.0 mm for TAV) were compared…
Role of computational modeling in thoracic aortic pathology: A review
2014
Thoracic aortic diseases are life-threatening conditions causing significant mortality and morbidity despite advances in diagnostic and surgical treatments. Computational methods combined with imaging techniques provide quantitative information of disease progression, which may improve clinical treatments and therapeutic strategies for clinical practice. Since hemodynamic and wall mechanics play important roles in the natural history and progression of aortic diseases, we reviewed the potential application of computational modeling of the thoracic aorta. We placed emphasis on the clinical relevance of these techniques for the assessment of aortic dissection, thoracic aortic aneurysm, and ao…
Three-dimensional cardiac computational modelling: methods, features and applications
2015
[EN] The combination of computational models and biophysical simulations can help to interpret an array of experimental data and contribute to the understanding, diagnosis and treatment of complex diseases such as cardiac arrhythmias. For this reason, three-dimensional (3D) cardiac computational modelling is currently a rising field of research. The advance of medical imaging technology over the last decades has allowed the evolution from generic to patient-specific 3D cardiac models that faithfully represent the anatomy and different cardiac features of a given alive subject. Here we analyse sixty representative 3D cardiac computational models developed and published during the last fifty …
Patient-Specific Rehearsal Feasibility Before Endovascular Repair of Ruptured Abdominal Aortic Aneurysm.
2019
Purpose: To evaluate the feasibility of a patient-specific rehearsal (PsR) before emergency endovascular aneurysm repairs (eEVAR) and its influence on the operation. Materials and Methods: From February 2016 to October 2016, 10 consecutive patients (mean age 75 +/- 7.4 years; 9 men) presenting with a ruptured abdominal aortic aneurysm (rAAA) suitable for standard EVAR were enrolled in the study. A 3-dimensional (3D) model of the abdominal aorta was generated on a virtual reality simulator based on the patient's computed tomography (CT) images. Following the patient-specific simulation setup, PsR was conducted during patient admission or in parallel with the preoperative eEVAR workup. Measur…
Three-dimensional parametric modeling of bicuspid aortopathy and comparison with computational flow predictions
2016
Bicuspid aortic valve (BAV)-associated ascending aneurysmal aortopathy (namely âbicuspid aortopathyâ) is a heterogeneous disease making surgeon predictions particularly challenging. Computational flow analysis can be used to evaluate the BAV-related hemodynamic disturbances, which likely lead to aneurysm enlargement and progression. However, the anatomic reconstruction process is time consuming so that predicting hemodynamic and structural evolution by computational modeling is unfeasible in routine clinical practice. The aim of the study was to design and develop a parametric program for three-dimensional (3D) representations of aneurysmal aorta and different BAV phenotypes starting fr…
Particle image velocimetry study of the celiac trunk hemodynamic induced by continuous-flow left ventricular assist device
2017
Abstract Whereas left ventricular assist device (LVAD) is the gold-standard therapy for patients with heart failure, gastrointestinal bleeding is one of the most common complications. LVAD implantation may remarkably impact aortic hemodynamics so that experimental and computational flow analyses can be used to study the disease mechanisms. Here we present an experimentally-calibrated computational model of the celiac trunk hemodynamic of a LVAD-supported patient who experienced bleeding after device implantation. Specifically, both particle image velocimetry (PIV) and echocardiography were used to measure and compare flow distributions in each branch of a phantom model of the patient abdomi…
Computational fluid dynamics in the assessment of patients' postoperative status after glottis-widening surgery
2017
Background. Computational fluid dynamics (CFD), a rapidly developing instrument with a number of practical applications, allows calculation and visualization of the changing parameters of airflow in the upper respiratory tract. Objectives. The aim of this study was to demonstrate the advantages of CFD as an instrument for noninvasive tests of the larynx in patients who had undergone surgical treatment due to bilateral vocal fold paralysis. Material and Methods. Surface measurements of the glottic space were made during maximum adduction of the vocal folds. Additionally, the following spirometric parameters were determined: forced vital capacity (FVC), forced expiratory volume in the first s…
Computational Fluid-Dynamic Analysis after Carotid Endarterectomy: Patch Graft versus Direct Suture Closure.
2017
Background Closure technique after carotid endarterectomy (CEA) still remains an issue of debate. Routine use of patch graft (PG) has been advocated to reduce restenosis, stroke, and death, but its protective effect, particularly from late restenosis, is less evident and recent studies call into question this thesis. This study aims to compare PG and direct suture (DS) by means of computational fluid dynamics (CFD). To identify carotid regions with flow recirculation more prone to restenosis development, we analyzed time-averaged oscillatory shear index (OSI) and relative residence time (RRT), that are well-known indices correlated with plaque formation. Methods CFD was performed in 12 pati…