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Background: Ascending thoracic aortic aneurysm (ATAA) is a silent and threatening dilation of the ascending aorta (AscAo). Maximal aortic diameter which is currently used for ATAA patients management and surgery planning has been shown to inadequately characterize risk of dissection in a large proportion of patients. Our aim was to propose a comprehensive quantitative evaluation of aortic morphology and pressure-flow-wall associations from four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) data in healthy aging and in patients with ATAA., Methods: We studied 17 ATAA patients (64.7 ± 14.3 years, 5 females) along with 17 age- and sex-matched healthy controls (59.7 ± 13.3 years, 5 females) and 13 younger healthy subjects (33.5 ± 11.1 years, 4 females). All subjects underwent a CMR exam, including 4D flow and three-dimensional anatomical images of the aorta. This latter dataset was used for aortic morphology measurements, including AscAo maximal diameter (iD MAX ) and volume, indexed to body surface area. 4D flow MRI data were used to estimate 1) cross-sectional local AscAo spatial (∆P S ) and temporal (∆P T ) pressure changes as well as the distance (∆D PS ) and time duration (∆T PT ) between local pressure peaks, 2) AscAo maximal wall shear stress (WSS MAX ) at peak systole, and 3) AscAo flow vorticity amplitude (V MAX ), duration (V FWHM ), and eccentricity (V ECC )., Results: Consistency of flow and pressure indices was demonstrated through their significant associations with AscAo iD MAX (WSS MAX :r = -0.49, p < 0.001; V ECC :r = -0.29, p = 0.045; V FWHM :r = 0.48, p < 0.001; ∆D PS :r = 0.37, p = 0.010; ∆T PT :r = -0.52, p < 0.001) and indexed volume (WSS MAX :r = -0.63, V ECC :r = -0.51, V FWHM :r = 0.53, ∆D PS :r = 0.54, ∆T PT :r = -0.63, p < 0.001 for all). Intra-AscAo cross-sectional pressure difference, ∆P S , was significantly and positively associated with both V MAX (r = 0.55, p = 0.002) and WSS MAX (r = 0.59, p < 0.001) in the 30 healthy subjects (48.3 ± 18.0 years). Associations remained significant after adjustment for iD MAX , age, and systolic blood pressure. Superimposition of ATAA patients to normal aging trends between ∆P S and WSS MAX as well as V MAX allowed identifying patients with substantially high pressure differences concomitant with AscAo dilation., Conclusion: Local variations in pressures within ascending aortic cross-sections derived from 4D flow MRI were associated with flow changes, as quantified by vorticity, and with stress exerted by blood on the aortic wall, as quantified by wall shear stress. Such flow-wall and pressure interactions might help for the identification of at-risk patients., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Nadjia Kachenoura reports financial support was provided by Fondation pour la recherche Médicale. Sophia Houriez–Gombaud-Saintonge reports a relationship with ESME Sudria that includes employment. Nadjia Kachenoura reports a relationship with ECOS SUD that includes funding grants. The other authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Thoracic aorta calcium (TAC) can be assessed from cardiac computed tomography (CT) studies to improve cardiovascular risk prediction. The aim of this study was to develop a fully automatic system to detect TAC and to evaluate its performance for classifying the patients into four TAC risk categories. The method started by segmenting the thoracic aorta, combining three UNets trained with axial, sagittal and coronal CT images. Afterwards, the surrounding lesion candidates were classified using three combined convolutional neural networks (CNNs) trained with orthogonal patches. Image datasets included 1190 non-enhanced ECG-gated cardiac CT studies from a cohort of cardiovascular patients (age 57 ± 9 years, 80% men, 65% TAC > 0). In the test set (N = 119), the combination of UNets was able to successfully segment the thoracic aorta with a mean volume difference of 0.3 ± 11.7 ml (<6%) and a median Dice coefficient of 0.947. The combined CNNs accurately classified the lesion candidates and 87% of the patients (N = 104) were accurately placed in their corresponding risk categories (Kappa = 0.826, ICC = 0.9915). TAC measurement can be estimated automatically from cardiac CT images using UNets to isolate the thoracic aorta and CNNs to classify calcified lesions., (© 2024 IOP Publishing Ltd.)

Arterial calcification is an independent predictor of cardiovascular disease (CVD) events whereas thoracic aorta calcium (TAC) detection might anticipate extracoronary outcomes. In this work, we trained six convolutional neural networks (CNNs) to detect aortic calcifications and to automate the TAC score assessment in intermediate CVD risk patients. Cardiac computed tomography images from 1415 patients were analyzed together with their aortic geometry previously assessed. Orthogonal patches centered in each aortic candidate lesion were reconstructed and a dataset with 19,790 images (61% positives) was built. Three single-input 2D CNNs were trained using axial, coronal and sagittal patches together with two multi-input 2.5D CNNs combining the orthogonal patches and identifying their best regional combination (BRC) in terms of lesion location. Aortic calcifications were concentrated in the descending (66%) and aortic arch (26%) portions. The BRC of axial patches to detect ascending or aortic arch lesions and sagittal images for the descending portion had the best performance: 0.954 F1-Score, 98.4% sensitivity, 87% of the subjects correctly classified in their TAC category and an average false positive TAC score per patient of 30. A CNN that combined axial and sagittal patches depending on the candidate aortic location ensured an accurate TAC score prediction.

Objectives: In the ascending aorta, calcification density was independently and inversely associated with cardiovascular disease (CVD) risk prediction. Until now, the density of thoracic aorta calcium (TAC) was estimated as the Agatston score divided by the calcium area (D AG ). We thought to analyze TAC density in a full Hounsfield unit (HU) range and to study its association with TAC volume, traditional risk factors, and CVD events., Methods: Non-enhanced CT images of 1426 patients at intermediate risk were retrospectively reviewed. A calcium density score was estimated as the average of the maximum HU attenuation in all calcified plaques of the entire thoracic aorta (D AV )., Results: During a mean 4.0 years follow-up, there were 26 events for a total of 674 patients with TAC > 0. TAC volume and D AV were positively correlated (R = 0.72). The median D AV value was 457 HU (IQ 323-603 HU) and was exponentially related to D AG (R = 0.86). D AV was inversely associated with systolic pressure (p < 0.05), pulse pressure (p < 0.01), hypertension (p < 0.05), and 10-year FRS (p < 0.001) after adjusting for TAC volume. When TAC volume and D AV were included in a logistic model, a significant improvement was shown in CVD risk estimation beyond coronary artery calcium (CAC) (AUC = 0.768 vs 0.814, p < 0.05). In multivariable Cox models, TAC volume and D AV showed an independent association with CVD., Conclusions: In intermediate risk patients, TAC density was inversely associated with several risk factors after adjustment for TAC volume. A significant improvement was observed over CAC when TAC volume and density were added into the risk prediction model., Key Points: • Calcifications in the aorta can be non-invasively assessed using CT images • A higher calcium score is associated with a higher cardiovascular risk • Measuring the calcifications size and the density separately can improve the risk prediction.

Objectives: Pulse wave velocity (PWV) of the aortic arch is usually estimated by using 2D phase contrast in MRI. Thanks to 4D flow MRI, segmental PWV of the ascending and descending aorta, as well as PWV of the entire thoracic aorta can now be estimated within the same examination. Our objective is to compare PWVs obtained by 2D and 4D PC, through their relationships with carotid-femoral PWV (cf-PWV), age and left ventricular remodelling., Basic Methods: MRI examinations were performed at 3 Tesla, including 2D PC acquisitions with through-plane velocity encoding and sagittal 4D phase contrast acquisitions covering the thoracic aorta volume. PWVs were calculated after estimating aortic lengths and flow transit times between the ascending aorta and descending aorta in 2D and between valve, isthmus and diaphragm in 4D resulting in 2D-PWV, 4D-TA-PWV; 4D-AA-PWV, 4D-DA-PWV., Main Results: Fifty-seven healthy volunteers (25 men, age 51 years ± 17) were studied. All MRI-PWVs were correlated with cf-PWV (r = 0.67; r = 0.63: r = 0.47; r = 0.61 for 2D-PWV, 4D-TA-PWV; 4D-AA-PWV, 4D-DA-PWV, respectively, P < 0.001). 2D-PWV and 4D-TA-PWV were strongly related with age (r = 0.76 and r = 0.77, respectively). The highest correlation, between left ventricular thickness or LV mass/end diastolic volume (EDV) ratio and segmental PWVs of the thoracic aorta was found with 4D-AA-PWV (r = 0.43, P < 0.01 and r = 0.48, P < 0.01)., Principal Conclusions: Global and segmental PWV analysis of the thoracic aorta can be accurately assessed using 4D flow MRI. 4D-PWVs were highly correlated with ageing and cf-PWV. The strong association between the ascending aorta stiffness and the left ventricular remodelling in healthy volunteers is encouraging to better estimate left ventricular afterload.

Objective: To evaluate an automatic correction method for velocity offset errors in cardiac 4D-flow acquisitions., Materials and Methods: Velocity offset correction was done in a plane-by-plane scheme and compared to a volumetric approach. Stationary regions were automatically detected. In vitro experiments were conducted in a phantom using two orientations and two encoding velocities (Venc). First- to third-order models were fit to the time-averaged images of the three velocity components. In vivo experiments included realistic ROIs in a volunteer superimposed to a phantom. In 15 volunteers, blood flow volume of the proximal and distal descending aorta, of the pulmonary artery (Qp) and the ascending aorta (Qs) was compared., Results: Offset errors were reduced after correction with a third-order model, yielding residual phantom velocities below 0.6 cm/s and 0.4% of Venc. The plane-by-plane correction method was more effective than the volumetric approach. Mean velocities through superimposed ROIs of a volunteer vs phantom were highly correlated (r 2  = 0.96). The significant difference between proximal and distal descending aortic flows was decreased after correction from 8.1 to - 1.4 ml (p < 0.001) and Qp/Qs reduced from 1.08 ± 0.09 to 1.01 ± 0.05., Discussion: An automatic third-order model corrected velocity offset errors in 4D-flow acquisitions, achieving acceptable levels for clinical applications.

Aims: Risk models that use a single aortic diameter threshold have failed to successfully predict acute type B aortic dissection (TBAD). We sought to identify meaningful age-indexed anatomical variables to predict TBAD risk., Methods and Results: A geometric deformable model, consisting of virtual elastic balloons that inflate inside a vessel lumen, was developed to quantify thoracic aorta geometry. In the presence of TBAD, true and total artery lumen morphology were assessed. A stepwise logistic model was built to predict TBAD risk. Initial covariates included age, gender, body mass index and all anatomic variables not directly related to the dissected segment. Patients with acute TBAD (n=34, 62±12years old, 57% male gender) were compared with subjects with symptoms of dissection, but with a subsequent negative diagnosis (n=51, 62±12years old, 76% male gender). Patient risk factors did not differ between groups. Most aortic anatomical variables were age-dependent. Aortic size was larger in every segment of the dissected with respect to non-dissected aortas (p<0.001). Variables entering the TBAD risk prediction model were aortic arch diameter, thoracic aorta length and age (predictability=0.9764, r=0.85), confirmed by a bootstrap internal validation. In dissected aortas, the true lumen volume was correlated to age (r=0.72)., Conclusions: TBAD probability increases with a larger aortic arch diameter and a longer thoracic aorta, whereas threshold values increase with age. The aortic morphology was age-dependent. After dissection, true lumen volume correlated to age. The use of threshold values indexed to age should be encouraged to better prevent and eventually treat TBAD., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Introduction and Objectives: Thoracic aorta calcium detection is known to improve cardiovascular risk prediction for cardiac and noncardiac events beyond traditional risk factors. We investigated the influence of thoracic aorta morphometry on the presence and extent of aortic calcifications., Methods: Nonenhanced computed tomography heart scans were performed in 970 asymptomatic participants at increased cardiovascular risk. An automated algorithm estimated the geometry of the entire thoracic aorta and quantified the aortic calcium Agatston score. A nonparametric model was used to analyze the percentiles of calcium score by age. Logistic regression models were calculated to identify anatomical associations with calcium levels., Results: Calcifications were concentrated in the aortic arch and descending portions. Higher amounts of calcium were associated with an enlarged, unfolded, less tapered and more tortuous aorta. The size of the ascending aorta was not correlated with aortic calcium score, whereas enlargement of the descending aorta had the strongest association: the risk of having a global calcium score > 90th percentile was 3.62 times higher (confidence interval, 2.30-5.91; P < .001) for each 2.5-mm increase in descending aorta diameter. Vessel taper, tortuosity, unfolding and aortic arch and descending volumes were also correlated with higher amounts of calcium., Conclusions: Thoracic aorta calcium was predominantly found at the arch and descending aorta and was positively associated with the size of the descending aorta and the aortic arch, but not with the size of the ascending aorta. These findings suggest that aortic dilatation may have different mechanisms and may consequently require different preventive strategies according to the considered segments., (Copyright © 2016 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.)

Objective: Thoracic aorta calcium (TAC) is measurable on the same computed tomography (CT) scan as coronary artery calcium (CAC) but has still unclear clinical value. We assessed TAC and CAC relations with non-cardiac vascular events history in a cohort of subjects at risk for cardiovascular disease., Methods: We analyzed retrospectively 1000 consecutive subjects having undergone CAC detection by non-contrast multi-slice CT with measurement field longer than usual in order to measure total TAC including aortic arch calcium. We also determined partial TAC restricted to ascending and descending thoracic aorta sites by removing arch calcium from total TAC. Calcium deposits were measured with a custom made software using Agatston score., Results: Compared with the rest of the cohort, the 30 subjects with non-cardiac vascular event history had higher median values [95% CI] of total TAC (282 [28-1809] vs 39 [0-333], p < 0.01) and partial TAC (4 [0-284] vs 0 [0-5], p < 0.01) but no different value of CAC (73 [0-284] vs 16 [0-148]). Odds ratio [95% CI] of having non-cardiac vascular event per 1-SD increase in log-transformed calcium value was significant for total TAC but not for CAC, if total TAC and CAC were entered separately (1.56 [1.12-2.24], p < 0.01 and 1.13 [0.86-1.50], respectively) or together (1.57 [1.10-2.32], p < 0.01 and 0.98 [0.73-1.32], respectively) in the logistic adjusted model., Conclusion: TAC assessment simultaneous with CAC detection provides complementary information on the extra coronary component of cardiovascular risk beyond CAC's coronary risk prediction. Further studies are required to prospectively confirm this result., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Purpose: Diagnosis and management of thoracic aorta (TA) disease demand the assessment of accurate quantitative information of the aortic anatomy. We investigated the principal modes of variation in aortic 3-dimensional geometry paying particular attention to the curvilinear portion., Materials and Methods: Images were obtained from extended noncontrast multislice computed tomography scans, originally intended for coronary calcium assessment. The ascending, arch, and descending aortas of 500 asymptomatic patients (57 ± 9 y, 81% male) were segmented using a semiautomated algorithm that sequentially inscribed circles inside the vessel cross-section. Axial planes were used for the descending aorta, whereas oblique reconstructions through a toroid path were required for the arch. Vessel centerline coordinates and the corresponding diameter values were obtained. Twelve size and shape geometric parameters were calculated to perform a principal component analysis., Results: Statistics revealed that the geometric variability of the TA was successfully explained using 3 factors that account for ∼80% of total variability. Averaged aortas were reconstructed varying each factor in 5 intervals. Analyzing the parameter loadings for each principal component, the dominant contributors were interpreted as vessel size (46%), arch unfolding (22%), and arch symmetry (12%). Variables such as age, body size, and risk factors did not substantially modify the correlation coefficients, although some particular differences were observed with sex., Conclusions: We conclude that vessel size, arch unfolding, and symmetry form the basis for characterizing the variability of TA morphology. The numerical data provided in this study as supplementary material can be exploited to accurately reconstruct the curvilinear shape of normal TAs.

The aorta plays a major role in the cardiovascular system and its function and structure are primarily affected by aging, eating habits, life style and other cardiovascular risk factors, inducing increased stiffness which is associated with cardiovascular and cerebral morbi-mortality. Our objective was to develop and validate a robust subject-specific one-dimensional wave propagation numerical model of the descending aorta. This model with a cross-sectional area, velocity and pressure formulation is built using geometric and hemodynamic data measured on a specific person and is validated against in vivo data acquired on the same subject at three distinct anatomical locations along the thoracic aorta. We studied seven healthy volunteers, who underwent carotid applanation tonometry and aortic cardiovascular magnetic resonance (CMR). Responses of our model in terms of changes in central pressure waveform with arterial alterations were consistent with previously described physiological knowledge. Quantitative validation averaged over the three descending aortic locations and the seven subjects provided low rms errors (given in percentage of the maximal clinical value) between simulated and CMR data, i.e. area: 10±6%, velocity: 11±3%, flow rate: 9±3%. Finally, we also found low rms (5±2%) when comparing simulated pressure in the proximal aortic location against tonometric carotid pressure curves. In conclusion, this simple model performs similar to more complex models of the entire systemic arterial tree at a fraction of the cost, and could be of major usefulness in the non-invasive and local estimation of proximal biomechanical and hemodynamic indices., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

A pixel-wise method for absolute and local aortic pressures estimation using 3D velocities in MRI and carotid pressure curves to set-up reference pressure values is presented. This method is based on the Navier-Stokes equation and a fast iterative algorithm. Its reliability was demonstrated: 1) in a synthetic phantom by comparison against simplified Bernoulli equation applied at peak velocities, and 2) in a healthy subject and a patient with aortic coarctation, in which absolute pressure distribution within the aortic arch was consistent with established physiopathological knowledge. Such local absolute aortic pressures may be useful in the understanding of hemodynamic changes secondary to cardiovascular alterations. Also, their addition to the already available indices of risk of aortic complications such as dilatation and dissection definition may prove of major clinical usefulness.

Aging produces a simultaneous thoracic aorta (TA) enlargement and unfolding. We sought to analyze the impact of hypertension on these geometric changes. Non-contrast computed tomography images were obtained from coronary artery calcium scans, including the entire aortic arch, in 200 normotensive and 200 hypertensive asymptomatic men. An automated algorithm reconstructed the vessel in three-dimensions, estimating orthogonal aortic sections along the whole TA pathway, and calculated several geometric descriptors to assess TA morphology. Hypertensive patients were older with respect to normotensive (P<0.001). Diameter and volume of TA ascending, arch and descending segments were higher in hypertensive patients with respect to normotensive (P<0.001) and differences persisted after adjustment for age. Hypertension produced an accelerated unfolding effect on TA shape. We found increments in aortic arch width (P<0.001), radius of curvature (P<0.001) and area under the arch curve (P<0.01) with a concomitant tortuosity decrease (P<0.05) and no significant change in aortic arch height. Overall, hypertension produced an equivalent effect of 2-7-years of aging. In multivariate analysis adjusted for age and hypertension treatment, diastolic pressure was more associated to TA size and shape changes than systolic pressure. These data suggest that hypertension accelerates TA enlargement and unfolding deformation with respect to the aging effect.

An increasing number of intermediate risk asymptomatic subjects benefit from measures of atherosclerosis burden like coronary artery calcification studies with non-contrast heart computed tomography (CT). However, additional information can be derived from these studies, looking beyond the coronary arteries and without exposing the patients to further radiation. We report a semi-automatic method that objectively assesses ascending, arch and descending aorta dimension and shape from non-contrast CT datasets to investigate the effect of aging on thoracic aorta geometry. First, the segmentation process identifies the vessel centerline coordinates following a toroidal path for the curvilinear portion and axial planes for descending aorta. Then, reconstructing oblique planes orthogonal to the centerline direction, it iteratively fits circles inside the vessel cross-section. Finally, regional thoracic aorta dimensions (diameter, volume and length) and shape (vessel curvature and tortuosity) are calculated. A population of 200 normotensive men was recruited. Length, mean diameter and volume differed by 1.2 cm, 0.13 cm and 21 cm(3) per decade of life, respectively. Aortic shape uncoiled with aging, reducing its tortuosity and increasing its radius of curvature. The arch was the most affected segment. In conclusion, non-contrast cardiac CT imaging can be successfully employed to assess thoracic aorta 3D morphometry.

Objectives: We sought to define age-related geometric changes of the aortic arch and determine their relationship to central aortic stiffness and left ventricular (LV) remodeling., Background: The proximal aorta has been shown to thicken, enlarge in diameter, and lengthen with aging in humans. However, no systematic study has described age-related longitudinal and transversal remodeling of the aortic arch and their relationship with LV mass and remodeling., Methods: We studied 100 subjects (55 women, 45 men, average age 46 ± 16 years) free of overt cardiovascular disease using magnetic resonance imaging to determine aortic arch geometry (length, diameters, height, width, and curvature), aortic arch function (local aortic distensibility and arch pulse wave velocity [PWV]), and LV volumes and mass. Radial tonometry was used to calculate central blood pressure., Results: Aortic diameters and arch length increased significantly with age. The ascending aorta length increased most, with age leading to aortic arch widening and decreased curvature. These geometric changes of the aortic arch were significantly related to decreased ascending aortic distensibility, increased aortic arch PWV (p < 0.001), and increased central blood pressures (p < 0.001). Increased ascending aortic diameter, lengthening, and decreased curvature of the aortic arch (unfolding) were all significantly associated with increased LV mass and concentric remodeling independently of age, sex, body size, and central blood pressure (p < 0.01)., Conclusions: Age-related unfolding of the aortic arch is related to increased proximal aortic stiffness in individuals without cardiovascular disease and associated with increased LV mass and mass-to-volume ratio independent of age, body size, central pressure, and cardiovascular risk factors., (Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Purpose: To investigate the efficiency of a new method (TT-Upslope) for transit time (Δt) estimation from cardiovascular MR (CMR) velocity curves., Materials and Methods: Fifty healthy volunteers (40 ± 15 years) underwent applanation tonometry to estimate carotid-femoral pulse wave velocity (cf-PWV) and carotid pressure measurements, and CMR to estimate aortic arch-PWV and ascending aorta distensibility (AAD). The Δt was calculated with TT-Upslope by minimizing the area delimited by two sigmoid curves fitted to the systolic upslope of the ascending (AAC) and descending (DAC) aorta velocity curves, and compared with previously described methods: TT-Point using the half maximum of AAC and DAC, TT-Foot using AAC and DAC feet, and TT-Wave by minimizing the area between AAC and DAC curves using cross correlation., Results: All the Δt methods provided a high reproducibility of arch-PWV. However, TT-Upslope and TT-Wave resulted in better correlations with aging (r = 0.83/r = 0.83 versus r = 0.47/r = 0.72), cf-PWV (r = 0.69/r = 0.70 versus r = 0.34/r = 0.59), and AAD (r = 0.81/r = 0.71 versus r = 0.61/r = 0.60). Furthermore, TT-Upslope resulted in stronger relationship between arch-PWV and AAD according to a theoretical model and provided better characterization of older subjects compared with TT-Wave., Conclusion: Arch-PWV estimated with CMR using the TT-Upslope method was found to be reproducible and accurate, providing strong correlations with age and aortic stiffness indices., (Copyright © 2011 Wiley-Liss, Inc.)

The strain values extracted from steady-state free-precession (SSFP) and phase contrast (PC) images acquired with a 1.5T scanner on a compliant flow phantom and within the thoracic aorta of 52 healthy subjects were compared. Aortic data were acquired perpendicular to the aorta at the level of the pulmonary artery bifurcation. Cross sectional areas were obtained by using an automatic and robust segmentation method. While a good correlation (r = 0.99) was found between the aortic areas extracted from SSFP and PC sequences, a lower correlation (r = 0.71) was found between the corresponding aortic strain values. Strain values estimated using SSFP and PC sequences were equally correlated with age. Interobserver reproducibility was better for SSFP than for PC. Strain values in the ascending and descending aorta were better correlated for SSFP (r = 0.8) than for PC (r = 0.65) and fitted with the expectation of a larger strain in the ascending aorta when using SSFP. The spatial and temporal resolutions of the acquisitions had a minor influence upon the estimated strain values. Thus, if PC acquisitions can be used to estimate both pulse wave velocity and aortic strain, an additional SSFP sequence may be useful to improve the accuracy in estimating the aortic strain., (Copyright © 2010 Wiley-Liss, Inc.)

Objectives: We analyzed, in above-average risk asymptomatic individuals, the factors determining early thoracic aorta enlargement., Methods: Ascending aortic diameter (AAD) was measured with noncontrast multidetector computed tomography in 345 participants (mean age 56 years; 78% men) without cardiovascular disease. We analyzed the associations of AAD with risk factors and Framingham risk score (FRS), multidetector computed tomography-assessed coronary artery calcium (CAC), and ultrasound interrogation of plaque presence at five sites (right and left carotid arteries, right and left femoral arteries, and abdominal aorta), the number of diseased sites with presence of plaque being counted from 0 to 5., Results: AAD was positively associated with age (P < 0.001), male sex (P < 0.01), body surface area (BSA; P < 0.001), hypertension (P < 0.001), systolic and diastolic blood pressures in individuals without antihypertensive medication (P < 0.05, P < 0.01), and FRS (P < 0.001). AAD was positively associated with CAC score after adjusting for age, sex, and BSA (P < 0001) or for FRS and BSA (P < 0.001). AAD was higher in the presence of three, four, or five than in the presence of no, one, or two diseased sites with plaque, after adjusting for age, sex, and BSA (P < 0.05) or for FRS and BSA (P < 0.001). When participants were divided into subsets by AAD tertiles and by number of sites with plaque, FRS and CAC score were greatest in individuals with AAD top tertile and 3-5 sites with plaque and lowest in those with AAD bottom tertile and 0-2 sites with plaque (P < 0.001)., Conclusion: These findings suggest that thoracic ascending aorta dilatation is related to hypertension and represents a part of a generalized atherosclerotic process of the entire vasculature.

Objective: We sought to investigate the mechanism whereby a particular deformity of the aortic arch, an angulated Gothic shape, might lead to hypertension late after anatomically successful repair of aortic coarctation., Methods: Fifty-five normotensive patients with anatomically successful repair of aortic coarctation and either a Gothic (angulated) or a Romanesque (smooth and rounded) arch were studied with magnetic resonance angiography and flow mapping in both the ascending and descending aortas. Systolic waveforms, central aortic stiffness, and pulse velocity were measured. We hypothesized that arch angulation would result in enhanced systolic wave reflection with loss of energy across the aortic arch, as well as increased central aortic stiffness., Results: Twenty patients were found to have a Gothic, and 35 a Romanesque, arch. Patients with a Gothic arch showed markedly augmented systolic wave reflection (12 +/- 6 vs 5 +/- 0.3 mL, P < .001) and greater loss of systolic wave height in the distal aorta (30% +/- 16% vs 22% +/- 12%, P < .01) compared with that of subjects with a Romanesque arch. Pulse wave velocity was also increased with a Gothic arch (5.6 +/- 1.1 vs 4.1 +/- 1 m/s, P < .0001), as well as left ventricular mass index (85 +/- 15 vs 77 +/- 20 g/m2). Patients with a Romanesque arch had increased aortic stiffness compared with that of control subjects (stiffness beta-index, 3.9 +/- 0.9 vs 2.9 +/- 1; P = .03)., Conclusions: Angulated Gothic aortic arch is associated with increased systolic wave reflection, as well as increased central aortic stiffness and left ventricular mass index. These findings explain (at least in part) the association between this pattern of arch geometry and late hypertension at rest and on exercise in subjects after coarctation repair.

Objectives: This study was designed to investigate the influence of aortic arch geometry on vascular remodeling after anatomically successful repair of coarctation of the aorta (CoA)., Background: Abnormalities of the precoarctation vasculature are known to occur after CoA repair and appear related to adverse outcomes. The influence of aortic arch geometry on such abnormalities is unknown., Methods: Sixty-three postcoarctectomy subjects (age 15.9 +/- 6.3 years) were compared with 63 control volunteers. Aortic arch shape was characterized on magnetic resonance imaging using both qualitative classification, identifying 3 subtypes of arch geometry (Gothic, Crenel, Romanesque), and a quantitative index, height/width ratio (H/W) of the aorta. Using ultrasound, we measured carotid artery intima-media thickness (IMT) and stiffness index and distensibility, as well as right brachial artery flow-mediated dilation (FMD) and glyceryl trinitate (GTN)-induced dilatation, to assess the precoarctation vasculature of these subjects., Results: Gothic arch type was associated with higher carotid IMT and stiffness index, lower carotid distensibility (p < 0.001 for all), and lower brachial reactivity (FMD, p < 0.01; GTN response, p < 0.001) compared with Crenel and Romanesque geometries and with control subjects. The height/width ratio was also significantly related to these vascular abnormalities. Even in CoA subjects with Romanesque arch geometry, arterial function and stiffness parameters were significantly impaired compared with control subjects., Conclusions: In young adult survivors of anatomically successful CoA repair, a gothic-type aortic arch with high H/W is associated with abnormal IMT, higher aortic stiffness index, and impaired arterial reactivity in the pre-CoA vasculature.

Post-operative deformation of the aortic arch architecture is associated with an increased risk of hypertension following correction of coarctation. In addition to morphological analysis, MRI allows a functional analysis of the thoracic aorta. We report three examples which illustrate the direct relationship between aortic arch morphology and blood flow in the thoracic aorta.

The mechanisms of secondary hypertension after repair of coarctation of the aorta are not well understood. Abnormalities of the architecture of the aortic arch and their consequences on blood pressure have not been studied. In order to study the relationship between abnormalities or aortic arch architecture and resting blood pressure ninety-four patients without re-coarctation were followed up prospectively from 1997 to 2004 (mean age 16.9 +/- 8.1 years; mean weight 57.5 +/- 18.3 Kg; interval since surgery 16.3 +/- 5.4 years). All underwent MRI angiography of the thoracic aorta which enabled the abnormalities to be classified in 3 groups: gothic arch, crenellated arch and roman arch. Twenty-four patients (25.5%) were hypertensive and 70 (74.4%) normotensive. There were 40 gothic arches (42.5%). 14 crenellated arches (15%) and 40 roman arches (42.5%). Gothic arches were more commonly observed in the hypertensive patients (18/40, [45%, 95% CI 31-62]) than the crenellated arches (4/14, [28.5%, 95% CI 7-48]) or the roman arches (2/40, [5%, 95% CI 2-12]). Only the gothic arch was independently correlated with hypertension on multivariate analysis. The authors conclude that gothic deformation of the aortic arch is an independent predictive factor of hypertension in patients operated for coarctation with an excellent result on the isthmic region. Patients with a gothic appearance of their aortic arch should be followed up closely.

Aims: To investigate the role of the geometry of the aortic arch in resting hypertension after successful repair of coarctation (CoA)., Methods and Results: 105 patients (15.3+/-6 years) with successful repair of aortic CoA underwent blood pressure (BP) measurements at rest and magnetic resonance imaging (MRI) of the aortic arch and left ventricle. Three categories of aortic arch shape were defined based on the global geometry of the aortic arch: gothic, crenel and normal. The ratio of the maximum height/transverse diameter of the aortic arch (A/T), the percentage of residual stenosis (RS), the growth index of the aortic arch segments (GIA), and the left ventricular mass index (LVMI) were calculated. Twenty-seven (25.7%) patients had hypertension (HT). HT was more frequent in patients with gothic arch geometry (20/44, 45.5%) than in crenel geometry (5/18, 27.8%) and in normal geometry (2/43, 4.6%) (P<0.001). Resting systolic BP and LVMI were significantly higher with gothic arch geometry. In multivariate analysis, the only correlates to HT, to level of systolic BP or to LVMI were A/T and gothic arch geometry., Conclusion: Gothic geometry of the aortic arch is associated with resting hypertension in patients having undergone successful repair of CoA. This raises concern about methods to harmoniously repair CoA in order to prevent or delay rest hypertension in adulthood.

A method for estimating pressure gradients from MR images is demonstrated. Making the usual assumption that the flowing medium is a Newtonian fluid, and with appropriate boundary conditions, the inertial forces (or acceleration components of the flow) are proportional to the pressure gradients. The technique shown here is based on an evaluation of the inertial forces from Fourier acceleration encoding. This method provides a direct measurement of the total acceleration defined as the sum of the velocity derivative vs. time and the convective acceleration. The technique was experimentally validated by comparing MR and manometer pressure gradient measurements obtained in a pulsatile flow phantom. The results indicate that the MR determination of pressure gradients from an acceleration measurement is feasible with a good correlation with the true measurements (r = 0.97). The feasibility of the method is demonstrated in the aorta of a normal volunteer. Magn Reson Med 44:66-72, 2000., (Copyright 2000 Wiley-Liss, Inc.)