Search results for "Ascending Aorta"
showing 10 items of 73 documents
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…
Deep learning approach for the segmentation of aneurysmal ascending aorta.
2020
Diagnosis of ascending thoracic aortic aneurysm (ATAA) is based on the measurement of the maximum aortic diameter, but size is not a good predictor of the risk of adverse events. There is growing interest in the development of novel image-derived risk strategies to improve patient risk management towards a highly individualized level. In this study, the feasibility and efficacy of deep learning for the automatic segmentation of ATAAs was investigated using UNet, ENet, and ERFNet techniques. Specifically, CT angiography done on 72 patients with ATAAs and different valve morphology (i.e., tricuspid aortic valve, TAV, and bicuspid aortic valve, BAV) were semi-automatically segmented with Mimic…
Constitutive modeling of ascending thoracic aortic aneurysms using microstructural parameters.
2016
Ascending thoracic aortic aneurysm (ATAA) has been associated with diminished biomechanical strength and disruption in the collagen fiber microarchitecture. Additionally, the congenital bicuspid aortic valve (BAV) leads to a distinct extracellular matrix structure that may be related to ATAA development at an earlier age than degenerative aneurysms arising in patients with the morphological normal tricuspid aortic valve (TAV). The purpose of this study was to model the fiber-reinforced mechanical response of ATAA specimens from patients with either BAV or TAV. This was achieved by combining image-analysis derived parameters of collagen fiber dispersion and alignment with tensile testing dat…
Chronic atrial fibrillation in presence of aortic stenosis in a patient with polysplenia syndrome.
2013
We report a rare case of “situs viscerum ambiguous” with polysplenia syndrome, in a 69 year old female patient with aortic stenosis and chronic atrial fibrillation. The presenting symptom was dyspnoea on moderate exertion and an ECG showed supra ventricular arrhythmia. Patients trans-thoracic echocardiogram revealed a dilated left atrium, reduced ejection fraction, mild tricuspid regurgitation, moderate-severe pulmonary hypertension and severe aortic stenosis. The patient was successfully treated with a replacement of her aortic valve and ascending aorta.
Three-Dimensional Echocardiographic Evaluation of Aortic and Mitral Valve Stenosis
2001
Dynamic volume rendered three-dimensional echocardiography allows the spatial recognition of anatomy and function of the aortic and mitral valves with acceptable image quality. The aortic valve can be best visualized in a view from the ascending aorta down to the valve level, thus allowing an overview of the aortic aspect of the valve in a surgeon's perspective in ∼ 80% of patients. Planimetric measurement of the aortic valve area was possible in 88% of patients, and there is no systematic overestimation or underestimation of aortic valve area compared with two-dimensional echocardiography and catheterization. The entire valvular circumference of the mitral valve can be assessed from both a…
Tissue and circulating miRNAs as biomarkers in bicuspid aortic valve disease.
2019
Recent data suggested that bicuspid aortic valve (BAV) with left-right (L-R), right-non coronary (R-NC) and left-non coronary (L-NC) cusp fusion represents distinct pathological entities1. The rate of aortic enlargement varies according to the pattern of cusps fusion, with faster rates of aortic sinus and ascending aortic dilatation associated with the L-R compared to R-NC and L-NC morphology. In our study, we sought to investigate the histological fea-tures of aneurysms associated to different BAV phenotypes and we looked for specific mi-croRNAs (miRNA) as biomarkers of medial degeneration severity in order to optimize surgi-cal indication and prevent catastrophic complications such as rup…
Systematische Analyse der Geometrie eines definierten Kontrastmittelbolus - Implikationen für die kontrastmittelverstärkte 3D-MR-Angiographie thoraka…
2005
Purpose: Little is known about the dispersion of a defined contrast bolus during its passage through the heart and pulmonary vasculature. The purpose of this study was to analyze factors influencing a defined contrast bolus for ce-MRA of thoracic vessels. Materials and Methods: For analysis of bolus geometry, an ECG-gated saturation-recovery Turbo-Flash sequence with a TI of 20 msec was used. It was acquired axially at the level of the pulmonary trunc, so that with one data acquisition a curve analysis was possible in the ascending and descending aorta, and in the pulmonary trunc. Twenty-nine patients received 3 ml of Gd-DTPA diluted with saline to a total of 20 ml. Contrast injection was d…
Erfahrungen mit einer 3D-Navigatorsequenz zur Koronargefäßdarstellung an einem Hochleistungs-MR-System
2002
Purpose: To evaluate MR coronary angiography using a three-dimensional navigator echo sequence on a MR scanner with a high performance gradient system. Material and Methods: Five healthy volunteers were examined with a 1.5 Tesla MR system, using a high performance prototype gradient system (peak amplitude 50 mT/m, rising time 600 μs). For imaging, a navigated gradient-echo pulse sequence with an in-plane resolution between 0.63 × 0.63 and 0.78 × 0.78 mm 2 was used. Per patient two overlapping slabs were acquired. The number of visualised coronary artery segments was estimated (AHA classification). In addition, signal-to-noise measurements were performed in the ascending aorta at the level o…
Polyamines and microbiota in bicuspid and tricuspid aortic valve aortopathy
2019
Polyamines are small aliphatic cationic molecules synthesized via a highly regulated pathway and involved in general molecular and cellular phenomena. Both mammalian cells and microorganisms synthesize polyamines, and both sources may contribute to the presence of polyamines in the circulation. The dominant location for microorganisms within the body is the gut. Accordingly, the gut microbiota probably synthesizes most of the polyamines in the circulation in addition to those produced by the mammalian host cells. Polyamines are mandatory for cellular growth and proliferation. Established evidence suggests that the polyamine spermidine prolongs lifespan and improves cardiovascular health in …
Local Application of Leptin Antagonist Attenuates Angiotensin II–Induced Ascending Aortic Aneurysm and Cardiac Remodeling
2016
Background Ascending thoracic aortic aneurysm ( ATAA ) is driven by angiotensin II (Ang II ) and contributes to the development of left ventricular ( LV ) remodeling through aortoventricular coupling. We previously showed that locally available leptin augments Ang II ‐induced abdominal aortic aneurysms in apolipoprotein E–deficient mice. We hypothesized that locally synthesized leptin mediates Ang II ‐induced ATAA . Methods and Results Following demonstration of leptin synthesis in samples of human ATAA associated with different etiologies, we modeled in situ leptin expression in apolipoprotein E–deficient mice by applying exogenous leptin on the surface of the ascending aorta. This treatm…