Search results for "Thoracic"

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…

Assessment of Thoracic Aortic Dimensions in an Experimental Setting: Comparison of Different Unenhanced Magnetic Resonance Angiography Techniques Wit…

2008

PURPOSE To compare different unenhanced magnetic resonance angiography (MRA) techniques for quantitative evaluation of vessel lumen in an experimental setting in young pigs whose dimensions allow for a comparison with a pediatric population. MATERIAL AND METHODS Magnetic resonance imaging was performed in 5 healthy ventilated pigs at 1.5 T. Three different electrocardiogram (ECG)-triggered sequences were applied for MRA: [TSE-Db] T2-weighted dark-blood TurboSpinEcho (2.0 x 1.1 x 4 mm3); [trueFISP] 2D-steady-state-free-precession (2.2 x 1.8 x 2 mm3); [NAV] respiratory-gated, T2-prepared 3D-trueFISP (1.3 x 1.3 x 1.3 mm3). ECG-gated-CT angiography (CTA) (16-row CT, 1 mm collimation) served as …

DISSECTION PROPERTIES OF ANEURYSMAL AND NONANEURYSMAL HUMAN ASCENDING THORACIC AORTA: PRELIMINARY RESULTS

2010

Ascending thoracic aortic aneurysm (ATAA) is among the most devastating forms of cardiovascular disease, causing a significant mortality despite current medical and surgical treatments [1]. Moreover these therapies themselves are associated with great risk of mortality or morbidity, complicated by the advanced age of the typical patient, and high surgical costs. The mechanics of spontaneous aortic dissection is not fully understood. It is generally believed that aortic dissection initiates as an intimal tear in which a separation of wall layers produces the formation of a ‘false’ lumen. The dissection may propagate axially and/or circumferentially due to blood flow and pressure. Dissection …

Association of Fiber Orientation and Dissection Properties of Ascending Thoracic Aortic Aneurysms With Aortic Valve Morphology

2011

Type A aortic dissection (AoD) of an ascending thoracic aortic aneurysm (ATAA) is a life-threatening cardiovascular emergency with a high potential for death. Despite improved surgical techniques, the morbidity risk for emergent surgery remains 24% worldwide according to data from the International Registry of Acute Aortic Dissection [1].Copyright © 2011 by ASME

Diagnosis of aortic dissection by transesophageal echocardiography.

1984

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…

Regurgitant flow in apparently normal valve prostheses: improved detection and semiquantitative analysis by transesophageal two-dimensional color-cod…

1990

In 128 patients with apparently normally functioning prosthetic valves ( n = 136) in the aortic position ( n = 79) and the mitral position ( n = 57), the prevalence of transprosthetic regurgitant flow was studied by use of transthoracic and transesophageal two-dimensional color-coded Doppler echocardiography. With the transthoracic approach, regurgitant flow was detected in early systole or diastole for 28% of the mitral prostheses and for 29% of the aortic prostheses. With transesophageal color-coded Doppler echocardiography, regurgitant jets were visualized for 95% of the mitral prostheses and for 44% of the aortic prostheses. In 40% of the Bjork-Shiley prostheses and 88% of the St. Jude …

Focus on the unique mechanisms involved in thoracic aortic aneurysm formation in bicuspid aortic valve versus tricuspid aortic valve patients: clinic…

2013

OBJECTIVES: The involvement of different factors in the onset of thoracic aortic aneurysm (TAA) in patients with a bicuspid aortic valve (BAV) vs those with a tricuspid aortic valve (TAV) is well recognized. However, the molecular, genetic and cellular mechanisms driving TAA remain unclear. The aim of this study was to identify the different mechanisms involved in TAA development in patients with BAV vs TAV. METHODS: Aorta specimens and DNA samples were collected from 24 BAV (18 men and 6 women; mean age: 54.2 ± 14.39 years) and 110 TAV (79 men and 31 women, mean age: 66 ± 9.8 years) patients. A control group of 128 subjects (61 men and 67 woman, mean age: 61.1 ± 5.8 years) was also enrolle…

Treatment of isolated ascending aortic aneurysm by off-pump epiaortic wrapping is safe and durable.

2016

OBJECTIVES: Isolated ascending aortic aneurysm (iAA) is usually treated by open graft repair requiring sternotomy, cardiopulmonary bypass (CPB) and cardioplegia. This approach carries significant mortality in older patients or those presenting with comorbidities. We report an original series of patients presenting with iAA and treated with epiaortic wrapping by using a synthetic mesh. This less invasive aortic repair technique allows reducing the aortic diameter to a predefined value and is performed without CPB. METHODS: Data from patients presenting with an iAA and treated with the wrapping technique (WT) by polypropylene/polyester mesh from November 2006 to July 2015 were collected. The …

Difference in hemodynamic and wall stress of ascending thoracic aortic aneurysms with bicuspid and tricuspid aortic valve.

2012

The aortic dissection (AoD) of an ascending thoracic aortic aneurysm (ATAA) initiates when the hemodynamic loads exerted on the aneurysmal wall overcome the adhesive forces holding the elastic layers together. Parallel coupled, two-way fluid–structure interaction (FSI) analyses were performed on patient-specific ATAAs obtained from patients with either bicuspid aortic valve (BAV) or tricuspid aortic valve (TAV) to evaluate hemodynamic predictors and wall stresses imparting aneurysm enlargement and AoD. Results showed a left-handed circumferential flow with slower-moving helical pattern in the aneurysm's center for BAV ATAAs whereas a slight deviation of the blood flow toward the anterolater…