Explore the vast range of titles available.

This study investigates the regional mechanical, structural, and morphological properties of the human aorta using fresh tissues from 10 middle-aged and elderly donors (62 ± 11 years old, 30% female). Four locations were analyzed: descending thoracic aorta (TA), supraceliac aorta (SC), infrarenal aorta (IFR), and distal abdominal aorta (dAA). Planar biaxial testing revealed location-specific stiffness, with distal regions exhibiting significantly reduced stretch at physiological stress levels. At 75 kPa, the circumferential stretch decreased from 1.24 in the TA to 1.12 in the dAA, while longitudinal stretch declined from 1.18 to 1.12. Elastin density in the medial layer showed a marked reduction, decreasing from 23.5% in the TA to 8.9% in the dAA, accompanied by thinning and fragmentation of elastic lamellae distally. Glycosaminoglycans were primarily localized near the intima and exhibited a consistent density (~ 5–6%) across all locations. Morphometric analysis revealed a progressive decrease in wall thickness in load-free conditions from 3.10 mm in the TA to 2.77 mm in the dAA, while stress-free configurations highlighted greater residual stresses in distal segments. Constitutive modeling using four common constitutive relations, including a four-fiber family model, provided parameters for computational simulations, with the four-fiber model offering the best fit. These findings provide quantitative insights into location-specific variations in the human aorta, advancing our understanding of its biomechanical and structural heterogeneity and informing computational models and therapeutic approaches.

ObjectivesTo develop and evaluate a fully automatic method to measure diameters of the ascending and descending aorta on non-ECG-gated, non-contrast computed tomography (CT) scans.Material and methodsThe method combines multi-atlas registration to obtain seed points, aorta centerline extraction, and an optimal surface segmentation approach to extract the aorta surface around the centerline. From the extracted 3D aorta segmentation, the diameter of the ascending and descending aorta was calculated at cross-sectional slices perpendicular to the extracted centerline, at the level of the pulmonary artery bifurcation, and at 1-cm intervals up to 3 cm above and below this level. Agreement with manual annotations was evaluated by dice similarity coefficient (DSC) for segmentation overlap, mean surface distance (MSD), and intra-class correlation (ICC) of diameters on 100 CT scans from a lung cancer screening trial. Repeatability of the diameter measurements was evaluated on 617 baseline-one year follow-up CT scan pairs.ResultsThe agreement between manual and automatic segmentations was good with 0.95 ± 0.01 DSC and 0.56 ± 0.08 mm MSD. ICC between the diameters derived from manual and from automatic segmentations was 0.97, with the per-level ICC ranging from 0.87 to 0.94. An ICC of 0.98 for all measurements and per-level ICC ranging from 0.91 to 0.96 were obtained for repeatability.ConclusionThis fully automatic method can assess diameters in the thoracic aorta reliably even in non-ECG-gated, non-contrast CT scans. This could be a promising tool to assess aorta dilatation in screening and in clinical practice.Key Points• Fully automatic method to assess thoracic aorta diameters.• High agreement between fully automatic method and manual segmentations.• Method is suitable for non-ECG-gated CT and can therefore be used in screening.

Preterm birth is associated with higher blood pressure, which could be because preterm birth alters early aortic elastin and collagen development to cause increased arterial stiffness. We measured central and conduit artery size and multiple indices of arterial stiffness to define the extent and severity of macrovascular changes in individuals born preterm. A total of 102 young adults born preterm and 102 controls who were born after an uncomplicated pregnancy underwent cardiovascular magnetic resonance on a Siemens 1.5 T scanner to measure the aortic cross-sectional area in multiple locations. Ultrasound imaging with a Philips CX50 and linear array probe was used to measure carotid and brachial artery diameters. Carotid-femoral pulse wave velocity and the augmentation index were measured by SphygmoCor, brachial-femoral pulse wave velocity by Vicorder and aortic pulse wave velocity by cardiovascular magnetic resonance. The cardio-ankle vascular index (CAVI) was used as a measurement of global stiffness, and ultrasound was used to assess peripheral vessel distensibility. Adults born preterm had 20% smaller thoracic and abdominal aortic lumens (2.19±0.44 vs. 2.69±0.60 cm 2 , P <0.001; 1.25±0.36 vs. 1.94±0.45 cm 2 , P <0.001, respectively) but similar carotid and brachial diameters to adults born at term. Pulse wave velocity was increased (5.82±0.80 vs. 5.47±0.59 m s −1 , P <0.01, 9.06±1.25 vs. 8.33±1.28 m s −1 , P =0.01, 5.23±1.19 vs. 4.75±0.91 m s −1 , P <0.01) and carotid distensibility was decreased (4.75±1.31 vs. 5.60±1.48 mm Hg −1 10 3 , P <0.001) in this group compared with the group born at term. However, the global and peripheral arterial stiffness measured by CAVI and brachial ultrasound did not differ (5.95±0.72 vs. 5.98±0.60, P =0.80 and 1.07±0.48 vs. 1.19±0.54 mm Hg −1 10 3 , P =0.12, respectively). Adults who are born preterm have significant differences in their aortic structure from adults born at term, but they have relatively small differences in central arterial stiffness that may be partially explained by blood pressure variations.

Differences in cardiac and aortic structure and function are associated with cardiovascular diseases and a wide range of other types of disease. Here we analyzed cardiovascular magnetic resonance images from a population-based study, the UK Biobank, using an automated machine-learning-based analysis pipeline. We report a comprehensive range of structural and functional phenotypes for the heart and aorta across 26,893 participants, and explore how these phenotypes vary according to sex, age and major cardiovascular risk factors. We extended this analysis with a phenome-wide association study, in which we tested for correlations of a wide range of non-imaging phenotypes of the participants with imaging phenotypes. We further explored the associations of imaging phenotypes with early-life factors, mental health and cognitive function using both observational analysis and Mendelian randomization. Our study illustrates how population-based cardiac and aortic imaging phenotypes can be used to better define cardiovascular disease risks as well as heart–brain health interactions, highlighting new opportunities for studying disease mechanisms and developing image-based biomarkers. Using magnetic resonance images of the heart and aorta from 26,893 individuals in the UK Biobank, a phenome-wide association study associates cardiovascular imaging phenotypes with a wide range of demographic, lifestyle and clinical features.

In this study, the investigators found a strong association, in two cohorts, between future exacerbations of COPD and the ratio of the diameter of the pulmonary artery to the diameter of the aorta (with both diameters measured from a baseline CT scan) that is greater than 1. Acute exacerbations of chronic obstructive pulmonary disease (COPD) are critical events in the natural history of the disease and are associated with accelerated loss of lung function and poor quality of life. 1 , 2 Hospitalizations for exacerbations account for $18 billion in direct costs annually in the United States and are associated with 1-year mortality of 21% and 5-year mortality of 55%. 3 Identification of patients at risk for these events is therefore of major importance. Acute exacerbations of COPD are defined as an increase in dyspnea, cough, or sputum production warranting a change in therapy. These acute exacerbations often result from . . .

Objectives To generate reference values for thoracic and abdominal aortic diameters determined by magnetic resonance imaging (MRI) and analyse their association with cardiovascular risk factors in the general population. Methods Data from participants ( n  = 1759) of the Study of Health in Pomerania were used for analysis in this study. MRI measurement of thoracic and abdominal aortic diameters was performed. Parameters for calculation of reference values according to age and sex analysis were provided. Multivariable linear regression models were used for determination of aortic diameter-related risk factors, including smoking, blood pressure (BP), high-density lipoprotein cholesterol (HDL-C). Results For the ascending aorta (β = −0.049, p  < 0.001), the aortic arch (β = −0.061, p  < 0.001) and the subphrenic aorta (β = −0.018, p  = 0.004), the body surface area (BSA)-adjusted diameters were lower in men. Multivariable-adjusted models revealed significant increases in BSA-adjusted diameters with age for all six aortic segments ( p  < 0.001). Consistent results for all segments were observed for the positive associations of diastolic BP (β = 0.001; 0.004) and HDL (β = 0.035; 0.087) with BSA-adjusted aortic diameters and for an inverse association of systolic BP (β = −0.001). Conclusions Some BSA-adjusted median aortic diameters are smaller in men than in women. All diameters increase with age, diastolic blood pressure and HDL-C and decrease as systolic BP increases. Key Points • Median aortic diameter increases with age and diastolic blood pressure . • Median aortic diameter is larger in men than in women . • Some BSA-adjusted median aortic diameters are smaller in men than in women .

Diffusion Tensor Imaging is a non-invasive imaging technique based on Magnetic Resonance Imaging that provides information on the tissue microstructure from the preferential direction of water molecules’ diffusion. While the technique is widely used in neuroimaging, recent new applications were found for arterial tissue microstructure such as aorta and carotids. In the state of art, the Diffusion Tensor Imaging datasets for arterial tissues are usually acquired with ultra-high field scanners and no singular software for the processing of ex-vivo ring-like tissues is available. The present manuscript aims to demonstrate the application of a clinical magnetic resonance scanner to infer on fiber microstructure of ex-vivo arterial specimens. This was achieved by developing a custom workflow for the specific analysis of Diffusion Tensor Imaging data for arterial microstructures. First, a custom software platform was developed by including dedicated modules to perform the following processing pipeline: NIfTI conversion, eddy current correction, segmentation, estimation of diffusion tensor, diffusion parameters and fiber reconstruction and analysis. Then, a set of acquisitions was carried out on six fresh human aortic samples of ascending aorta by using a 3T clinical scanner (Philips Ingenia). The data were processed with both our Python-based custom workflow and other commercial software. The results obtained from the custom workflow were in agreement with the ones from the commercial software. Moreover, specific tools for tissue fibers visualizations and orientation analyses were added. In this study, the usefulness of the custom workflow for processing specific arterial Diffusion Tensor Imaging datasets was demonstrated. The efficacy of the processing pipeline was comparable with the other commercial software, with also the addition fiber analysis tools, specific for the vessel structure.

The neural crest is an embryonic stem cell population unique to vertebrates 1 whose expansion and diversification are thought to have promoted vertebrate evolution by enabling emergence of new cell types and structures such as jaws and peripheral ganglia 2 . Although jawless vertebrates have sensory ganglia, convention has it that trunk sympathetic chain ganglia arose only in jawed vertebrates 3 – 8 . Here, by contrast, we report the presence of trunk sympathetic neurons in the sea lamprey, Petromyzon marinus , an extant jawless vertebrate. These neurons arise from sympathoblasts near the dorsal aorta that undergo noradrenergic specification through a transcriptional program homologous to that described in gnathostomes. Lamprey sympathoblasts populate the extracardiac space and extend along the length of the trunk in bilateral streams, expressing the catecholamine biosynthetic pathway enzymes tyrosine hydroxylase and dopamine β-hydroxylase. CM-DiI lineage tracing analysis further confirmed that these cells derive from the trunk neural crest. RNA sequencing of isolated ammocoete trunk sympathoblasts revealed gene profiles characteristic of sympathetic neuron function. Our findings challenge the prevailing dogma that posits that sympathetic ganglia are a gnathostome innovation, instead suggesting that a late-developing rudimentary sympathetic nervous system may have been characteristic of the earliest vertebrates. Challenging the belief that sympathetic ganglia are an innovation of jawed vertebrates, a study reports the presence of sympathetic neurons in an extant jawless vertebrate, the sea lamprey Petromyzon marinus .

ObjectivesThe aim of this study was to evaluate whether the orientation of the heart, measured as an angle between the long axis of the heart and ascending aorta midline (heart-aorta-angle, HAA), associates with ascending aortic (AA) dilatation. Furthermore, the association between HAA and wall shear stress (WSS) was studied.MethodsHAA was retrospectively measured in 1000 consecutive coronary artery computed tomographic angiography (CCTA) images in patients with low-to-moderate pretest probability for coronary artery disease (CAD). To evaluate the effects of HAA on AA flow, 4D flow MRI was performed for 28 patients with AA dilatation (> 40 mm) and WSS was analyzed.ResultsThe mean age of patients undergoing CCTA was 52.9 ± 9.8 years; 66.5% were women. Their median HAA was 128.7° and interquartile range 123.3–134.1°. HAA was significantly smaller in patients with dilated AA (median 126.7° [121.3–130.8°]) compared with the patients with normal AA (median 129.5° [124.3–135.3°], p < 0.001). HAA was smaller in males (p < 0.001) and in patients with diabetes (p = 0.016), hypertension (p = 0.001), CAD (p = 0.003), hypercholesterolemia (p < 0.001), and bicuspid aortic valve (p = 0.025) than without these factors. In a subpopulation without any of these underlying diseases (n = 233), HAA was still significantly smaller in the patients with dilated AA (median 127.9° [124.3–134.3°]) compared with patients with normal AA (median 131.9° [127.6–136.9°], p = 0.013). In 4D flow MRI, a smaller HAA correlated with increased total WSS in the outer curvature of the proximal AA (r = − 0.510, p = 0.006).ConclusionA smaller HAA associates with AA dilatation and affects the blood flow in the proximal AA.Key Points• A smaller angle between the long axis of the heart and ascending aorta midline associated with ascending aortic dilatation.• A smaller heart-aorta-angle correlated with increased total wall shear stress in the outer curvature of the proximal ascending aorta.

Supravalvar aortic stenosis (SVAS) severity guides management, including decisions for surgery. Physiologic and technical factors limit the determination of SVAS severity by Doppler echocardiography and cardiac catheterization in Williams syndrome (WS). We hypothesized SVAS severity could be determined by the sinotubular junction-to-aortic annulus ratio (STJ:An). We reviewed all preintervention echocardiograms in patients with WS with SVAS cared for at our center. We measured STJ, An, peak and mean Doppler gradients, and calculated STJ:An. We created 2 mean gradient prediction models. Model 1 used the simplified Bernoulli's equation, and model 2 used computational fluid dynamics (CFD). We compared STJ:An to Doppler-derived and CFD gradients. We reviewed catheterization gradients and the waveforms and analyzed gradient variability. We analyzed 168 echocardiograms in 54 children (58% male, median age at scan 1.2 years, interquartile range [IQR] 0.5 to 3.6, median echocardiograms 2, IQR 1 to 4). Median SVAS peak Doppler gradient was 24 mm Hg (IQR 14 to 46.5). Median SVAS mean Doppler gradient was 11 mm Hg (IQR 6 to 21). Median STJ:An was 0.76 (IQR 0.63 to 0.84). Model 1 underpredicted clinical gradients. Model 2 correlated well with STJ:An through all severity ranges and demonstrated increased pressure recovery distance with decreased STJ:An. The median potential variability in catheterization-derived gradients in a given patient was 14.5 mm Hg (IQR 7.5 to 19.3). SVAS severity in WS can be accurately assessed using STJ:An. CFD predicts clinical data well through all SVAS severity levels. STJ:An is independent of physiologic state and has fewer technical limitations than Doppler echocardiography and catheterization. STJ:An could augment traditional methods in guiding surgical management decisions.