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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.

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.

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.

Purpose: super(18)F-FDG PET is increasingly used for imaging of vessel wall inflammation. However, limited data are available on the impact of methodological variables, i.e. prescan fasting glucose, FDG circulation time and injected FDG dose, and of different FDG uptake parameters, in vascular FDG PET imaging. Methods: Included in the study were 195 patients who underwent vascular FDG PET/CT of the aorta and the carotids. Arterial standardized uptake values ( sub(mean)SUV sub(max)), target-to-background ratios ( sub(mean)TBR sub(max)) and FDG blood-pool activity in the superior vena cava (SVC) and the jugular veins (JV) were quantified. Vascular FDG uptake values classified according to the tertiles of prescan fasting glucose levels, the FDG circulation time, and the injected FDG dose were compared using ANOVA. Multivariate regression analyses were performed to identify the potential impact of all variables described on the arterial and blood-pool FDG uptake. Results: Tertile analyses revealed FDG circulation times of about 2.5 h and prescan glucose levels of less than 7.0 mmol/l, showing a favorable relationship between arterial and blood-pool FDG uptake. FDG circulation times showed negative associations with aortic sub(mean)SUV sub(max) values as well as SVC and JV FDG blood-pool activity, but positive correlations with aortic and carotid sub(mean)TBR sub(max) values. Prescan glucose levels were negatively associated with aortic and carotid sub(mean)TBR sub(max) and carotid sub(mean)SUV sub(max) values, but were positively correlated with SVC blood-pool uptake. The injected FDG dose failed to show any significant association with vascular FDG uptake. Conclusion: FDG circulation times and prescan blood glucose levels significantly affect FDG uptake in the aortic and carotid walls and may bias the results of image interpretation in patients undergoing vascular FDG PET/CT. The injected FDG dose was less critical. Therefore, circulation times of about 2.5 h and prescan glucose levels less than 7.0 mmol/l should be preferred in this setting.

PurposePerivascular adipose tissue (PVAT) surrounds the arterial adventitia and plays an important role in vascular homeostasis. PVAT expands in obesity, and inflamed PVAT can locally promote endothelial dysfunction and atherosclerosis. Here, using adipose tissue transplantation, we tested the hypothesis that expansion of PVAT can also remotely exacerbate vascular disease.MethodsFifty milligrams of abdominal aortic PVAT was isolated from high-fat diet (HFD)-fed wild-type mice and transplanted onto the abdominal aorta of lean LDL receptor knockout mice. Subcutaneous and visceral adipose tissues were used as controls. After HFD feeding for 10 weeks, body weight, glucose/insulin sensitivity, and lipid levels were measured. Adipocytokine gene expression was assessed in the transplanted adipose tissues, and the thoracic aorta was harvested to quantify atherosclerotic lesions by Oil-Red O staining and to assess vasorelaxation by wire myography.ResultsPVAT transplantation did not influence body weight, fat composition, lipid levels, or glucose/insulin sensitivity. However, as compared with controls, transplantation of PVAT onto the abdominal aorta increased thoracic aortic atherosclerosis. Furthermore, PVAT transplantation onto the abdominal aorta inhibited endothelium-dependent relaxation in the thoracic aorta. MCP-1 and TNF-α expression was elevated, while adiponectin expression was reduced, in the transplanted PVAT tissue, suggesting augmented inflammation as a potential mechanism for the remote vascular effects of transplanted PVAT.ConclusionsThese data suggest that PVAT expansion and inflammation in obesity can remotely induce endothelial dysfunction and augment atherosclerosis. Identifying the underlying mechanisms may lead to novel approaches for risk assessment and treatment of obesity-related vascular disease.

Purpose: Giant cell arteritis (GCA) is the most common form of vasculitis in western countries. super(18)F-FDG PET has been shown to be a valuable tool for the diagnosis of extracranial GCA, but results of studies are inconsistent due to a lack of standardized super(18)F-FDG PET criteria. In this study, we compared different semiquantitative approaches using a controlled design to define the most efficient method. Methods: All patients with biopsy-proven GCA who had undergone an super(18)F-FDG PET/CT scan in our PET unit were reviewed and matched with a control group based on age and sex. Different semiquantitative arterial (ascending and descending thoracic aorta and aortic arch) to background (liver, lung and venous blood pool) SUV ratios were blindly compared between GCA patients and matched controls. Results: We included 11 patients with biopsy-proven GCA cases and 11 matched controls. There were no differences between the groups with regard to body weight, injected radioactivity, blood glucose level or CRP. The arterial to venous blood pool ratios discriminated the two groups better than other methods when applied to the aortic arch and the descending thoracic aorta (p<0.015). In particular, the highest aortic to highest blood pool SUV sub(max) ratio, when applied to the aortic arch, provided optimal diagnostic performance (sensitivity 81.8 %, specificity 91 %, AUC 0.87; p<0.0001) using a cut-off value of 1.53. Conclusion: Among all tested super(18)F-FDG PET/CT methods, the aortic to blood pool SUV sub(max) ratio outperformed the liver and lung ratios. We suggest the use of this ratio for the assessment of aortic inflammation in GCA patients.

ZusammenfassungFrauen mit bekannten Herz-Kreislauf-Erkrankungen und Kinderwunsch sollten rechtzeitig vor der Schwangerschaft eine umfassende Beratung erhalten. Diese ist als Grundlage einer informierten Entscheidungsfindung für Mütter und deren Familien unabdingbar. Des Weiteren sollte ein Behandlungsplan interdisziplinär erstellt und mit den Patientinnen besprochen werden. Zur Risikobewertung in der Schwangerschaft sollte die modifizierte Klassifikation der Weltgesundheitsorganisation (mWHO) verwendet werden. Auch wenn es sich bei Erkrankungen der Aorta um seltene Pathologien handelt, sind diese häufig lebensbedrohlich. Herzklappenerkrankungen sind häufiger. Aufgrund neuer Möglichkeiten in der Chirurgie und der Antikoagulation stellt die Therapie von Herzklappenerkrankungen eine besondere Herausforderung dar. Kardiomyopathien in der Schwangerschaft können Todesfälle und schwere kardiovaskulärer Komplikationen, wie eine fortschreitende Herzinsuffizienz oder thromboembolische Ereignisse, verursachen. Mittlerweile sind jedoch neuartige Behandlungsmöglichkeiten verfügbar.

Background In patients with bicuspid valve (BAV), ascending aorta (AAo) dilatation may be caused by altered flow patterns and wall shear stress (WSS). These differences may explain different aortic dilatation morphotypes. Using 4D-flow cardiovascular magnetic resonance (CMR), we aimed to analyze differences in flow patterns and regional axial and circumferential WSS maps between BAV phenotypes and their correlation with ascending aorta dilatation morphotype. Methods One hundred and one BAV patients (aortic diameter ≤ 45 mm, no severe valvular disease) and 20 healthy subjects were studied by 4D-flow CMR. Peak velocity, flow jet angle, flow displacement, in-plane rotational flow (IRF) and systolic flow reversal ratio (SFRR) were assessed at different levels of the AAo. Peak-systolic axial and circumferential regional WSS maps were also estimated. Unadjusted and multivariable adjusted linear regression analyses were used to identify independent correlates of aortic root or ascending dilatation. Age, sex, valve morphotype, body surface area, flow derived variables and WSS components were included in the multivariable models. Results The AAo was non-dilated in 24 BAV patients and dilated in 77 (root morphotype in 11 and ascending in 66). BAV phenotype was right-left (RL-) in 78 patients and right-non-coronary (RN-) in 23. Both BAV phenotypes presented different outflow jet direction and velocity profiles that matched the location of maximum systolic axial WSS. RL-BAV velocity profiles and maximum axial WSS were homogeneously distributed right-anteriorly, however, RN-BAV showed higher variable profiles with a main proximal-posterior distribution shifting anteriorly at mid-distal AAo. Compared to controls, BAV patients presented similar WSS magnitude at proximal, mid and distal AAo ( p  = 0.764, 0.516 and 0.053, respectively) but lower axial and higher circumferential WSS components ( p  < 0.001 for both, at all aortic levels). Among BAV patients, RN-BAV presented higher IRF at all levels ( p  = 0.024 proximal, 0.046 mid and 0.002 distal AAo) and higher circumferential WSS at mid and distal AAo ( p  = 0.038 and 0.046, respectively) than RL-BAV. However, axial WSS was higher in RL-BAV compared to RN-BAV at proximal and mid AAo ( p  = 0.046, 0.019, respectively). Displacement and axial WSS were independently associated with the root-morphotype, and circumferential WSS and SFRR with the ascending-morphotype. Conclusions Different BAV-phenotypes present different flow patterns with an anterior distribution in RL-BAV, whereas, RN-BAV patients present a predominant posterior outflow jet at the sinotubular junction that shifts to anterior or right anterior in mid and distal AAo. Thus, RL-BAV patients present a higher axial WSS at the aortic root while RN-BAV present a higher circumferential WSS in mid and distal AAo. These results may explain different AAo dilatation morphotypes in the BAV population.

To identify magnetic resonance (MR) angiography derived predictors of progressive dilatation and surgery of the aortic root in Marfan syndrome. We retrospectively included 111 patients (32.7±16.5 years, range: 7-75 years) with a total of 446 MR angiographies. Aortic diameter growth rates of the entire thoracic aorta and Z-scores were estimated from annual diameter measurements. Aortic root shape was subdivided into three different types: (T0) normal; (T1) localized dilatation; (T2) generalized aortic root dilatation. Aortic diameter, Z-score, age, and aortic root shape at baseline were tested as predictors of aortic root dilatation using a multivariate logistic regression model. The highest aortic growth rate was observed at the level of the sinuses of Valsalva. Higher aortic root diameters and Z-scores at baseline predicted an increased growth of the aortic root (p = 0.003 and p<0.001). Young age (<30 years) was a predictor for the increase of Z-scores when compared to patients ≥30 years (p = 0.019). 25/111 patients (22.5%) had a T0 aortic root shape, 59/111 patients (53.2%) had a T1 aortic root shape, and 27/111 patients (24.3%) had a T2 aortic root shape. Aortic root shape did not predict further aortic growth (p>0.05). However, significantly more patients undergoing surgery had a generalized aortic dilatation (19/28, 76.9%) than a localized aortic root dilatation (9/28, 32.1%) (p = 0.001). Larger baseline aortic root diameter and Z-score as well as young age predict solely progressive aortic root dilatation in Marfan patients. MR angiography derived type of aortic root shape does not predict aortic growth, but patients with generalized aortic root dilatation are referred more frequently for aortic surgery.