Aortic Arch Geometry Research Articles

Deep learning based assessment of hemodynamics in the coarctation of the aorta: comparison of bidirectional recurrent and convolutional neural networks.

The utilization of numerical methods, such as computational fluid dynamics (CFD), has been widely established for modeling patient-specific hemodynamics based on medical imaging data. Hemodynamics assessment plays a crucial role in treatment decisions for the coarctation of the aorta (CoA), a congenital heart disease, with the pressure drop (PD) being a crucial biomarker for CoA treatment decisions. However, implementing CFD methods in the clinical environment remains challenging due to their computational cost and the requirement for expert knowledge. This study proposes a deep learning approach to mitigate the computational need and produce fast results. Building upon a previous proof-of-concept study, we compared the effects of two different artificial neural network (ANN) architectures trained on data with different dimensionalities, both capable of predicting hemodynamic parameters in CoA patients: a one-dimensional bidirectional recurrent neural network (1D BRNN) and a three-dimensional convolutional neural network (3D CNN). The performance was evaluated by median point-wise root mean square error (RMSE) for pressures along the centerline in 18 test cases, which were not included in a training cohort. We found that the 3D CNN (median RMSE of 3.23mmHg) outperforms the 1D BRNN (median RMSE of 4.25mmHg). In contrast, the 1D BRNN is more precise in PD prediction, with a lower standard deviation of the error (±7.03mmHg) compared to the 3D CNN (±8.91mmHg). The differences between both ANNs are not statistically significant, suggesting that compressing the 3D aorta hemodynamics into a 1D centerline representation does not result in the loss of valuable information when training ANN models. Additionally, we evaluated the utility of the synthetic geometries of the aortas with CoA generated by using a statistical shape model (SSM), as well as the impact of aortic arch geometry (gothic arch shape) on the model's training. The results show that incorporating a synthetic cohort obtained through the SSM of the clinical cohort does not significantly increase the model's accuracy, indicating that the synthetic cohort generation might be oversimplified. Furthermore, our study reveals that selecting training cases based on aortic arch shape (gothic versus non-gothic) does not improve ANN performance for test cases sharing the same shape.

Bronchus compression is a predictor for reobstruction in coarctation with hypoplastic arch repair.

The surgical treatment of coarctation of aorta with hypoplastic aortic arch (CoA/HAA) was challenging to achieve long-lasting arch patency. We reviewed early and late outcomes in our centre and identified predictors for arch reobstruction. A retrospective analysis of medical records was performed to identify CoA/HAA patients who underwent primary arch reconstruction via median sternotomy between 2011 and 2020. Preoperative aortic arch geometry was analysed with cardiac computed tomographic angiography. Bedside flexible fibre-optic bronchoscopy was routinely performed after surgery in intensive care unit. There were 104 consecutive patients (median age 39.5 days) who underwent extended end-to-end anastomosis, extended end-to-side anastomosis and autograft patch augmentation. Early mortality was 3.8% and overall survival was 94.1% [95% confidence interval (CI) 89.6-98.8%] at 1, 3 and 5 years. Reobstruction-free survival was 85.1% (95% CI 78.4-92.3%) at 1 year, 80.6% (95% CI 73.1-88.9%) at 3 years and 77.4% (95% CI 69.2-86.6%) at 5 years. Preoperative aortic arch geometric parameters were not important factors for reobstruction. Nineteen patients (18.3%) were detected with left main bronchus compression (LMBC) on flexible fibre-optic bronchoscopy. Cardiopulmonary bypass time [P < 0.001, hazard ratio (95% CI): 1.02 (1.01-1.03)] and postoperative LMBC [P = 0.034, hazard ratio (95% CI): 2.99 (1.09-8.23)] were independent predictive factors on multivariable Cox regression analysis of reobstruction-free survival. Aortic arch can be satisfactorily repaired by extended end-to-end anastomosis, extended end-to-side anastomosis and autograft patch augmentation via median sternotomy in CoA/HAA. Cardiopulmonary bypass time and postoperative LMBC detected by flexible fibre-optic bronchoscopy are significant predictors for long-term arch reobstruction.

Does Aortic Arch Anatomy Affect Stroke Laterality in Transcatheter Aortic Valve Implantation?

Background. Current data reveal a predominace of left as opposed to right-sided cerebral strokes after transcatether aortic valve replacement (TAVR). Aortic arch variations might raise the likelihood of cardioembolic particles entering predominantly the left cerebral circulation during catheter tracking and manipulation. Aim. We sought to analyse the impact of aortic arch anatomy on stroke laterality (right vs. left) in patients undergoing TAVR. Methods. All patients who developed a symptomatic, periprocedural left- or right-sided ischemic stroke after TAVR between June 2007 and August 2022 were included in this study. Multislice computed tomography (MSCT) analysis was used to assess aortic arch anatomy, arch configuration (types I–III), arch tortuosity, and the determination of the take-off angles of the supraaortic arteries. Results. The final study cohort comprised 77 patients. Periprocedural ischemic stroke was left-sided in 66.2% of the patients (n = 51) and right-sided in 33.8% (n = 26) (p = 0.006). MSCT analysis revealed a standard aortic arch branching pattern in 70.1% (n = 54) and a common origin of the brachiocephalic and left common arteries (bovine arch anatomy) in 29.9% (n = 23) of the patients. There was no association between the anatomical variations of the aortic arch and stroke laterality p = 0.601 . Frequency of arch configuration types was 15.6% (type I), 74.0% (type II), and 10.4% (type III). There was no correlation between the different types of configuration and the laterality of periprocedural stroke (type I: p = 0.526 , type II: p = 0.585 , and type III: p = 1.000 ). Aortic arch tortuosity and angulation of the supraaortic arteries did also not differ between right- and left-sided strokes. Conclusion. Our data add evidence that there is a significant propensity for left-hemispheric strokes in patients undergoing TAVR. However, MSCT analysis in our cohort did not reveal an association between aortic arch geometry and laterality of stroke.

Influence of Bovine Arch Anatomy on Surgical Outcomes of Coarctation of the Aorta.

This study aimed to evaluate the outcome of coarctation of the aorta (CoA) repair with a special interest in bovine arch anatomy. Fifty-six patients who underwent CoA repair between 2010 and 2021 were included in this retrospective study. Of these, 11 patients had bovine arch anatomy. Surgical outcomes were reviewed. Computed tomography was used to analyze aortic arch geometry for all cases preoperatively. The gap between anastomotic sites was calculated at the linear region of the lesser curvature of the aortic arch between the distal ascending aorta and the proximal descending aorta. CoA repair was performed at a median age of 39days (median body weight 3.3kg). Thirty-two patients underwent extended direct anastomosis, 22 patients underwent direct anastomosis, and two patients underwent lesser curvature patch augmentation. The median follow-up period was 47months. There were no early deaths. In patients who underwent direct and extended direct anastomosis, nine recoarctation and one left pulmonary venous obstruction events occurred. Moreover, freedom from these adverse events was 81% in normal arch and 50% in bovine arch patients at 10years (P = 0.04). Two patients with a bovine arch anatomy who underwent lesser curvature patch augmentation had good outcomes. The distal arch was narrower and longer, and the gap between anastomotic sites was longer in patients with a bovine arch anatomy than with a normal arch (P < 0.01). In CoA with a bovine arch anatomy, the gap between anastomotic sites was long. This adversely influenced the outcomes of the CoA repairs.

In Vivo Quantification of Cardiac-Pulsatility-Induced Motion Before and After Double-Branched Endovascular Aortic Arch Repair

The Relay®Branch stent-graft (Terumo Aortic, Sunrise, FL, USA) offers a custom-made endovascular solution for complex aortic arch pathologies. In this technical note, a modified electrocardiography (ECG)-gated computed tomography (CT)-based algorithm was applied to quantify cardiac-pulsatility-induced changes of the aortic arch geometry and motion before and after double-branched endovascular repair (bTEVAR) of an aortic arch aneurysm. This software algorithm has the potential to provide novel and clinically relevant insights in the influence of bTEVAR on aortic anatomy, arterial compliance, and stent-graft dynamics.

Vortex dynamics of veno-arterial extracorporeal circulation: A computational fluid dynamics study

Veno-arterial extra corporeal membrane oxygenation (VA-ECMO) is a modified heart lung machine used for patients with both heart and lung failure. This results in retrograde supply of oxygenated blood through the femoral artery in which the unsteady pulsating antegrade flow from the aorta interacts with a steady, uniform, and retrograde flow from the femoral artery, creating a mixing zone. This work aims to provide a mechanistic interpretation of VA-ECMO by developing an in-silico framework using computational fluid dynamics. We performed several numerical simulations to investigate the effects of aortic geometry on VA-ECMO by implementing two idealized full aorta models and studied the formation of secondary flow features and vortices. We used vortex identification methods to capture the three-dimensional vortical structures formed under various ECMO support levels. Our results show that under pulsatile aortic flow and 80% of ECMO support, the streamwise vorticity and aortic arch geometry strongly influence the mixing zone. Furthermore, we found that pulsatility at the aortic inlet causes oscillation in secondary flow structures at the abdominal aorta leading to unsteadiness in ECMO flow and differential wall shear stress. We also examined the effects of VA-ECMO flow rates on secondary flow and vortical structures. We show that the location and complexity of secondary flows and vortical structures are affected by ECMO support levels and geometry of aortic segments. Together, we believe that this computational framework is a crucial step in understanding flow features and vortical structures formed during VA-ECMO administration, which can improve patient care and ECMO management.

Altered hemodynamics by 4D flow cardiovascular magnetic resonance predict exercise intolerance in repaired coarctation of the aorta: an in vitro study

BackgroundCoarctation of the aorta (CoA) is associated with decreased exercise capacity despite successful repair. Altered flow patterns have been identified due to abnormal aortic arch geometry. Our previous work demonstrated aorta size mismatch to be associated with exercise intolerance in this population. In this study, we studied aortic flow patterns during simulations of exercise in repaired CoA using 4D flow cardiovascular magnetic resonance (CMR) using aortic replicas connected to an in vitro flow pump and correlated findings with exercise stress test results to identify biomarkers of exercise intolerance.MethodsPatients with CoA repair were retrospectively analyzed after CMR and exercise stress test. Each aorta was manually segmented and 3D printed. Pressure gradient measurements from ascending aorta (AAo) to descending aorta (DAo) and 4D flow CMR were performed during simulations of rest and exercise using a mock circulatory flow loop. Changes in wall shear stress (WSS) and secondary flow formation (vorticity and helicity) from rest to exercise were quantified, as well as estimated DAo Reynolds number. Parameters were correlated with percent predicted peak oxygen consumption (VO2max) and aorta size mismatch (DAAo/DDAo).ResultsFifteen patients were identified (VO2max 47 to 126% predicted). Pressure gradient did not correlate with VO2max at rest or exercise. VO2max correlated positively with the change in peak vorticity (R = 0.55, p = 0.03), peak helicity (R = 0.54, p = 0.04), peak WSS in the AAo (R = 0.68, p = 0.005) and negatively with peak WSS in the DAo (R = − 0.57, p = 0.03) from rest to exercise. DAAo/DDAo correlated strongly with change in vorticity (R = − 0.38, p = 0.01), helicity (R = − 0.66, p = 0.007), and WSS in the AAo (R = − 0.73, p = 0.002) and DAo (R = 0.58, p = 0.02). Estimated DAo Reynolds number negatively correlated with VO2max for exercise (R = − 0.59, p = 0.02), but not rest (R = − 0.28, p = 0.31). Visualization of streamline patterns demonstrated more secondary flow formation in aortic arches with better exercise capacity, larger DAo, and lower Reynolds number.ConclusionsThere are important associations between secondary flow characteristics and exercise capacity in repaired CoA that are not captured by traditional pressure gradient, likely due to increased turbulence and inefficient flow. These 4D flow CMR parameters are a target of investigation to identify optimal aortic arch geometry and improve long term clinical outcomes after CoA repair.

The Impact of a Bicuspid Aortic Valve on Aortic Geometry and Function in Patients with Aortic Coarctation: A Comprehensive CMR Study

Background: An isolated bicuspid aortic valve (BAV) is associated with structural and functional abnormalities of the aorta and the left ventricle (LV). Although ~50% of patients with aortic coarctation (CoA) have a BAV, less is known about its impact on LV function and aortic geometry and function in CoA patients. In this cardiovascular magnetic resonance imaging (CMR) study, we analysed markers of LV and aortic function as well as aortic geometry in a large cohort of CoA patients with a BAV and compared them with CoA patients with a tricuspid aortic valve (TAV). Methods: We included 48 patients with a BAV (18.4 ± 9.3 years) and 45 patients with TAV (20.7 ± 9.9 years). LV volumes, mass and ejection fraction as well as aortic distensibilty, pulse wave velocity (PWV) were measured from standard cine CMR and phase-contrast CMR images. 2-dimensional CMR feature tracking (2DCMR-FT) was performed to measure longitudinal, circumferential and radial strain and strain rate of the LV. Aortic arch geometry was classified as romanic, gothic and crenel. Results: LV volumes, mass and ejection fraction as well as aortic distensibility and PWV did not significantly differ between the BAV and the TAV group. There was also no significant difference for LV global longitudinal, radial and circumferential strain and strain rate between both groups. Patients with a BAV had more commonly a gothic aortic arch compared to TAV patients, but this difference was not statistically significant (22 vs. 14, p = 0.2). Ascending and descending aortic distensibility correlated with LV mass in the entire patient group (p < 0.001). Global longitudinal, circumferential and radial strain (GLS, GCS, GRS) and global longitudinal and circumferential strain rate (GLSR, GCSR) correlated with LV ejection fraction (p < 0.001). Conclusion: Our data suggest that the presence of a BAV does not adversely impact LV and aortic function in children and young adults with CoA. The correlation of global circumferential, longitudinal and radial strain values with LV ejection fraction demonstrates that 2D-CMR-FT might provide additional information related to ventricular function in CoA patients.

Changes in aortic arch geometry and the risk for Stanford B dissection.

BackgroundThe increase in aortic diameter is not closely associated with type B aortic dissection (TBAD); morphological risk factors other than aortic diameter may help to better identify patients at risk for TBAD. The purpose of this study was to investigate possible morphological factors associated with the occurrence of TBAD.MethodsThis study was a retrospective, multicenter, cross-sectional study. We collected 94 patients with TBAD as the TBAD group and 534 patients with healthy aortas as the healthy control group. Morphometric data were collected on three-dimensional models of the thoracic aorta. A propensity score matching (PSM) analysis was conducted to reduce the potential for confounding by baseline factors.ResultsThe number of patients in the TBAD group was 75 after PSM. Longer lengths of the aortic arch (28.00±7.42 vs. 25.14±7.11 cm) were observed in patients with TBAD. The width (80.04±17.27 vs. 71.73±15.55 mm) and height (24.92±11.39 vs. 19.37±10.10 mm) of the aortic arch in patients with TBAD were both larger than those of healthy controls. The morphological changes associated with the occurrence of type B acute dissection were most pronounced in the geometry of the aortic arch.ConclusionsThis study demonstrates that TBAD was associated with longer lengths of aortic arch and with larger arch height and width.

Selective Lesser Curvature Augmentation With Geometric Study for Repair of Aortic Arch Obstruction

We repaired aortic coarctation and interrupted aortic arch with extended end-to-end anastomosis (EAA) through median sternotomy and performed lesser curvature augmentation with a pulmonary autograft patch (PAP) in selected patients with a long gap between anastomotic sites. We reviewed these outcomes and geometric implications. All neonates and infants with biventricular morphology who underwent aortic arch reconstruction through median sternotomy between 2005 and 2019 were evaluated. Aortic arch geometry was analyzed with computed tomography routinely performed before and after surgery from 2009 on. There were 91 consecutive patients (median age, 1.2 months). Ten patients received PAP. One early death and no late deaths were noted. Overall survival was 98.9% at 10 years. Two left bronchomalacia and 1 recoarctation occurred in patients with EAA. Freedom from recoarctation was 97.4% at 10 years. We examined 68 patients with computed tomography. We used PAP in patients with a significantly longer gap between anastomotic sites indexed by the square root of the body surface area; its cutoff value was 29.0 mm/m (area under the curve, 0.86 mm/m). The PAP created a significantly greater arch angle (median, 91° versus 83°) and arch/descending diameter ratio (median, 1.2 versus 1.0) and preserved the arch width indexed by the square root of the body surface area (median, before surgery: 35.7 versus 34.4 mm/m; after surgery: 36.5 versus 29.9mm/m), compared withEAA. Aortic arch reconstruction with the current combined strategy provides satisfactory outcomes. Guided by geometric analysis, lesser curvature augmentation can be applied to patients who might experience recoarctation or airway compression with a directly anastomosed aortic arch.

Aorta size mismatch predicts decreased exercise capacity in patients with successfully repaired coarctation of the aorta

ObjectiveCoarctation of the aorta (CoA) is associated with decreased exercise capacity despite successful repair with no residual stenosis; however, the hemodynamic mechanism remains unknown. This study aims to correlate aortic arch geometry with exercise capacity in patients with successfully repaired CoA and explain hemodynamic changes using 3-dimensional–printed aorta models in a mock circulatory flow loop. MethodsA retrospective chart review identified patients with CoA repair who had cardiac magnetic resonance imaging and an exercise stress test. Measurements included aorta diameters, arch height to diameter ratio, left ventricular function, and percent descending aorta (%DAo) flow. Each aorta was printed 3-dimensionally for the flow loop. Flow and pressure were measured at the ascending aorta (AAo) and DAo during simulated rest and exercise. Measurements were correlated with percent predicted peak oxygen consumption (VO2 max). ResultsFifteen patients (mean age 26.8 ± 8.6 years) had a VO2 max between 47% and 126% predicted (mean 92 ± 20%) with normal left ventricular function. DAo diameter and %DAo flow positively correlated with VO2 (P = .007 and P = .04, respectively). AAo to DAo diameter ratio (DAAo/DDAo) negatively correlated with VO2 (P < .001). From flow loop simulations, the ratio of %DAo flow in exercise to rest negatively correlated with VO2 (P = .02) and positively correlated with DAAo/DDAo (P < .01). ConclusionsThis study suggests aorta size mismatch (DAAo/DDAo) is a novel, clinically important measurement predicting exercise capacity in patients with successful CoA repair, likely due to increased resistance and altered flow distribution. Aorta size mismatch and %DAo flow are targets for further clinical evaluation in repaired CoA.

Association between aortic arch angulation and bird-beak configuration after thoracic aortic stent graft repair of type B aortic dissection.

The goal of this study was to investigate factors favouring the bird-beak configuration after thoracic endovascular aortic repair (TEVAR) for type B aortic dissection. We retrospectively analysed 76 patients with type B aortic dissection who underwent landing zone 1 and 2 TEVAR from December 2015 to January 2018. Preoperative aortic arch geometry (aortic arch length, maximal diameter and angulation), stent graft details and operative details were evaluated. A bird-beak configuration was defined as a ≥5-mm gap between the proximal end of the stent and the aortic wall of the lesser curvature. Patients were stratified into those with (n = 46) and without (n = 30) a bird-beak configuration. The baseline demographics, dissection chronicity, clinical features and implanted devices were largely similar between the 2 groups. No significant difference was observed in the arch length or maximal arch diameter. However, the mean aortic arch angulation was greater in patients with than without a bird-beak configuration (61.4° vs 51.3°; P < 0.001). No influence of either the stent graft brand or the proximal stent graft type was observed. The multivariable analysis showed that the aortic arch angulation was an independent risk factor for a bird-beak configuration (odds ratio 1.15, 95% confidence interval 1.07-1.24; P < 0.001). A cut-off angle of 59.15° was predictive of a bird-beak configuration (sensitivity 59%; specificity 77%). The preoperative aortic arch angulation was an independent predictor of a postoperative bird-beak configuration in patients with type B aortic dissection who underwent TEVAR that involved the aortic arch. An angle of >59.15° may imply a relatively hostile anatomy with a higher risk of a bird-beak configuration.

Aortic arch geometry predicts outcome in patients with Loeys-Dietz syndrome independent of the causative gene.

This study aimed to investigate the potential association between imaging features and cardiovascular outcomes in patients with Loeys–Dietz syndrome (LDS). We performed a retrospective cohort study of 36 patients with LDS and described cardiovascular events and imaging data. We observed different clinical courses in patients with LDS, irrespective of the causative gene. Angular or elongated aortic arch geometry correlated with aortic dissection (R = .39, p = .02), occurrence of the first cardiovascular event before 45 years of age (R = .36, p = .03), and the number of operations (R = 0.47, p = .004), but not with age (R = −.05, p = .79) or the causative gene (R = −0.04, p = .79). Relative absences of cardiovascular events at ages 20, 40, and 60 were 100, 75, and 56%, respectively, in patients with “romanesque” aortic arches, and 74, 39, and 21%, respectively, in patients with “gothic” and “elongated” aortic arches (p = .03). Angular or elongated aortic arch geometry is associated with early‐onset of disease and a worse cardiovascular outcome in LDS patients. Large multicenter studies are warranted to elucidate the impact of aortic arch morphology evaluation in clinical practice.

Altered aortic arch geometry in patients with type B aortic dissection.

This study aims to evaluate differences in proximal aorta geometry and identify specific anatomical predictors of type B aortic dissection (TBAD). We evaluated computed tomographic angiograms of controls (n = 185) and patients with acute TBAD (n = 173). Using propensity score matching, we created 2 groups of 127 patients. 3mensio Vascular software was used to analyse the computed tomographic angiograms and measure the diameter, length, tortuosity index and angulation of the proximal aorta (divided into ascending aorta and aortic arch). Tortuosity index was calculated by dividing the centre lumen line length of the aortic segment by its shortest length. Angulation was measured by the centre lumen line 'tangent line angle'. Two independent multivariable models identified significant anatomical associations regarding the tortuosity and angulation geometry. Aortic diameter and ascending aorta and aortic arch lengths in TBAD increased significantly. The aortic arch tortuosity was significantly higher in the TBAD group (P < 0.001), with no difference regarding the ascending aorta (P = 0.11). Ascending aorta and aortic arch angulation were significantly higher in the TBAD group (P = 0.01, P < 0.001, respectively). Multivariable analyses showed that increased aortic arch tortuosity and angulation were significant predictors of the development of TBAD [odds ratio (OR) 1.91, 95% confidence interval (CI) 1.40-2.59; P < 0.001 and OR 1.08, 95% CI 1.04-1.12; P < 0.001], respectively. In addition to proximal aorta dilation and elongation, we identified increased aortic arch tortuosity and angulation as possible specific predictors of TBAD.

Haemodynamics of Different Configurations of a Left Subclavian Artery Stent Graft for Thoracic Endovascular Aortic Repair

Branched stent grafts represent a viable option for left subclavian artery (LSA) revascularisation in patients treated by thoracic endovascular aortic repair (TEVAR) for Zone 2 lesions. This study investigated the haemodynamic performance of different LSA branched stent graft configurations as potential determinants of thrombotic and stroke risks. A three dimensional aortic arch geometry extracted from post-operative computed tomography images of a TEVAR patient using a single LSA branched aortic endograft was modified in silico to obtain ten potential LSA branched stent graft configurations: five down facing (0-5 - 10mm aortic protrusion with 10-12mm internal diameter), four curved (30-60° with antegrade/retrograde orientation), and one LSA orifice misalignment. The 0mm down facing stent graft was considered base configuration. Computational fluid dynamic analyses were performed to identify differences in pressure, energy, and wall shear stress (WSS) based parameters. Total pressure drop and energy loss variations among configurations were not greater than 5mmHg (6% of mean arterial pressure) and 5.7mW (0.7% of cardiac power), respectively. Protrusions up to 5mm created clinically insignificant flow disturbances. However, stent graft protrusions further into the aortic lumen created more complex haemodynamics, characterised by larger energy loss and more prominent flow recirculation. Protrusion greater than 5mm into the lumen was associated with larger areas of elevated maximum WSS (>20Pa) along the outer surface of the branched stent graft. Arterial haemodynamic characteristics are affected by LSA branched stent graft configurations, with pressure drops and energy losses likely to be clinically insignificant. The length of the stent graft protrusion into the aortic lumen generated the largest haemodynamic variations in the aortic system. Protrusions up to 5mm have smaller risk of potential thrombus generation. Conversely, larger protrusions into the aortic lumen showed more disturbed haemodynamics, suggesting a greater risk of potential thrombus formation, which may be clinically important over time.

Aortic Coarctation a Systemic Vessel Disease-Insights from Magnetic Resonance Imaging.

Even after successful aortic coarctation (CoA) repair, hypertension causes premature morbidity and mortality. The mechanisms are not clear. The aim was to evaluate elastic wall properties and aortic morphology and to correlate these results with severity of restenosis, hypertension, aortic arch geometry, noninvasive pressure gradients, and time and kind of surgical procedure. Eighty-nine patients (17 ± 6.3 years) and 20 controls (18 ± 4.9 years) were examined using magnetic resonance imaging (MRI). In addition to contrast-enhanced MR angiography and flow measurements, CINE MRI was performed to assess the relative change of aortic cross-sectional areas at diaphragm level to calculate aortic compliance (C). Fifty-four percent of all patients showed hypertension (> 95th percentile), but more than half of them had no significant stenosis (defined as ≥30%). C was lower in CoA than in controls (3.30 ± 2.43 vs. 4.67 ± 2.21 [10-5 Pa-1 m-2]; p = 0.024). Significant differences in compliance were found between hyper- and normotensive patients (2.61 ± 1.60 vs. 4.11 ± 2.95; p = 0.01), and gothic and Romanesque arch geometry (2.64 ± 1.58 vs. 3.78 ± 2.81; p = 0.027). There was a good correlation between C and hypertension (r = 0.671; p < 0.01), but no correlation between C (and hypertension) and time or kind of repair, restenosis, or pressure gradients. The decreased compliance, a high rate of hypertension without restenosis, and independency of time and kind of repair confirm the hypothesis that CoA may not be limited to isthmus region but rather be a widespread (systemic) vascular anomaly at least in some of the CoA patients. Therefore, aortic compliance should be assessed in these patients to individually tailor treatment of CoA patients with restenosis and/or hypertension.

Three dimensional numerical analysis of hemodynamic of stenosed artery considering realistic outlet boundary conditions

Background and objectiveMortality rate increases globally among which one third is due to diseased blood vessels. Due to late diagnoses of the disease in vessels (severe stenoses), qualitative and rapid assessment becomes difficult. Earlier assessment of stenoses can lead to formulation of effective treatment protocol. It is often found that proliferation of secondary stenoses at downstream of a stenosed vessel depends on the degree of severity of primary stenoses. Numerical investigation of flow dynamics of blood in such condition helps in prediction of distributed field of secondarystenoses. This investigation also requires consideration of rigorous boundary conditions at inlet and outlet of defined flow domain. MethodsPatient-specific geometry of aortic arch with stenoses in descending aorta was considered for numerical estimation of biofluid dynamics. Boundary conditionsat inlet and outlet were extracted from time-resolved pulsed Doppler Ultrasound imaging at appropriate sections of the vessel. Womersley inlet flux was considered. Flow parameters like wall shear stress, oscillatory shear index, etc. were evaluated at upper and lower aortic arch of the vessel at different combinations of boundary conditions at inlet and four outlets respectively. ResultsEffect of outlet boundary conditions were acknowledged for the progression of secondary stenoses. Severity of primary stenoses was found influencing the progression of secondary stenoses. It was found that the outlets Left Subclavian Artery and Left Common Carotid Artery greatly influence the flow dynamic structure within the stenosed aortic arch. Simultaneously, lower wall of aortic-arch had shown more affinity for secondary stenoses progression. ConclusionAortic arch is a vital anatomical region of circulatory system which is vulnerable to progression of secondary stenoses in presence of primary stenoses in ascending or descending aorta. It also drives the author to speculate the influence of anurysm in descending aorta on this landmark of aortic arch.

Comparison of hemodynamics in post-operation coarctation of aorta patients with different aortic arch geometry

Comparison of hemodynamics in post-operation coarctation of aorta patients with different aortic arch geometry

The Degree of Question Mark of Aorta Can Predict the Thrombosis Rate in the False Lumen of a Type-B Aortic Dissection After TEVAR

Objective：Thoracic endovascular aortic repair (TEVAR) of type B aortic dissection (AD) is to initiate the thrombosis in the false lumen to eventually result in aortic remodeling. We aim to find out whether the false lumen (FL) thrombosis rate after TEVAR can be predicted accurately by an index that expresses the degree of aortic arch angulation. Method: Three-dimensional aortic arch geometry of 39 type B AD patients (mean age: 48years) after TEVR were reconstructed from post-operative CT images. For the first time, the question mark which take into account the curvature of both aortic arch and the descending aorta was introduced to indicate the aortic arch morphology. The degree of question mark and the angles of aortic arch defined by previous literatures were measured. Moreover, hemodynamics for ADs with different question mark degree were numerically computed using different models. Result: No correlation between the aortic arch angles defined by previous researchers and the rate of thrombosis. However, the degree of question mark has negatively correlation with FL thrombosis (r=-.7394; p<.001). In addition, regions of recirculating flow and low wall shear stress (WSS) in the FLs decreased with the increase of the degree of question mark of the aorta. Conclusion: The degree of question mark proposed in this paper is a good description of the aortic arch geometry after TEVAR in patients with aortic B-type dissection. It is negatively correlated with postoperative FL thrombosis, the higher the question mark degree was, the less likely it was to form a complete thrombus.

Arterial hypertension in children after aortic coarctation repair: current challenges for diagnostics and treatment

Coarctation of the aorta is a well-studied congenital heart disease. Our understanding of this congenital heart disease evolves every year from simple obstructive aortic lesions to systemic dysfunction of the cardiovascular system. In the past two decades, there has been a progressive decrease in mortality and early postoperative complications of newborns and infants with aortic coarctation. However, these patients with coarctation of aorta have a high risk of postoperative complications in the long-term period, despite successful correction at an early age. This review will focus on the issues mainly related to blood pressure. Arterial hypertension has been reported to occur in up to 90% of patients, and is considered as the main cause of premature cardiovascular diseases. The development of arterial hypertension in patients after correction of aortic coarctation is likely to be multifactorial and may be associated with the changes in elastic properties of the aorta wall, presence of residual obstruction, changes in the aortic arch geometry, immune-inflammatory disorders and changes in the regulation of renin-angiotensin and baroreceptors. Also described are the prevalence and pathophysiology of arterial hypertension in children who have undergone aortic coarctation repair. Due attention is given to the issues of accurate blood pressure measurement at an early stage of arterial hypertension. Although the patterns for diagnostics of arterial hypertension in adults are well established, we highlight the issues of premature cardiovascular events development in children and describe the techniques, which help provide complementary information for cardiovascular assessment in this group of patients. Received 7 August 2018. Revised 6 December 2018. Accepted 10 December 2018. AcknowledgmentWe would like to express our gratitude to Sergey M. Ivantsov for technical support. Funding: The study did not have sponsorship. Conflict of interest: Authors declare no conflict of interest.