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| (A) Representative images of medial layer in the inner and outer curves. Scale bars, 500 µm. (B,C) Media thickness of the inner and outer curves of dilated AA with TAV (B) and BAV (C). (D) Correlation was detected between media thickness and failure strain in all patients with TAA. (E) Moderate to severe media degeneration was observed in TAA patients. (F,G) Correlations were detected between maximum total WSS and media degeneration (F) and elastin density (G). (H) Correlation was detected between elastin density and failure strain in all patients with TAA. p-values < ### 0.001. Non-parametric test.
Source publication
Objectives: In thoracic aortic aneurysm (TAA) of the ascending aorta (AA), AA is progressively dilating due to the weakening of the aortic wall. Predicting and preventing aortic dissections and ruptures in TAA continues to be challenging, and more accurate assessment of the AA dilatation, identification of high-risk patients, and timing of repair s...
Contexts in source publication
Context 1
... correlations between WSS and failure stress, failure strain, and dynamic modulus depict that the higher total and lower circumferential WSS ratio predict that TAA is more susceptible to rupture (Figures 3G-I). Figure 4D). No difference was detected in controls. ...
Context 2
... difference was detected in controls. Moderate to severe media degeneration was observed in most TAA patients ( Figure 4E, Supplementary Figures S2A,B). However, no difference was detected between the inner and outer curves. ...
Context 3
... in TAV patients, elastin density was significantly decreased in the outer curves (p = 0.012) (Supplementary Figure S2C). Correlations between WSS and media degeneration or elastin density depicted that lower WSS predicts more severe pathological changes of the AA (Figures 4F,G). As expected, reduced elastin level led to a weakened aortic wall and lower failure strain ( Figure 4H). ...
Context 4
... between WSS and media degeneration or elastin density depicted that lower WSS predicts more severe pathological changes of the AA (Figures 4F,G). As expected, reduced elastin level led to a weakened aortic wall and lower failure strain ( Figure 4H). FIGURE 3 | (A-F) Boxplots of the biomechanical properties for dilated AA with TAV or BAV, and healthy subjects with median and outliers (a cross mark). ...
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Objectives
Indication for Reduction of Ascending Aortoplasty (RAA) and long-term outcomes remain unclear. This study analyzed the outcomes after nonreinforced RAA in two Austrian centers.
Methods
Patients with RAA at two Austrian centers between 6/2,009 and 6/2,017 were retrospectively analyzed. Aortic diameters were measured by CT pre- and post-o...
Citations
... Guo et al. [6] reported a mean ascending aortic diameter related to acute dissection of 42.6 mm. The interaction of molecular proteins with the cellular and intercellular matrix is claimed to be related to the progression of aortic diameter [7][8][9]. ...
... The body mass index (BMI) reduction combined with appropriate pharmacotherapy directed on cardiovascular risk modification can help reduce the aortic dilatation rate [44]. Aortic aneurysm is characterized by active processes, including local inflammatory activation [6,8,45]. Endothelial dysfunction as an early pathologic event in aneurysm formation is claimed to contribute to either oxidative stress or inflammatory degeneration of the arterial wall [46]. ...
... Moreover, both higher PWV and higher VEL suggested an increased risk of cardiac function insufficiency in patients with TAAA and AAA. Regarding the tendency of aortic dilation, WSS is considered to be a classic hemodynamic marker and has been verified in multiple studies (32,33). Evidence suggests that after decomposition into two directions, both axial and circumferential WSS can independently predict proximal descending aorta dilation beyond clinical factors (34). ...
Background
Thoracoabdominal aortic aneurysms (TAAAs) are rare but complicated aortic pathologies that can result in high morbidity and mortality. The whole-aorta hemodynamic characteristics of TAAA survivors remains unknown. This study sought to obtain a comprehensive view of flow hemodynamics of the whole aorta in patients with TAAA using four-dimensional flow (4D flow) magnetic resonance imaging (MRI).
Methods
This study included patients who had experienced TAAA or abdominal aortic aneurysm (AAA) and age- and sex-matched volunteers who had attended China Hospital from December 2021 to December 2022 in West. Patients with unstable ruptured aneurysm or other cardiovascular diseases were excluded. 4D-flow MRI that covered the whole aorta was acquired. Both planar parameters [(regurgitation fraction (RF), peak systolic velocity (Vmax), overall wall shear stress (WSS)] and segmental parameters [pulse wave velocity (PWV) and viscous energy loss (VEL)] were generated during postprocessing. The Student’s t-test or Mann-Whitney test was used to compare flow dynamics among the three groups.
Results
A total of 11 patients with TAAA (mean age 53.2±11.9 years; 10 males), 19 patients with AAA (mean age 58.0±11.7 years; 16 males), and 21 controls (mean age 55.4±15.0 years; 19 males) were analyzed. The patients with TAAA demonstrated a significantly higher RF and lower Vmax in the aortic arch compared to healthy controls. The whole length of the aorta in patients with TAAA was characterized by lower WSS, predominantly in the planes of pulmonary artery bifurcation and the middle infrarenal planes (all P values <0.001). As for segmental hemodynamics, compared to controls, patients with TAAA had a significantly higher PWV in the thoracic aorta (TAAA: median 11.41 m/s, IQR 9.56–14.32 m/s; control: median 7.21 m/s, IQR 5.57–7.79 m/s; P<0.001) as did those with AAA (AAA: median 8.75 m/s, IQR 7.35–10.75 m/s; control: median 7.21 m/s, IQR 5.57–7.79 m/s; P=0.024). Moreover, a greater VEL was observed in the whole aorta and abdominal aorta in patients with TAAA.
Conclusions
Patients with TAAA exhibited a stiffer aortic wall with a lower WSS and a greater VEL for the whole aorta, which was accompanied by a higher RF and lower peak velocity in the dilated portion of the aorta.
... 6 This could potentially lead to PVCs by increasing fibrous content as has been shown in chronic dilated aortas with increased WSS. 7 We conducted a prospective observational study with the aim of characterizing right ventricular outflow tract (RVOT) flow parameters, eccentricity and WSS with a 4D-flow MRI sequence. We correlated these markers with RVOT electrical amplitude abnormalities and PVC location, identified during 3D electroanatomical mapping ablation. ...
... 6 This local remodelling could potentially lead to PVCs by increasing myocardial fibrosis content, as has been shown in chronic dilated aortas with increased WSS. 7 RVOT PVC origin could be due to occult local remodelling that could be unmasked using advanced imaging technics and dense electrophysiological mapping. On the other hand, only 40% of our population developed PVCs on 'normal electrical tissue', representing what may be classified as the 'real' idiopathic PVC group. ...
... One is that low WSS causes endothelial cell dysfunction, affects the endothelial cell secretion mode, leads to increased production of vasoconstriction and in ammatory substances, decreases vasodilators and antioxidants, and increases the susceptibility of vessels to rupture [7]. The other is that high WSS often causes chronic damage to endothelial cells in vessel walls, resulting in decreased endothelial cells, increased permeability, elastic layer degeneration, and medial layer thinning of arterial vessel walls, which are also the main factors involved in aneurysm formation and growth [8][9]. In either case, when the pressure and shear stress of the vessel wall change in a non-physiological state, they will cause damage to endothelial cells of the vessel wall, resulting in blood stasis, arterial plaque formation, atherosclerosis, aneurysm formation, etc., affecting the blood ow volume and stability of the VA. ...
Background and purpose
Patients with craniocervical junction abnormalities (CJA) often exhibit vertebral artery (VA) abnormalities, and identifying these abnormalities can be beneficial for assessing patient symptoms and developing treatment plans.
Material and Methods
Sixty patients with CJA were admitted to our department from January 2018 to June 2022. Sixty healthy people were selected to undergo combined head and neck CTA, and the CTA images were imported into CFD-related software. The results were used to visualize and derive the lumen diameter (D), peak systolic velocity (PSV), mean blood flow velocity (MV), wall pressure (WP), wall shear stress (WSS) and other related data of vertebral arteries in different segments, and cross-sectional planes of the vertebral arteries at different segments were constructed to calculate the quantity of blood flow (Q) and the ratio of each index in each segment. The dizziness handicap inventory (DHI) was chosen to assess patient dizziness symptoms, and a multinomial logistic model was used to analyze the correlation between differences in vertebral artery hemodynamics due to patients with CJA and clinical symptoms such as dizziness.
Results
Compared with those in the control group, the mean DV3−V4, D\(\frac{\text{V}3-\text{V}4}{\text{V}1-\text{V}2}\)、QV3−V4、Q\(\frac{\text{V}3-\text{V}4}{\text{V}1-\text{V}2}\) of VA in the CJA group were significantly lower; the PSVV3−V4, PSV\(\frac{\text{V}3-\text{V}4}{\text{V}1-\text{V}2}\)、MVV1−V2、MVV3−V4、MV\(\frac{\text{V}3-\text{V}4}{\text{V}1-\text{V}2}\), WP and WSS in the CJA group were significantly greater; and the difference was statistically significant (P<0.05). According to the multinomial logistic regression analysis, for every 0.02 unit decrease in QV3−V4, the risk of increasing the DHI score to a higher grade increased by 40.49% compared with the original basis.
Conclusions
The V3-V4 segment of the vertebral artery in patients with CJA differs from that in the normal population in terms of hemodynamics, such as D, V, WP, and WSS, especially Q, and these differences lead to the occurrence of clinical symptoms such as dizziness and vertigo. The quantity of blood flow is negatively correlated with DHI, and age is positively correlated with DHI.
... Moreover, high WSS often leads to chronic damage to the endothelial cells of the vessel wall (15), thus causing a decrease in the endothelial cells of the arterial vessel wall, increased permeability of the vessel wall, degeneration of the elastic layer, and thinning of the middle layer, which are the main factors in Frontiers in Neurology 06 frontiersin.org the development and growth of aneurysms (16,17). This also provides a theoretical basis for the frequent coexistence of CJA with aneurysms in clinical practice. ...
Background and purpose
A three-dimensional reconstruction and data analysis of the vertebral artery (VA) with craniocervical junction abnormality (CJA) was performed by computational fluid dynamics (CFD) based on images to assess the impact of CJA on vertebral artery hemodynamics.
Methods
Retrospective analysis of combined head and neck computed tomography angiography (CTA) images of 60 patients with CJA and 60 normal patients admitted to our department from January 2018 to June 2022. The VA was reconstructed in three dimensions using CFD-related software, and the results were visualized to derive vertebral artery lumen diameter (D), peak systolic velocity (PSV), mean blood flow velocity (MV), wall pressure (P), wall shear stress (WSS), normalized WSS (NWSS), etc. Statistical analysis was used to analyze whether the data related to hemodynamics in the CJA group and the control group were statistically significant.
Results
The lumen diameter of the vertebral artery in the CJA group were less than the control group, and the difference was statistically significant (3.354 ± 0.562 vs. 3.744 ± 0.520, p < 0.05); the PSV, MV, P, WSS, and NWSS of the CJA group were increased compared with the control group, and the difference was statistically significant (1.235 ± 0.182 vs. 1.104 ± 0.145, 0.339 ± 0.063 vs. 0.307 ± 0.042, 24576.980 ± 7095.836 vs. 20824.281 ± 6718.438, 34.863 ± 6.816 vs. 31.080 ± 5.438, 0.272 ± 0.075 vs. 0.237 ± 0.067, p < 0.05).
Conclusion
In the complex CJA, the possibility of hemodynamic variation in the VAs is higher than in the normal population. The hemodynamic aspects of the vertebral artery in patients with CJA, such as diameter, flow velocity, flow, wall pressure and shear force, differ from those in the normal population and may lead to the occurrence of clinical symptoms, such as dizziness, so preoperative examinations such as combined head and neck CTA should be performed to clarify the vascular abnormalities.
... Dacron ® vascular graft, used to replace the aortic wall in AAR do not have biomechanical properties of the native vascular tissue [6][7][8][9][10]. Compliance (increase in volume for an increased in pressure) of a vascular prosthesis is 4-time lower than the aorta, and this mismatch between graft and aorta causes flow turbulence with serious clinical issues overtime. ...
Objective: aortic root enlargement (ARE) and descending thoracic aorta dilatation (DTAD) in combined aortic valve and ascending aorta replacement surgery (AV+AAR) are postoperative concerning issues. This retrospective observational analysis studies surgical factors which could determine those complications. Methods: 236 patients underwent AV+AAR. Mean-time follow-up by trans-thoracic echocardiography (TTE) and computer tomography (CT) was 44.7 ± 21.2 and 38.2 ± 18.4 months respectively. In long-term follow-up, outcome variables are: ARE equal/more than 10% of the preoperative TTE data and DTAD equal more than 5% of preoperative CT measurement at the same thoracic vertebrae axial slice. Results: ARE and DTAD appear strictly related to the discrepancy between prosthetic valve and straight vascular prosthesis diameters (p = 0.024), while there is not significant difference (log-rank = 0.917) related to aortic valve surgery type (replacement or repair). Considering diameter difference (DD) between vascular and aortic valve prosthesis, patients were subsequently grouped into two sections: L5 group, in which DD was less/equal than 5 mm, and M5, in which DD was more/equal than 5 mm. ARE was found in 30.8 % of L5 patients and only in 14.7 % among M5 patients (log-rank = 0.026). We have also observed descending thoracic aorta dilatation in 34.2 % of L5 and in 12.1 % of M5 (log-rank = 0.023). Conclusions: According with our data, difference between vascular prosthesis and aortic valve prosthesis equal/more than 5 mm is a protective factor against ARE and DATD.
... This is indicated in Table 1 where the OSI is significantly larger in the pre-operative case. Time durations with significant wall shear stress in combination with non-zero OSI have been suggested as a risk factor for cell-driven changes in the aortic wall structure [28], including development and progression of atherosclerosis [29,30]. ...
... This is more significant in the pre-operative case due to its stronger recirculation zone that is located towards the posterior side of the aortic valve. In the study by Kiema et al. (2022) [28], it was observed that in cases of a situation of non-zero OSI together with significant WSS, there is elevated risk for the incidence of aortic wall damage, including progression of atherosclerosis [29,30]. ...
Background:
This article presents the use of blood speckle Imaging (BSI) as an echocardiographic approach for the pre- and post-operative evaluation of subaortic membrane resection and aortic valve repair.
Method:
BSI, employing block-matching algorithms, provided detailed visualization of flow patterns and quantification of parameters from ultrasound data. The 9-year-old patient underwent subaortic membrane resection and peeling extensions of the membrane from under the ventricular-facing surface of all three aortic valve leaflets.
Result:
Post-operatively, BSI demonstrated improvements in hemodynamic patterns, where quantified changes in flow velocities showed no signs of stenosis and trivial regurgitation. The asymmetric jet with a shear layer and flow reversal on the posterior aspect of the aorta was corrected resulting in reduced wall shear stress on the anterior aspect and reduced oscillatory shear index, which is considered a contributing element in cellular alterations in the structure of the aortic wall.
Conclusion:
This proof-of-concept study demonstrates the potential of BSI as an emerging echocardiographic approach for evaluating subaortic and aortic valvar repair. BSI enhances the quantitative evaluation of the left ventricular outflow tract of immediate surgical outcomes beyond traditional echocardiographic parameters and aids in post-operative decision-making. However, larger studies are needed to validate these findings and establish standardized protocols for clinical implementation.
... These proliferative VSMCs are also abnormal, since they have been shown to express both contractile and synthetic protein markers, and are more susceptible to apoptosis as well, eventually causing thinning of the tunica media [31]. It thus seems that progressive weakening of the medial layer, which can sometimes be attributed to an alteration in flow and hemodynamic conditions, as is the case with splenic artery aneurysms for example [29,37], is central to the development of both aortic aneurysms and VAAs [38]. ...
Aortic and visceral aneurysms affect large arterial vessels, including the thoracic and abdominal aorta, as well as visceral arterial branches, such as the splenic, hepatic, and mesenteric arteries, respectively. Although these clinical entities have not been equally researched, it seems that they might share certain common pathophysiological changes and molecular mechanisms. The yet limited published data, with regard to newly designed, novel therapies, could serve as a nidus for the evaluation and potential implementation of such treatments in large artery aneurysms. In both animal models and clinical trials, various novel treatments have been employed in an attempt to not only reduce the complications of the already implemented modalities, through manufacturing of more durable materials, but also to regenerate or replace affected tissues themselves. Cellular populations like stem and differentiated vascular cell types, large diameter tissue-engineered vascular grafts (TEVGs), and various molecules and biological factors that might target aspects of the pathophysiological process, including cell-adhesion stabilizers, metalloproteinase inhibitors, and miRNAs, could potentially contribute significantly to the treatment of these types of aneurysms. In this narrative review, we sought to collect and present relevant evidence in the literature, in an effort to unveil promising biological therapies, possibly applicable to the treatment of aortic aneurysms, both thoracic and abdominal, as well as visceral aneurysms.
... 37 Further, Bollache and colleagues found that increased regional WSS is associated with decreased elastic fiber thickness, and Kiema and colleagues showed that WSS correlates with aortic media degeneration and aortic wall thickness. 38,39 These findings support the relationship between abnormal valve-mediated flow hemodynamics, as determined by 4D flow MRI , with biomechanical changes in the aortic wall and their implication in BAV aortopathy. Furthermore, they provided evidence that WSS is a key driver of aortic dilation and a promising risk measure. ...
Four-dimensional flow MRI is a powerful phase contrast technique used for assessing three-dimensional (3D) blood flow dynamics. By acquiring a time-resolved velocity field, it enables flexible retrospective analysis of blood flow that can include qualitative 3D visualization of complex flow patterns, comprehensive assessment of multiple vessels, reliable placement of analysis planes, and calculation of advanced hemodynamic parameters. This technique provides several advantages over routine two-dimensional flow imaging techniques, allowing it to become part of clinical practice at major academic medical centers. In this review, we present the current state-of-the-art cardiovascular, neurovascular, and abdominal applications.
... Aortic wall alterations are indeed at least partly related to the flow constraints applied (Bollache et al., 2018). The use of wall shear stress measurement, as shown in 4D flow MRI (Guala et al., 2022;Kiema et al., 2022;Soulat et al., 2022;Qin et al., 2023), is thus particularly useful, although yet to be available with echocardiography. An appealing prospect is the use of ultrasound innovations in the field flow mapping to combine aortic wall markers, such as stiffness, and wall shear stress, to appreciate better the causative phenomena of aortic remodeling and aneurysmal progression (Cai et al., 2019;Kainuma et al., 2022). ...
Purpose: Aortic maximal rate of systolic distention (MRSD) is a prognosis factor of ascending aorta dilatation with magnetic resonance imaging. Its calculation requires precise continuous tracking of the aortic diameter over the cardiac cycle, which is not feasible by focused ultrasound. We aimed to develop an automatic aortic acquisition using ultrafast ultrasound imaging (UUI) to provide access to the aortic MRSD. Methods: A phased array probe and developed sequences at 2000 frames/s were used. A created interface automatically tracked the anterior and posterior aortic walls over the cardiac cycle. Tissue Doppler allowed a precise estimation of the walls’ movements. MRSD was the maximum derivative of the aortic diameter curve over time. To assess its feasibility, 34 patients with bicuspid aortic valve (BAV) and 31 controls were consecutively included to evaluate the BAV-associated aortopathy at the sinus of Valsalva, the tubular ascending aorta, and the aortic arch. Results: UUI acquisitions and the dedicated interface allow tracking of the aortic diameter and calculating the MRSD for the BAV patients and controls (mean age of 34 vs. 43 years, p = 0.120). A trend toward lower deformation in the different aortic segments was observed, as expected. Still, only the MRSD with UUI was significantly different at the sinus of Valsalva in this small series: (0.61 .103.s–1 [0.37–0.72] for BAV patients vs. 0.92 .103.s–1 [0.72–1.02] for controls, p = 0.025). Conclusion: Aortic deformation evaluated with UUI deserves attention with a simple and automated measurement technique that could assess the segmental aortic injury associated with BAV.
