Aortic elongation part I: the normal aortic ageing process

The preferable position for quantifying left ventricular diameter by transthoracic echocardiography

BACKGROUND

In quantifying left ventricular (LV) diameter, which position for echocardiographic measurements, mitral valve tip level (MV-tip) or LV mid level (LV-mid), more accurately represents the LV volume is unclear. Furthermore, which factor affects the measurement error also has not been elucidated.

METHODS

We enrolled 150 patients without myocardial infarction and local asynergy who underwent echocardiography and cardiac magnetic resonance imaging (CMRI). Echocardiographic LV diastolic diameter (LVDD) and LV systolic diameter (LVDS) were measured at both MV-tip and LV-mid, and the LV end-diastolic volume (LVEDV) and end-systolic volume (LVESV) were quantified using CMRI. We quantified the degree of aortic wedging as the angle between the anterior wall of the aorta and the ventricular septal surface (ASA).

RESULTS

The average LVDD was smaller and average LVDS larger when measured at the MV-tip than at the LV-mid. In regression analyses, the correlation coefficient between LVDD and LVEDV was larger at LV-mid (R = 0.89) than at MV-tip (R = 0.82), and the correlation coefficient between LVDS and LVESV also larger at LV-mid (R = 0.93) than MV-tip (R = 0.87). ASA, Valsalva diameter, left atrial diameter, patient height, and LV mass significantly affected the echocardiographic measurement error, but no factor affected the measurement error when quantifying LVDD at the LV-mid level.

CONCLUSIONS

The echocardiographic LV diameter measured at LV-mid has a stronger correlation with LV chamber size derived from CMRI than measurements at MV-tip. The LVDD measured at the LV-mid level is not affected by other factors.

A thoracic CT imaging parameter predicting access difficulty in acute stroke thrombectomy

PURPOSE

The quick establishment of adequate vascular access is essential for the technical success of mechanical thrombectomy (MT). Focusing on shifts in aortic arch geometry and aging-related changes, we propose an imaging parameter for predicting access difficulty using chest CT.

METHODS

Patients with acute anterior circulation large-vessel occlusion who underwent MT from April 2020 to September 2021 were included in this retrospective multicenter observational study. The distance from the sternum to the ascending aorta (S-AAD) was defined as the surrogate marker of access difficulty. Access was defined as difficult when the time from femoral sheath placement to guiding catheter induction (guiding time: GT) ≥ 30 minutes, and the patients were dichotomized into groups with short GT (sGT: GT < 30 min) and long GT (lGT: GT ≥ 30 min).

RESULTS

One hundred fifteen patients were included. There were 12 patients (10.4 %) in lGT group. The median (IQR) S-AAD was 11.9 mm (6.3, 18.3 mm) in sGT group and 6.6 mm (4.0, 10.3 mm) in lGT group, and a significant difference in S-AAD was observed (P = 0.026). In multivariate analyses, dyslipidemia and S-AAD < 5 mm were significantly associated with difficult access (OR, 5.938 [95 % CI, 1.468, 24.022], P = 0.012 for dyslipidemia; OR, 5.147 [95 % CI, 1.267, 20.917], P = 0.022 for S-AAD < 5 mm).

CONCLUSION

S-AAD is a simple and reliable imaging parameter to predict access difficulty. This parameter may be helpful in selecting the appropriate devices and access routes in preinterventional practice.

A morphological indicator for aortic dissection: fitting circle of the thoracic aorta

BACKGROUND

This study aims to identify a morphological indicator of aortic dissection (AD) based on the geometrical characteristics of the thoracic aorta.

METHODS

We evaluated computed tomographic angiograms of 63 samples with AD (22 with type A AD, 41 with type B AD) and 71 healthy samples. Via centerline extraction and spatial transformation, the spatial entanglement of the aorta was minimized, and the expanded 2D aortic morphology was obtained. The 2D morphology of the thoracic aorta was fit to a circle. The applicability of the fitting circle method for identifying aortic dissection was verified by multivariable logistic regression analysis.

RESULTS

Via the 3D coordinate transformation algorithm, the optimal aortic view was obtained. On this view, the geometrical characteristics of the thoracic aortas of the healthy controls were similar to a portion of a circle (sum of residuals: 3502.45 ± 2566.71, variance: 86.23 ± 56.60), while that of AD samples had poorer similarity to the circle (sum of residuals: 5404.78 ± 3891.69, variance: 129.90 ± 90.09). This difference was significant (p < 0.001). A logistic regression model showed that increased deformation of the thoracic aorta was a significant indicator of aortic dissection (odds ratio: 1.35, p = 0.034).

CONCLUSIONS

The morphology of the healthy thoracic aorta could be fit to a circle, while that of the dissected aorta had poorer similarity to the circle. The statistics of the circle are an effective indicator of aortic deformation in AD.

TRIAL REGISTRATION

This study is registered in the Chinese Clinical Trial Registry (ChiCTR2000029219).

Comprehensive sex-specific and age-dependent analysis of 4D-flow MRI assessed aortic blood flow-related parameters in normal subjects using single-vendor MR systems and single-vendor software

BACKGROUND

Aortic blood flow characterization by 4D flow MRI is increasingly performed in aneurysm research. A limited number of studies have established normal values that can aid the recognition of abnormal flow at an early stage. This study aims to establish additional sex-specific and age-dependent reference values for flow-related parameters in a large cohort of healthy adults.

METHODS

212 volunteers were included, and 191 volunteers completed the full study protocol. All underwent 4D flow MRI of the entire aorta. Quantitative values for velocity, vorticity, helicity, as well as total, circumferential, and axial wall shear stress [WSS] were determined for the aortic root [AoR], ascending aorta [AAo], aortic arch [AoA], descending [DAo], suprarenal [SRA], and infrarenal aorta [IRA]. Vorticity and helicity were indexed for segment volume (mL).

RESULTS

The normal values were estimated per sex- and age-group, where significant differences between males (M) and females (F) were found only for specific age groups. More specifically, the following variables were significantly different after applying the false discovery rate correction for multiple testing: 1) velocity in the AAo and DAo in the 60-70 years age group (mean±SD: (M) 47.0 ± 8.2cm/s vs. (F) 38.4 ± 6.9cm/s, p=0.001 and, (M) 55.9 ± 9.9cm/s vs. (F) 46.5 ± 5.5cm/s, p=0.002), 2) normalized vorticity in AoR in the 50-59 years age group ((M) 27539 ± 5042s-1mL-1 vs. (F) 30849 ± 7285s-1mL-1, p=0.002), 3) axial WSS in the Aao in the 18-29 age group ((M) 1098 ± 203 mPa vs. (F) 921 ± 121 mPa, p=0.002). Good to strong negative correlations with age were seen for almost all variables, in different segments, and for both sexes.

CONCLUSION

This study describes reference values for aortic flow-related parameters as acquired by 4D flow MRI. We observed limited differences between males and females. A negative relationship with age was seen for almost all flow-related parameters and segments.

Tortuosity in non-atherosclerotic vascular diseases is associated with age, arterial aneurysms, and hypertension

BACKGROUND

Increased arterial tortuosity has been associated with various cardiovascular complications. However, the extent and role of arterial tortuosity in non-atherosclerotic vascular diseases remain to be fully elucidated. This study aimed to assess arterial tortuosity index (ATI) in patients with non-atherosclerotic vascular diseases and the associated factors.

METHODS

This is a retrospective analysis of patients with non-atherosclerotic vascular diseases referred to the Malformation and Rare Vascular Disease Center at the University Hospital in Lausanne (Switzerland). Computed tomography angiography (CTA) images performed between October 2010 and April 2022 were retrieved and the aortic tortuosity index (ATI) was calculated. Patients were classified based on diagnosis into the following groups: arterial dissection & aneurysm, arteritis & autoimmune disease, hereditary connective tissue diseases, and fibromuscular dysplasia (FMD). Univariate and multivariate logistic regression analysis was used to determine potentially relevant predictors of aortic tortuosity.

RESULTS

The mean age upon computed tomography angiography (CTA) was 46.8 (standard deviation [SD] 14.6) years and 59.1% of the patients were female. Mean ATI was higher in patients over 60 years old (1.27), in those with arterial aneurysms (mean: 1.11), and in those diagnosed with hypertension (mean: 1.13). When only patients over 60 years old were considered, those diagnosed with connective tissue diseases had the highest ATI. At multivariate regression analysis, increasing age (p < 0.05), presence of arterial aneurysms (p < 0.05), and hypertension (p < 0.05) were independently associated with ATI.

CONCLUSIONS

The ATI may be a promising tool in diagnostic evaluation, cardiovascular risk stratification, medical or surgical management, and prognostic assessment in several non-atherosclerotic vascular conditions. Further studies with longitudinal design and larger cohorts are needed to validate the role of ATI in the full spectrum of vascular diseases.

Three-dimensional aortic geometry: clinical correlates, prognostic value and genetic architecture

Aortic structure and function impact cardiovascular health through multiple mechanisms. Aortic structural degeneration increases left ventricular afterload, pulse pressure and promotes target organ damage. Despite the impact of aortic structure on cardiovascular health, aortic 3D-geometry has yet to be comprehensively assessed. Using a convolutional neural network (U-Net) combined with morphological operations, we quantified aortic 3D-geometric phenotypes (AGPs) from 53,612 participants in the UK Biobank and 8,066 participants in the Penn Medicine Biobank. AGPs reflective of structural aortic degeneration, characterized by arch unfolding, descending aortic lengthening and luminal dilation exhibited cross-sectional associations with hypertension and cardiac diseases, and were predictive for new-onset hypertension, heart failure, cardiomyopathy, and atrial fibrillation. We identified 237 novel genetic loci associated with 3D-AGPs. Fibrillin-2 gene polymorphisms were identified as key determinants of aortic arch-3D structure. Mendelian randomization identified putative causal effects of aortic geometry on the risk of chronic kidney disease and stroke.

Evaluation of the association between the internal carotid artery and vertebral artery tortuosity and acute ischemic stroke using tortuosity index

OBJECTIVE

To determine the association between the tortuosity of the internal carotid artery and vertebral artery and the occurrence of acute ischemic stroke based on a new quantitative method.

METHODS

This retrospective case-control study was conducted on 63 patients diagnosed with acute ischemic stroke in the case group and 52 patients in the control group. All the participants underwent neck Computed Tomography Angiography. The images were retrospectively reviewed and the tortuosity index was measured for internal carotid and vertebral artery. Then, a multivariable binary logistic regression model adjusted for the potential confounders was performed to assess the independent effect of internal carotid/vertebral artery tortuosity on acute ischemic stroke.

RESULTS

Analysis of the logistic regression model revealed a significant effect of the internal carotid artery tortuosity index on anterior territory infarction (odds ratio = 1.04, p = 0.01) as well as a significant effect of the vertebral artery tortuosity index on posterior territory infarction (odds ratio = 1.14, p < 0.001). The optimal cut-off points for the internal carotid and vertebral artery tortuosity were 16.91 and 22.96, respectively.

CONCLUSIONS

This study showed that tortuosity of extracranial portions of the internal carotid and vertebral artery could be an independent imaging predictor of acute ischemic stroke in anterior and posterior circulation territories, respectively.

Computed Tomography Scan of the Aorta to Predict Type B Aortic Dissection

BACKGROUND

 The purpose of this study is to find the high-risk morphological features in type B aortic dissection (TBAD) population and to establish an early detection model.

METHODS

 From June 2018 to February 2022, 234 patients came to our hospital because of chest pain. After examination and definite diagnosis, we excluded people with previous cardiovascular surgery history, connective tissue disease, aortic arch variation, valve malformation, and traumatic dissection. Finally, we included 49 patients in the TBAD group and 57 in the control group. The imaging data were retrospectively analyzed by Endosize (Therevna 3.1.40) software. The aortic morphological parameters mainly include diameter, length, direct distance, and tortuosity index. Multivariable logistic regression models were performed and systolic blood pressure (SBP), aortic diameter at the left common carotid artery (D3), and length of ascending aorta (L1) were chosen to build a model. The predictive capacity of the models was evaluated through the receiver operating characteristic (ROC) curve analysis.

RESULTS

 The diameters in the ascending aorta and aortic arch are larger in the TBAD group (33.9 ± 5.9 vs. 37.8 ± 4.9 mm, p < 0.001; 28.2 ± 3.9 vs. 31.7 ± 3.0 mm, p < 0.001). The ascending aorta was significantly longer in the TBAD group (80.3 ± 11.7 vs. 92.3 ± 10.6 mm, p < 0.001). Besides, the direct distance and tortuosity index of the ascending aorta in the TBAD group increased significantly (69.8 ± 9.0 vs. 78.7 ± 8.8 mm, p < 0.001; 1.15 ± 0.05 vs. 1.17 ± 0.06, p < 0.05). Multivariable models demonstrated that SBP, aortic diameter at the left common carotid artery (D3), and length of ascending aorta (L1) were independent predictors of TBAD occurrence. Based on the ROC analysis, area under the ROC curve of the risk prediction models was 0.831.

CONCLUSION

 Morphological characteristic including diameter of total aorta, length of ascending aorta, direct distance of ascending aorta, and tortuosity index of ascending aorta are valuable geometric risk factors. Our model shows a good performance in predicting the incidence of TBAD.

Impact of an angulated aorto-septal relationship on cardio-cerebrovascular outcomes in patients undergoing hemodialysis

Aortic and valvular calcification are well-known risk factors for cardio-cerebrovascular events in patients undergoing hemodialysis. We investigated the clinical impact of an angulated aorto-septal angle as a result of aortic elongation due to aortic calcification on cardio-cerebrovascular outcomes in patients undergoing hemodialysis. We investigated 306 patients (mean age 65.4 years, 68% male) who underwent pre-scheduled routine echocardiography between April and September 2018. The angle between the anterior wall of the aorta and the ventricular septal surface (ASA) was quantified. We determined aortic and mitral valve calcification scores based on calcified cardiac changes; the aortic and mitral valve scores ranged between 0-9 and 0-6, respectively. The primary endpoint was a composite including cardio-cerebrovascular events and cardio-cerebrovascular death. The mean duration of dialysis among the patients in this analysis was 9.6 years. The primary endpoint was observed in 54 patients during the observational period (median 1095 days). Multivariable Cox proportional hazards analyses identified left ventricular ejection fraction (per 10% increase: hazard ratio [HR] 0.67; 95% confidential interval [CI] 0.53-0.84, P = 0.001), left ventricular mass index (per 10 g/m2 increase: HR 1.14; 95% CI 1.05-1.24, P = 0.001), ASA (per 10 degree increase: HR 0.69; 95% CI 0.54-0.88; P = 0.003), and aortic valve calcification score (HR 1.15; 95% CI 1.04-1.26, P = 0.005) as independent determinants of the primary endpoint. Kaplan-Meier analysis showed a higher incidence of the primary endpoint in patients with ASA <119.4 degrees than those with ASA ≥119.4 degrees (Log-rank P < 0.001). An angulated aorto-septal angle is an independent risk factor for cardio-cerebrovascular events and cardio-cerebrovascular death in patients undergoing hemodialysis.

Elongation of the proximal descending thoracic aorta and associated hemodynamics increase the risk of acute type B aortic dissection

BACKGROUND

Acute type B aortic dissection (ATBAD) is a life-threatening aortic disease. However, little information is available on predicting and understanding of ATBAD.

OBJECTIVE

The study sought to explore the underlying mechanism of ATBAD by analyzing the morphological and hemodynamic characteristics related to aortic length.

METHODS

The length and tortuosity of the segment and the whole aorta in the ATBAD group (n= 163) and control group (n= 120) were measured. A fixed anatomic landmark from the distal of left subclavian artery (LSA) to the superior border of sixth thoracic vertebra was proposed as the proximal descending thoracic aorta (PDTA), and the dimensionless parameter, length ratio, was introduced to eliminate the individual differences. The significant morphological parameters were filtrated and the associations between parameters were investigated using statistical approaches. Furthermore, how aortic morphology influenced ATBAD was explored based on idealized aortic models and hemodynamic-related metrics.

RESULTS

The PDTA length was significantly increased in the ATBAD group compared with the control group and had a strong positive correlation with the whole aortic length (r= 0.89). The length ratio (LR2) and tortuosity (T2) of PDTA in the ATBAD group were significantly increased (0.15 ± 0.02 vs 0.12 ± 0.02 and 1.73 ± 0.48 vs 1.50 ± 0.36; P< 0.001), and LR2 was positive correlation with T2 (r= 0.73). In receiver-operating curve analysis, the area under the curve was 0.835 for LR2 and 0.641 for T2. Low and oscillatory shear (LOS) was positive correlation with LR2, and the elevated LOS occurred in the distal of LSA.

CONCLUSION

Elongation of PDTA is associated with ATBAD, and the length ratio is a novel predictor. Elongated PDTA induced more aggressive hemodynamic forces, and high LOS regions may correspond to the entry tear location. The synergy of the morphological variation and aggressive hemodynamics creates contributory conditions for ATBAD.

Establishing and Validating a Morphological Prediction Model Based on CTA to Evaluate the Incidence of Type-B Dissection

Background: Many patients with Type B aortic dissection (TBAD) may not show noticeable symptoms until they become intervention and help prevent critically ill, which can result in fatal outcomes. Thus, it is crucial to screen people at high risk of TBAD and initiate the necessary preventive and therapeutic measures before irreversible harm occurs. By developing a prediction model for aortic arch morphology, it is possible to accurately identify those at high risk and take prompt action to prevent the adverse consequences of TBAD. This approach can facilitate timely the development of serious illnesses. Method: The predictive model was established in a primary population consisting of 173 patients diagnosed with acute Stanford TBAD, with data collected from January 2017 and December 2018, as well as 534 patients with healthy aortas, with data collected from April 2018 and December 2018. Explicitly, the data were randomly separated into the derivation set and validation set in a 7:3 ratio. Geometric and anatomical features were extracted from a three-dimensional multiplanar reconstruction of the aortic arch. The LASSO regression model was utilized to minimize the data dimension and choose relevant features. Multivariable logistic regression analysis and backward stepwise selection were employed for predictive model generation, combining demographic and clinical features as well as geometric and anatomical features. The predictive model's performance was evaluated by examining its calibration, discrimination, and clinical benefit. Finally, we also conducted internal verification. Results: After applying LASSO logistic regression and backward stepwise selection, 12 features were entered into the prediction model. Age, aortic arch angle, total thoracic aorta distance, ascending aorta tortuosity, aortic arch tortuosity, distal descending aorta tortuosity, and type III arch were protective factors, while male sex, hypertension, aortic arch height, and aortic arch distance were risk factors. The model exhibited satisfactory discrimination (AUC, 0.917 [95% CI, 0.890-0.945]) and good calibration in the derivation set. Applying the predictive model to the validation set also provided satisfactory discrimination (AUC, 0.909 [95% CI, 0.864-0.953]) and good calibration. The TBAD nomogram for clinical use was established. Conclusions: This study demonstrates that a multivariable logistic regression model can be used to predict TBAD patients.

Arterial Tortuosity Syndrome: Unraveling a Rare Vascular Disorder

Arterial tortuosity syndrome (ATS) is a rare genetic disorder characterized by abnormal twists and turns of arteries, leading to cardiovascular complications. This syndrome, first reported around 55 years ago, is inherited in an autosomal recessive manner and affects both genders. ATS manifests primarily in childhood, with arterial abnormalities disrupting blood circulation, increasing shear stress, and causing complications, such as atherosclerosis and strokes. This article reviews the genetics, etiology, pathophysiology, clinical presentation, diagnosis, associated conditions, management, and challenges of ATS. The syndrome's genetic cause is linked to mutations in the SLC2A10 gene, affecting collagen and elastin synthesis. Arterial tortuosity, a complex phenomenon, arises from factors such as vessel elongation, anatomic fixation, and vessel diameter. ATS is one of many conditions associated with arterial tortuosity, including Marfan syndrome and Loeys-Dietz syndrome. Recent studies highlight arterial tortuosity's potential as a prognostic indicator for adverse cardiovascular events. Management requires a multidisciplinary approach, and surveillance and prevention play key roles. Despite challenges, advancements in understanding ATS offer hope for targeted therapies and improved patient care.

A Comparative Study of Clinical and Aortic Morphological Characteristics between Bovine Aortic Arch and Normal Aortic Arch in Patients with Acute Type B Aortic Dissection

INTRODUCTION

The purpose of this study was to analyze the difference in clinical and aortic morphological features between the bovine aortic arch and normal aortic arch in patients with acute type B aortic dissection (aTBAD).

METHODS

A total of 133 patients diagnosed with aTBAD were retrospectively collected. Based on aortic arch morphology, they were divided into the bovine aortic arch group (n = 20) and the normal aortic arch group (n = 113). Aortic morphological features were assessed on computed tomographic angiography. Clinical and aortic morphological features were then compared between the bovine aortic arch and normal aortic arch groups.

RESULTS

Patients in the bovine aortic arch group were significantly younger and with higher weight and BMI than the normal aortic arch group (p < 0.001, p = 0.045, and p = 0.016, respectively). The total aortic length in the bovine aortic arch group was significantly shorter than that in the normal aortic arch group (p = 0.039). The tortuosity of descending thoracic aorta, the tortuosity of descending aorta, and the angulation of aortic arch were significantly lower in the bovine aortic arch group (p = 0.004, p = 0.015, and p = 0.023, respectively). The width of descending aorta, the height of aorta arch, and the angle of ascending aorta were significantly smaller in the bovine aortic arch group (p = 0.045, p = 0.044, and p = 0.042, respectively).

CONCLUSION

When the aTBAD occurred, patients with bovine aortic arch were prone to be younger and with higher BMI than those with normal aortic arch. The aortic curvature and the total aortic length were lower in patients with bovine aortic arch.

Predicting the Risk of Type B Aortic Dissection Using Hemodynamic Parameters in Aortic Arches: A Comparative Study between Healthy and Repaired Aortas

BACKGROUND AND OBJECTIVE

The development of acute aortic dissection (AD) remains unpredictable due to the intricate nature of the AD mechanism and the varied patient-specific aortic anatomy. The aim of this study was to simulate the hemodynamic parameters in the aortas before the onset of TBAD with healthy controls.

METHODS

This study numerically assessed the effectiveness of hemodynamic indicators in predicting the risk of type B AD (TBAD) by investigating the differences in hemodynamic parameters between healthy and repaired aortas (aortas before TBAD development). Four wall shear stress (WSS)-based indicators and three helicity-based indicators were adopted and analyzed.

RESULTS

The results showed that more pathological anatomical feathers can be observed in the repaired aortas. For WSS-based indicators, only averaged cross flow index (CFI) and oscillatory shear index OSI (CFI, 1.03 ± 0.07 vs. 0.83 ± 0.10 and OSI, 0.12 ± 0.03 vs. 0.04 ± 0.02) (all p<0.001) were significantly higher in the repaired aortas than those in the healthy aortas. On the other hand, average helicity in the repaired aortas also showed a significant difference compared with that in healthy aortas (h1, 3.88 ± 5.55 vs. -8.03 ± 14.16) (p<0.05). Furthermore, the skewed helical structure and flow disturbance was found in the repaired aortas.

CONCLUSION

1) There are marked differences in pathological anatomical features, such as aortic dilation, elongation and tortuosity between the healthy aortas and repaired aortas, and the corresponding hemodynamic indicators also have also been significantly changed. 2) Compared with anatomical characteristics, hemodynamic indicators may be more accurate for predicting the risk and location of TBAD, such as the OSI and CFI index were significantly enhanced in the region where the entry tears have occurred. 3) In clinical practice, anatomical features remain important factors for assessing the risk for development of TBAD; however, hemodynamic analyses with quantitative data and more visualizing characteristics have showed promising potential in this aspect.

Helical flow in tortuous aortas and its relationship to turbulence: A whole-aorta 4D flow MRI study

Background

Increased vascular tortuosity is a hallmark of ageing of the vascular system, including the aorta. However, the impact of tortuosity on aortic blood flow is unknown. We hypothesized that increased tortuosity would be associated with increased blood flow helicity and with decreased degree of blood flow turbulence as measured by the turbulent kinetic energy (TKE).

Methods

4D Flow MR images covering the entire aorta from the aortic valve to the iliac bifurcation were acquired in 23 normal volunteers aged 18-30 years ("Young") and 23 normal volunteers aged 66-76 years ("Old") without aortic disease. The aorta was segmented and divided into four regions: the ascending, descending, suprarenal abdominal and infrarenal abdominal aorta. Tortuosity, helicity, TKE, flow velocity, and Reynolds number were computed for the whole aorta and for each section.

Results

Tortuosity and helicity were higher whereas TKE, velocity, and Reynolds number were lower in Old than in Young, for all aortic regions (p < 0.05) except for helicity in the descending aorta. Tortuosity correlated positively with helicity and negatively with TKE for all aortic regions (Spearman rho=±0.45-±0.72, p < =0.002) except for TKE in the ascending aorta. Further, helicity correlated with TKE in the descending, suprarenal abdominal and infrarenal abdominal aorta (Spearman rho=-0.56--0.77).

Conclusion

Tortuosity increases with age and blood flow in tortuous aortas is more helical. Increasing helicity, in turn, is associated with decreasing TKE.

Changes in the relative displacement between the supra-aortic branches with age

BACKGROUND

This study aimed to determine the normal ranges for the height and deflection angle of the aortic arch and the displacement distances between the supra-aortic branches in relation to age, sex, body mass index (BMI), and body surface area (BSA) in adults without aortic disease using non-contrast chest computed tomography (CT).

METHODS

The CT scans of 700 patients were analyzed. We measured the height and deflection angle of the aortic arch based on the lower level of the pulmonary artery bifurcation. The displacement distances between the supra-aortic branches in the coronal and sagittal planes were measured, and the deflection angles between these branches were calculated. Multiple linear regression analysis was used to investigate the associations of age, sex, BMI, and BSA with these aortic arch parameters.

RESULTS

The height of the aortic arch was significantly higher (74 ± 15 mm vs. 65 ± 12 mm, p < 0.001) and the left-posterior displacement distance of the left subclavian artery (LSA) to the innominate artery (IA) was greater in men than that in women. The height and deflection angle of the aortic arch increased with age. The distance by which the LSA was shifted to the left posterior of the left common carotid artery and to the left of the IA increased with age.

CONCLUSION

The normal aging process is accompanied by morphological changes in the aortic arch and relative displacement between the supra-aortic branches. Identifying these parameters could lead to a comprehensive understanding of the anatomy and morphology of the aortic arch.

Comparison of aortic zones for endovascular bleeding control: age and sex differences

PURPOSE

To gain insight into anatomical variations between sexes and different age groups in intraluminal distances and anatomical landmarks for correct insertion of resuscitative endovascular balloon occlusion of the aorta (REBOA) without fluoroscopic confirmation.

MATERIALS

All non-trauma patients receiving a computed tomography angiography (CT-A) scan of the aorta, iliac bifurcation and common femoral arteries from 2017 to 2019 were eligible for inclusion.

METHODS

Central luminal line distances from the common femoral artery (CFA) to the aortic occlusion zones were measured and diameters of mid zone I, II and III were registered. Anatomical landmarks and correlations were assessed. A simulated REBOA placement was performed using the Joint Trauma System Clinical Practice Guideline (JTSCPG).

RESULTS

In total, 250 patients were included. Central luminal line (CLL) measurements from mid CFA to aortic bifurcation (p = 0.000), CLL measurements from CFA to mid zone I, II and III (p = 0.000) and zone I length (p = 0.000) showed longer lengths in men. The length of zone I and III (p = 0.000), CLL distance measurements from the right CFA to mid zone I (p = 0.000) and II (p = 0.013) and aortic diameters measured at mid zone I, II and III increased in higher age groups (p = 0.000). Using the JTSCPG guideline, successful deployment occurred in 95/250 (38.0%) in zone III and 199/250 (79.6%) in zone I. Correlation between mid-sternum and zone I is 100%. Small volume aortic occlusion balloons (AOB) have poor occlusion rates in zone I (0-2.8%) and III (4.4-34.4%).

CONCLUSIONS

Men and older age groups have longer CLL distances to zone I and III and introduction depths of AOB must be adjusted. The risk of not landing in zone III with standard introduction depths is high and balloon position for zone III REBOA is preferably confirmed using fluoroscopy. Mid-sternum can be used as a landmark in all patient groups for zone I. In older patients, balloon catheters with larger inflation volumes must be considered for aortic occlusion.

Risk evaluation of type B aortic dissection based on WSS-based indicators distribution in different types of aortic arch

BACKGROUND AND OBJECTIVE

The underlying mechanism of aortic dissection (AD) remains unclear and the onset of AD is still unpredictable. Although clinical study with statistical analysis has reported that type III aortic arch may have strong correlation with type B AD (TBD), the effects of different arch types on the wall shear stress (WSS) have not been clarified.

METHODS

As a complementary work, this study numerically investigated the distribution of five WSS-based indicators in thirty aortic arches without AD, which were classified into three groups based on the arch types.

RESULTS

The distribution of most WSS indicators, such as time averaged WSS (TAWSS), oscillatory shear index (OSI) and relative residence time (RRT) had no significant difference among different types of aortic arches (P>0.05). However, a multidirectional WSS index, namely CFI, was found its maximum value was positively correlated with type III aortic arch in proximal descending aorta (p<0.001, r = 0.65).

CONCLUSIONS

It can be concluded that the enhancement or oscillation of WSS may not be the main reason of TBD is prevalence in type III arches, while the multidirectional WSS distribution may be an important factor. It can be further referred that the CFI may have a potential to predict the onset of TBD.

Unexpected Bare Metal Stent Migration Associated With Aortic Remodeling After PETTICOAT Technique for Aortic Dissection

PURPOSE

To report a unique case of bare metal stent migration in the overlapping zone and subsequent distal stent graft-induced new entry (SINE) after the Provisional Extension to Induce a Complete Attachment (PETTICOAT) technique for aortic dissection.

CASE REPORT

A 67-year-old man underwent thoracic endovascular aortic repair (TEVAR) using the PETTICOAT technique for acute complicated type B aortic dissection. The postoperative course was uneventful, and follow-up computed tomography (CT) showed not only favorable aortic remodeling but also progressive bare metal stent migration in the overlapping zone between the stent graft and the bare metal stent. A 6-month postoperative CT revealed a distal SINE, and the patient underwent re-TEVAR to cover the new entry. Postoperative CT demonstrated successful repair of the distal SINE. The patient is currently in good health 2 years after the reintervention.

CONCLUSION

Surgeons should consider the potential risk of device migration due to favorable aortic remodeling after TEVAR for aortic dissection, especially with the use of additional bare metal stents.

Aortic Geometric Alteration Associated With Acute Type B Aortic Dissection: Angulation, Tortuosity, and Arch Type

Background: Acute type B aortic dissection is a highly serious aortic pathology. Aortic geometric parameters may be useful variables related to the occurrence of acute type B aortic dissection (aTBAD). The aim of the study is to delineate the alteration in aortic geometric parameters and analyze the specific geometric factors associated with aTBAD.

Methods: The propensity score matching method was applied to control confounding factors. The aortic diameter, length, angulation, tortuosity, and type of aortic arch of the aTBAD and control group were retrospectively analyzed via three-dimensional computed tomography imaging created by the 3mensio software (version 10.0, Maastricht, The Netherlands). The geometric variables of true lumen and false lumen in the descending aorta were measured to estimate the severity of aortic dissection. Multivariable logistic regression models were used to investigate the significant and specific factors associated with aTBAD occurrence. The area under the receiver operating characteristic curve (AUC) was used to estimate the performance of the model.

Results: After propensity score matching, 168 matched pairs of patients were selected. The ascending aorta and aortic arch diameters were dilated, and the ascending aorta and total aorta lengths were elongated in aTBAD group significantly (P < 0.001). The ascending aorta and aortic arch angulations in the aTBAD group were sharper than those of the controls (P = 0.01, P < 0.001, respectively). The aortic arch and total aorta tortuosities were significantly higher in the aTBAD group (P = 0.001, P < 0.001, respectively). There were more type III arch patients in the aTBAD group than the controls (67.9 vs. 22.6%). The true lumen angulation was sharper than that in the false lumen (P < 0.01). The true lumen tortuosity was significantly lower than that in the false lumen (P < 0.001). The multivariable models identified that aortic arch angulation, tortuosity, and type III arch were independent and specific geometric factors associated with aTBAD occurrence. The AUC of the multivariable models 1, 2, 3 were 0.945, 0.953, and 0.96, respectively.

Conclusions: The sharper angulation and higher tortuosity of aortic arch and type III arch were the geometric factors associated with aTBAD in addition to the ascending aorta elongation and aortic arch dilation. The angulation and tortuosity of the true and false lumens may carry significant clinical implications for the treatment and prognosis of aTBAD.

Effects of Exercise and Weight Loss on Proximal Aortic Stiffness in Older Adults With Obesity

BACKGROUND

Obesity may accelerate age-related increases in aortic stiffness. Although aerobic exercise training generally has favorable effects on aortic structure and function, exercise alone may not be sufficient to improve aortic stiffness in older adults with obesity. We determined the effects of aerobic exercise training with and without moderate- to high-caloric restriction (CR) on the structure and function of the proximal aorta in 160 older (65-79 years) men and women with obesity (body mass index=30-45 kg/m²).

METHODS

Participants were randomly assigned to 1 of 3 groups: aerobic exercise training only (treadmill 4 days/week for 30 minutes at 65% to 70% of heart rate reserve; n=56), aerobic exercise training plus moderate CR (n=55), or aerobic exercise training plus more intensive CR (n=49) for 20 weeks. Aortic pulse wave velocity, aortic distensibility, and other measures of aortic structure and function were assessed by cardiovascular magnetic resonance imaging. Pearson correlation coefficients were examined to assess associations between changes in proximal aortic stiffness and changes in fitness, fatness, and other potential confounders.

RESULTS

Weight loss in the aerobic exercise training plus moderate CR (-8.0 kg [95% CI, -9.17 to -6.87]) and aerobic exercise training plus more intensive CR (-8.98 kg [95% CI, -10.23 to -7.73) groups was significantly greater compared with the aerobic exercise training-only group (-1.66 kg [95% CI, -2.94 to -0.38]; P<0.017 for both). There were significant treatment effects for descending aorta distensibility (P=0.008) and strain (P=0.004) and aortic arch pulse wave velocity (P=0.01) with the aerobic exercise training plus moderate CR group having a 21% increase in distensibility (P=0.016) and an 8% decrease in pulse wave velocity (P=0.058). None of the aortic stiffness measures changed significantly in the aerobic exercise training-only or aerobic exercise training plus more intensive CR groups, and there were no significant changes in any other measure of aortic structure or function in these groups. Overall, increases in aortic distensibility were correlated with improvements in body weight and body fat distribution, but these associations were not statistically significant after adjustment for multiple comparisons.

CONCLUSIONS

In older adults with obesity, combining aerobic exercise with moderate CR leads to greater improvements in proximal aortic stiffness than exercise alone. Registration: URL: https://clinicaltrials.gov; Unique identifier: NCT01048736.

Characterization of Ascending Aortic Flow in Patients With Degenerative Aneurysms: A 4D Flow Magnetic Resonance Study

OBJECTIVES

Degenerative thoracic aortic aneurysm (TAA) patients are known to be at risk of life-threatening acute aortic events. Guidelines recommend preemptive surgery at diameters of greater than 55 mm, although many patients with small aneurysms show only mild growth rates and more than half of complications occur in aneurysms below this threshold. Thus, assessment of hemodynamics using 4-dimensional flow magnetic resonance has been of interest to obtain more insights in aneurysm development. Nonetheless, the role of aberrant flow patterns in TAA patients is not yet fully understood.

MATERIALS AND METHODS

A total of 25 TAA patients and 22 controls underwent time-resolved 3-dimensional phase contrast magnetic resonance imaging with 3-directional velocity encoding (ie, 4-dimensional flow magnetic resonance imaging). Hemodynamic parameters such as vorticity, helicity, and wall shear stress (WSS) were calculated from velocity data in 3 anatomical segments of the ascending aorta (root, proximal, and distal). Regional WSS distribution was assessed for the full cardiac cycle.

RESULTS

Flow vorticity and helicity were significantly lower for TAA patients in all segments. The proximal ascending aorta showed a significant increase in peak WSS in the outer curvature in TAA patients, whereas WSS values at the inner curvature were significantly lower as compared with controls. Furthermore, positive WSS gradients from sinotubular junction to midascending aorta were most prominent in the outer curvature, whereas from midascending aorta to brachiocephalic trunk, the outer curvature showed negative WSS gradients in the TAA group. Controls solely showed a positive gradient at the inner curvature for both segments.

CONCLUSIONS

Degenerative TAA patients show a decrease in flow vorticity and helicity, which is likely to cause perturbations in physiological flow patterns. The subsequent differing distribution of WSS might be a contributor to vessel wall remodeling and aneurysm formation.

Excess of visceral adipose tissue with or without aortic elongation leads to a steeper heart position

BACKGROUND

The heart's position determined as the heart-aorta angle (HAA) has been demonstrated to associate with ascending aortic (AA) dilatation. Visceral adipose tissue (VAT) and aortic elongation may shift the heart to the steeper position.

PURPOSE

To investigate whether VAT and aortic length influence the HAA.

MATERIAL AND METHODS

We examined 346 consecutive patients (58.4% men; mean age = 67.0 ± 14.1 years) who underwent aortic computed tomography angiography (CTA). HAA was measured as the angle between the long axis of the heart and AA midline. The amount of VAT was measured at the level of middle L4 vertebra from a single axial CT slice. Aortic length was measured by combining four anatomical segments in different CTA images. The amount of VAT and aortic length were determined as mild with values in the lowest quartile and as excessive with values in the other three quartiles.

RESULTS

A total of 191 patients (55.2%) had no history of aortic diseases, 134 (38.7%) displayed AA dilatation, 8 (2.3%) had abdominal aortic aneurysm (AAA), and 13 (3.8%) had both AA dilatation and AAA. There was a strong nonlinear regression between smaller HAA and VAT/height, and HAA and aortic length/height. Median HAA was 124.2° (interquartile range 119.0°-130.8°) in patients with a mild amount of VAT versus 120.5° (interquartile range 115.4°-124.7°) in patients with excessive VAT (P < 0.001).

CONCLUSION

An excessive amount of VAT and aortic elongation led to a steeper heart position. These aspects may possess clinical value when evaluating aortic diseases in obese patients.

Morphological Features of Aortic Arch Predicting the Risk for Acute Type B Aortic Dissection

BACKGROUND

The purpose of the study is to elucidate the changes in aortic morphological parameters and identify the specific geometric risk factors associated with aTBAD.

METHODS

A total of 167 patients in aTBAD group and 196 subjects in control group were enrolled in the study. The aortic morphological data were retrospectively analyzed by 3mensio Vascular software. The aortic morphological parameters include diameter, length, angulation, tortuosity and the type of aortic arch. Multivariable logistic regression models were developed to identify the significant predictors associated with the angulation, tortuosity and aortic arch type. The predictive capacity of the models was evaluated through the receiver operating characteristic (ROC) curve analysis.

RESULTS

The diameters in the ascending aorta and aortic arch and the lengths in the ascending aorta and total aorta were significantly greater in aTBAD group. Besides, the angulation of the ascending aorta and aortic arch in aTBAD group increased significantly. The tortuosity of aortic arch and total aorta was significantly higher in aTBAD group. The prevalence of type III arch in aTBAD group was significantly higher than that in the controls. Multivariable models demonstrated that aortic arch angulation, tortuosity and type III arch were independent geometric predictors of aTBAD occurrence. Based on the ROC analysis, AUC of the risk prediction models was 0.977, 0.958 and 0.945, respectively.

CONCLUSIONS

Besides the enlargement of the ascending aorta and aortic arch, incremental aortic arch angulation, tortuosity and type III arch configuration are valuable geometric risk factors that could enhance aTBAD incidence.

Understanding the Aorta-Spine Relation in Idiopathic Scoliosis: Value of Noncontrast CT-Derived Curved Coronal Reformats and 3D Volume Images

BACKGROUND

Investigating axial position and longitudinal bending of the aorta in relation to spine curvature in adolescent idiopathic scoliosis patients could help surgeons in planning of spine surgeries.

METHODS

Noncontrast computed tomography (CT) scans of 27 consecutive patients with adolescent idiopathic scoliosis (19 right and 8 left curves) and 16 control subjects were retrospectively reviewed. Using semiautomated software, centerline was drawn along the descending aorta, and curved reformat was generated. Aorta tortuosity index (TI) was calculated as (centerline length/straight line distance) - 1 × 100. The spine centerline was drawn from T1 to L5, and curve index (CI) was similarly calculated. The aorta centerline angle was measured. Apical vertebral-rotation angle and multilevel aorto-vertebral angles were measured on axial CT. Three-dimensional volume-rendered images of the aorta were generated using a manual region grow function.

RESULTS

Mean (± standard deviation) Cobb's angle was 63.8 ± 34.6°. The spine CI of patients (9.7 ± 7.11) was significantly higher than controls (0.28 ± 0.22), P = .00001. Aorta TI in scoliosis was significantly higher than controls (6.4 ± 7.2 versus 0.6 ± 0.5, P = .0001). The aorta centerline angle was steeper in scoliosis than controls (140 ± 26.8° versus 170 ± 3.6°). Correlations were excellent between the aorta TI and each of Cobb's angle, spine CI, and vertebral rotation angle (r = 0.851 to 0.867, all P < .001). Aorto-vertebral angles were significantly different between right scoliosis and left scoliosis patients and control groups at T6, T7, T8, L2, and L3 levels.

CONCLUSIONS

Aortic curvature increases in proportion to the degree of scoliosis. The aorta follows the concavity of scoliosis in right and left curves. In the axial CT plane, the aorta in both right and left scoliosis is maximally rotated away from its normal position at T7 and is closest to its normal position at T11 to T12.

CLINICAL RELEVANCE

Quantitative evaluation of aortic curvature combined with preoperative reconstructed CT images could be beneficial for surgeons in planning of spine surgeries.

Implications of abnormal ascending aorta geometry for risk prediction of acute type A aortic dissection

OBJECTIVES

Recently, increased length of the ascending aorta has been suggested as a possible risk factor for acute type A aortic dissection (ATAAD). Our goal was to identify measurable aortic geometrical characteristics associated with elongation that could differentiate ATAAD from uncomplicated aortic dilation (>45 mm).

METHODS

In angiographic computed tomography scans performed in 180 patients having cardiac surgery, aortic diameters, root length, length of the ascending aorta at both the centreline and the greater curvature (convexity) and the root-ascending (root-asc) angle (that between the root axis and the axis of the ascending tract) and the ascending-arch (asc-arch) angle (that between the axis of the ascending aorta and the arch axis) were measured and compared among 3 patient groups: normal aorta (diameter < 45 mm), dilation/aneurysm (>45 mm) and ATAAD. Correlations between diameters and angles, diameters and lengths and lengths and angles were analysed; multivariable analysis including geometrical factors was performed to identify independent predictors of ATAAD.

RESULTS

Both patients with aneurysms and patients with ATAAD showed significantly elongated ascending aortas (P < 0.001 vs normal). However, in the aneurysms, the root-asc angle (136° ± 20° vs 147° ± 17°; P < 0.001) and in ATAAD the asc-arch angle were uniquely narrower than that in the normal aorta (116° ± 11° vs 132° ± 19°; P < 0.001). All patients with an ATAAD had an asc-arch angle ≤130°. Both in patients with ATAAD and in those without ATAAD, narrowing of the asc-arch angle was associated with elongation of the root segment (P < 0.001). In multivariable analysis, the asc-arch angle and the total length of the ascending aorta (root + tubular) were significant predictors of ATAAD.

CONCLUSIONS

The asc-arch angle is a promising measurement that could help predict aortic dissection along with aortic diameter and length: further verification is warranted.

Mitral prolapsing volume is associated with increased cardiac dimensions in patients with mitral annular disjunction

Introduction

In patients with mitral annular disjunction (MAD), it can be difficult to assess the severity of mitral regurgitation (MR), as they present with a prolapsing volume (i.e. volume resulting from mitral valve prolapse, blood volume shift) rather than a regurgitant jet. The influence of the mitral prolapsing volume (MPV) on cardiac dimensions is unknown. We hypothesised that the severity of MR is underestimated in these patients. Our aim was to measure MPV and to investigate its influence on cardiac dimensions in patients with MAD.

Methods

We retrospectively included 131 consecutive patients with MAD from our institution’s echocardiographic database. Transthoracic echocardiography was used to assess MPV. Additionally, we established a control group of 617 consecutive patients with degenerative mitral valve disease and performed propensity score matching.

Results

Median MPV in the MAD group was 12 ml. MPV was an independent predictor for left ventricular end-diastolic (LVEDD) and end-systolic diameter (LVESD) and left atrial volume (all p < 0.001). In patients with large prolapsing volumes (> 15 ml), LVEDD (56 ± 6 mm vs 51 ± 6 mm, p < 0.001), LVESD [38 mm (34–41) vs 34 mm (31–39), p < 0.01] and left atrial volume [105 ml (86–159) vs 101 ml (66–123), p = 0.04] were significantly increased compared to matched patients with degenerative mitral valve disease and similarly assessed severity of MR.

Conclusion

Due to a volume shift based on the MPV rather than an actual regurgitant jet, MR severity cannot be assessed adequately in MAD patients. Increased MPV induces ventricular and atrial enlargement. These findings warrant future studies to focus on MPV as an additional parameter for assessment of the severity of MR in MAD patients.

Supplementary Information

The online version of this article (10.1007/s12471-021-01575-6) contains supplementary material, which is available to authorized users.

Adherence to instruction for use after endovascular repair of popliteal artery aneurysm

OBJECTIVES

Endovascular repair (ER) of popliteal artery aneurysm (PAA) is an alternative to open repair. However, there is no standardized protocol for when to opt for ER and the decision is therefore at the discretion of the clinician. This study aims to evaluate the adherence to the Instruction For Use (IFU) in patients undergoing ER for PAA and factors associated with stent graft patency at one year.

METHODS

The adherence to IFU provided by the manufacturer in 55 patients treated with Gore Viabahn® Endoprosthesis with Heparin Bioactive Surface for PAA between 2009 and 2019 were retrospectively analyzed. Duplex follow-up was performed at 30 days and one year.

RESULTS

The two groups of patients treated within (n = 10) and not within (n = 45) IFU did not differ in patient demographics, diagnostic assessment, treatment or outcome. Forty-five patients (81.8%) received stent graft placement with at least one deviation according to IFU. Distal oversizing >20% was the most frequent deviation against IFU (n = 22, 40.0%). Primary patency at one year was 72%. Diameter size difference >1 mm between overlapping stent grafts (6/14 [43%], p = 0.013) and renal insufficiency (5/12 [42%], p = 0.0086) were associated with lower primary patency at one year. Age-adjusted analysis of tortuosity index (HR 1.78/SD, 95% CI 1.17-2.71; p = 0.0071) and maximal PAA angle (HR 1.73/SD, 95% CI 1.018-2.95; p = 0.043) were associated with major amputation/mortality at end of follow-up.

CONCLUSION

The majority of patients undergoing ER for PAA were not treated within IFU. Diameter size difference >1 mm between overlapping stent grafts was associated with a higher loss of primary patency at one year. Multi-center studies with larger sample size and long-term follow up of patency are warranted.

Quantitative magnetic resonance imaging measures of three-dimensional aortic morphology in healthy aging and hypertension

Automated segmentation of three-dimensional (3D) aortic magnetic resonance imaging (MRI) renders a possible retrospective selection of any location to perform quantification of aortic caliber perpendicular to its centerline and provides regional and global 3D biomarkers such as length, diameter, or volume. However, normative age-related values of such measures are still lacking. The aim of this study was to provide normal values for 3D aortic morphological measures and investigate their changes in aging and hypertension. This was a retrospective study, in which 119 healthy controls (HC: 48 ± 14 years, 61 men) and 82 hypertensive patients (HT: 60 ± 14 years, 43 men) were enrolled. 1.5 and 3 T/3D steady state free precession or spoiled gradient echo were used. Automated 3D aortic segmentation provided aortic length, diameter, volume for the ascending (AAo), and descending aorta (DAo), along with cross-sectional diameters at three aortic landmarks. Age, sex, body surface area (BSA), smoking, and blood pressures were recorded. Both groups were divided into two subgroups (≤50 years, >50 years). Statistical tests performed were linear regression for age-related normal values and confidence intervals, Wilcoxon rank sum test for differences between groups (HC or HT), and multivariate analysis to identify main determinants of aortic morphological changes. In HC, linear regression revealed an increase in the AAo (respectively DAo) length by 2.84 mm (7.78 mm), maximal diameter by 1.36 mm (1.29 mm), and volume by 4.28 ml (8.71 ml) per decade. AAo morphological measures were higher in HT patients than in HC both ≤50 years but did not reach statistical significance (length: +2 mm, p = 0.531; diameter: +1.4 mm, p = 0.2936; volume:+6.8 ml, p = 0.1857). However, length (+6 mm, p = 0.003), maximal diameter (+4 mm, p < 0.001) and volume (+12 ml, p < 0.001) were significantly higher in HT patients than in HC, both >50 years. In a multivariate analysis, age, sex, and BSA were the major determinants of aortic morphology, irrespective of the presence of hypertension. Global and segmental aortic length, volume, and diameters at specific landmarks were automatically measured from 3D MRI to serve as normative measures of 3D aortic morphology. Such indices increased significantly with age and hypertension among the elderly subjects. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY STAGE: 3.

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

Background

The 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.

Methods

This 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.

Results

The 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.

Conclusions

This study demonstrates that TBAD was associated with longer lengths of aortic arch and with larger arch height and width.

Dysregulation of Endothelial Nitric Oxide Synthase Does Not Depend on Hemodynamic Alterations in Bicuspid Aortic Valve Aortopathy

Background

Bicuspid aortic valves (BAVs) predispose to ascending aortic aneurysm. Turbulent blood flow and genetic factors have been proposed as underlying mechanisms. Endothelial nitric oxide synthase (eNOS) has been implicated in BAV aortopathy, and its expression is regulated by wall shear stress. We hypothesized that if turbulent flow induces aneurysm formation in patients with a BAV, regional differences in eNOS expression would be observed in BAVs.

Methods and Results

Ascending aortic specimens were harvested intraoperatively from 48 patients with tricuspid aortic valve (19 dilated, 29 nondilated) and 38 with BAV (28 dilated, 10 nondilated) undergoing cardiac surgery. eNOS mRNA and protein concentration were analyzed at the convex and concave aortic wall. In nondilated aortas, eNOS mRNA and protein concentration were decreased in BAV compared with tricuspid aortic valve (all P<0.05). eNOS expression was increased in association with dilation in BAV aortas (P=0.03), but not in tricuspid aortic valve aortas (P=0.63). There were no regional differences in eNOS mRNA or protein concentration in BAV aortas (all P>0.05). However, eNOS expression was increased at the concave wall (versus convexity) in tricuspid aortic valve dilated aortas (all P<0.05).

Conclusions

Dysregulated eNOS occurs independent of dilation in BAV aortas, suggesting a potential role for aberrantly regulated eNOS expression in the development of BAV‐associated aneurysms. The absence of regional variations of eNOS expression suggests that eNOS dysregulation in BAV aortas is the result of underlying genetic factors associated with BAV disease, rather than changes stimulated by hemodynamic alterations. These findings provide insight into the underlying mechanisms of aortic dilation in patients with a BAV.

Surgical management of the aorta in BAV patients

Patients with a bicuspid aortic valve (BAV) frequently develop aneurysms of the aortic root and tubular ascending aorta. Aneurysms of the aortic arch, in the absence of concomitant aortopathies, are much less common. According to the 2018 American Association of Thoracic Surgery consensus guidelines on BAV-related aortopathy, prophylactic surgical aortic repair / replacement is recommended starting at a maximum aortic diameter of 50 mm in patients with risk factors. Concomitant aortic surgery is also recommended at an aortic diameter of 45 mm in those patients with other indications for cardiac surgery (most commonly aortic valve procedures). The ultimate goal of prophylactic aortic surgery is the prevention of aortic catastrophes, e.g. aortic rupture or acute aortic dissection, which are associated with high morbidity and mortality. The surgical technique used - in elective and emergency cases - depends on the involvement and nature of the aortic valve disease, as well as the extent of aortic aneurysm formation. The current review focusses on the surgical management of the aortic root, tubular ascending aorta, and proximal aortic arch in BAV patients. Despite the abovementioned recommendations, many BAV patients develop acute aortic syndromes below the recommended aortic diameter thresholds. Further research is therefore required in order to identify high-risk BAV subgroups that would benefit from earlier surgical repair.

Arterial stiffness and multiple organ damage: a longitudinal study in population

AIMS

Previous cross-sectional observation identified arterial aging, indexed as pulse-wave velocity (PWV), as a key determinant of the simultaneous multiple organ damage (heart, carotid artery, and kidney). The aim of the present cohort study is to investigate trajectories of repeated measures of PWV and traditional CV risk factors in subjects who eventually presented clinical evidence of multiple organ damage in the SardiNIA study.

METHODS AND RESULTS

Organ damage was measured in the heart (left ventricular hypertrophy, LVH), the common carotid artery (intima-media thickness > 0.9 mm and/or plaque), and the kidney (eGFR < 60 ml/min/1.73 m²) of 2130 men and women of a broad age range participating the SardiNIA study. SHATS was defined as the simultaneous occurrence of all the three-organ damages. Trajectory in traditional CV risk factors and PWV was analyzed retrospectively (four observations over 9 years) according to the number of organ damage (from 0 to 3). Compared to subjects with no organ damage, after controlling for traditional CV risk factors, each 1 m/s increase in baseline PWV was accompanied by a 93% higher odds of developing SHATS; and each 1 cm/s (0.01 m/s) annual increase in PWV by a 31% greater odds of developing SHATS.

CONCLUSIONS

Arterial stiffness, a proxy of arterial aging that can be measured clinically as PWV, is an integrated predictive marker of multiple age-associated organ damage recognized as clinical diseases.

A smaller heart-aorta-angle associates with ascending aortic dilatation and increases wall shear stress

OBJECTIVES

The aim of this study was to evaluate whether the orientation of the heart, measured as an angle between the long axis of the heart and ascending aorta midline (heart-aorta-angle, HAA), associates with ascending aortic (AA) dilatation. Furthermore, the association between HAA and wall shear stress (WSS) was studied.

METHODS

HAA was retrospectively measured in 1000 consecutive coronary artery computed tomographic angiography (CCTA) images in patients with low-to-moderate pretest probability for coronary artery disease (CAD). To evaluate the effects of HAA on AA flow, 4D flow MRI was performed for 28 patients with AA dilatation (> 40 mm) and WSS was analyzed.

RESULTS

The mean age of patients undergoing CCTA was 52.9 ± 9.8 years; 66.5% were women. Their median HAA was 128.7° and interquartile range 123.3-134.1°. HAA was significantly smaller in patients with dilated AA (median 126.7° [121.3-130.8°]) compared with the patients with normal AA (median 129.5° [124.3-135.3°], p < 0.001). HAA was smaller in males (p < 0.001) and in patients with diabetes (p = 0.016), hypertension (p = 0.001), CAD (p = 0.003), hypercholesterolemia (p < 0.001), and bicuspid aortic valve (p = 0.025) than without these factors. In a subpopulation without any of these underlying diseases (n = 233), HAA was still significantly smaller in the patients with dilated AA (median 127.9° [124.3-134.3°]) compared with patients with normal AA (median 131.9° [127.6-136.9°], p = 0.013). In 4D flow MRI, a smaller HAA correlated with increased total WSS in the outer curvature of the proximal AA (r = - 0.510, p = 0.006).

CONCLUSION

A smaller HAA associates with AA dilatation and affects the blood flow in the proximal AA.

KEY POINTS

• A smaller angle between the long axis of the heart and ascending aorta midline associated with ascending aortic dilatation. • A smaller heart-aorta-angle correlated with increased total wall shear stress in the outer curvature of the proximal ascending aorta.

Changes in the Normal Infrarenal Aortic Length and Tortuosity in Elderly People

Purpose

To investigate the changes in the infrarenal aortic length and tortuosity in elderly patients.

Materials and Methods

We retrospectively reviewed the medical records and computed tomography (CT) scans of 857 patients who underwent surgery for colorectal cancer between August 2009 and July 2012. Among these patients, 48 patients who were aged ≥60 years, underwent follow-up CT at least 5 years after surgery, did not have aortic disease, and did not receive radiation therapy were enrolled. The aortic tortuosity index (ATI) was defined by dividing the distance along the central lumen line from the lowest renal artery to the aortic bifurcation (L1) by the straight-line distance from the lowest renal artery to the aortic bifurcation (L2). Aortic diameters were measured at the lowest renal artery level (D1) and 20 mm below (D2). A paired t-test and Wilcoxon signed-rank test were used to compare lengths and diameters between the initial and final CT scan. Spearman’s correlation analysis was performed to determine the correlations between time and the changes in L1 and ATI.

Results

The average follow-up period was 68 months. The mean changes in L1 and L2 were 0.69 mm and –0.59 mm, respectively, while the mean changes in D1 and D2 were 0.77 mm and 0.58 mm, respectively. The mean increase in ATI was 0.015. All findings were statistically significant. On Spearman’s correlation analysis, ΔL1 and ΔATI showed no correlation with follow-up duration.

Conclusion

The infrarenal aortic length and tortuosity of elderly patients increases at a slow rate over time.

Evaluating the diagnostic accuracy of maximal aortic diameter, length and volume for prediction of aortic dissection

OBJECTIVE

Management of thoracic aortic aneurysms (TAAs) comprises regular diameter follow-up until the indication criterion for prophylactic surgery is reached. However, this approach is unable to predict the majority of acute type A aortic dissections (ATAADs). The current study aims to evaluate the diagnostic accuracy of ascending aortic diameter, length and volume for occurrence of ATAAD.

METHODS

This two-centre observational cohort study retrospectively screened 477 consecutive patients who presented with ATAAD between 2009 and 2018. Of those, 25 (5.2%) underwent CT angiography (CTA) within 2 years before dissection onset. Aortic diameter, length and volume of these patients ('pre-ATAAD') were compared with those of TAA controls (n=75). Receiver operating curve analysis was performed to evaluate the predictive accuracy of the three different measurements.

RESULTS

96% of patients with pre-ATAAD did not meet the surgical diameter threshold of 55 mm before dissection onset. Maximal aortic diameters (45 (40-49) mm vs 46 (44-49) mm, p=0.075) and volume (126 (95-157) cm³ vs 124 (102-136) cm³, p=0.909) were comparable between patients with pre-ATAAD and TAA controls. Conversely, ascending aortic length (84±9 mm vs 90±16 mm, p=0.031) was significantly larger in patients with pre-ATAAD. All three parameters had an area under the curve of >0.800. At the 55 mm cut-off point, the maximal diameter yielded a positive predictive value (PPV) of 20%. While maintaining same specificity levels, measurements of aortic volume and length showed superior diagnostic accuracy (PPV 55% and 70%, respectively).

CONCLUSION

Measurements of aortic volume and length have superior diagnostic accuracy compared with the maximal diameter and could improve the timely identification of patients at risk for ATAAD.

Ascending aortic elongation and correlative change in overall configuration of the proximal aorta in elderly patients with severe aortic stenosis

BACKGROUND

Configurational changes in the proximal aorta are relevant to the procedural difficulty of transcatheter aortic valve implantation (TAVI). Among several morphological changes involving the ascending aorta, elongation is characteristics of elderly patients with aortic stenosis and can compromise the success and safety of TAVI. However, the effect of ascending aortic elongation on the overall morphology of the proximal aorta has not been established.

AIMS

Our primary purpose was to investigate the effect of ascending aortic elongation on structural changes in the proximal aorta in TAVI candidates.

MATERIALS & METHODS

In total, 121 consecutive patients with severe aortic stenosis (mean age, 84.5 ± 5.3 years; 69% women) who had undergone preprocedural computed tomography before TAVI were enrolled. We examined the structural anatomy of the proximal aorta in detail, focusing on its elongation, dilatation, tilting, rotation, and wedging.

RESULTS

The mean length of the ascending aorta was 68.0 ± 9.2 mm, and the length was significantly correlated with dilatation (R = .278, p = .002), rightward tilting (R = .437, p < .001), clockwise rotation (R = .228, p = .018), and deep wedging (R = -.366, p < .001) of the proximal aorta. Elongation of the ascending aorta was correlated with dilatation, rightward tilting, clockwise rotation, and deep wedging of the proximal aorta in an elderly population with severe aortic stenosis.

DISCUSSION

Appreciation of the clinical anatomy around the proximal aorta is required for clinicians involved in TAVI to estimate the procedural difficulty.

CONCLUSION

Elongation of the ascending aorta was associated with dilatation, rightward tilting, clockwise rotation, and deep wedging of the proximal aorta.

Elongation of the Aorta after Thoracic Endovascular Aortic Repair: A longitudinal study

Aortic morphology is associated with age, with the diameter being larger in older people. Thoracic endovascular aortic repair (TEVAR) is a treatment for aortic diseases, such as aortic dissection. When evaluating patients, aortic elongation could interfere with the classification of TEVAR complications. The longitudinal change in aortic length has not been studied in detail. In patients receiving thoracic endovascular aortic repair between 2007 and 2013, we determined the aortic length between the sinotubular junction, left common carotid artery, subclavian artery, and celiac artery on their first five annual follow-up computed tomography (CT) exams. Using the immediate post-TEVAR follow-up CT as the comparison reference and a lengthening of the aortic segment by 10 mm or more as the definition of elongation, 16 of 41 (39%) showed elongation between the innominate artery and celiac artery. When compared with the immediate follow-up CT, a higher proportion of patients showed elongation at the fifth year’s follow-up CT than the first year’s follow-up CT (p < 0.01), and the average lengthening per year was 1.7 mm. There was progressive lengthening of the aorta after TEVAR.

Sexo e idade e sua influência sobre a anatomia da aorta abdominal e seus ramos

Resumo Contexto Não se sabe ao certo como a idade e o sexo do paciente influenciam na anatomia da aorta abdominal e de seus ramos. Objetivos Determinar os padrões anatômicos (diâmetro e angulações) mais frequentes da aorta abdominal e de seus ramos e a influência do sexo e da idade dos pacientes sobre esses padrões. Métodos Foram avaliadas tomografias computadorizadas de abdome com contraste endovenoso de 157 pacientes. Foram aferidos calibre e angulação de artérias abdominais em indivíduos de ambos os sexos, agrupados em cinco faixas etárias: 20 a 30 anos, 31 a 40 anos, 41 a 50 anos, 51 a 60 anos e 61 a 70 anos. Foram analisadas 18 variáveis: seis ângulos de emergências arteriais, nove diâmetros arteriais, taxas de dilatação, sexo e faixa etária. Para a obtenção das medidas, utilizou-se o programa de computador RadiAnt 4.2.1 DICOM viewer (Medixant, Poznan, Polônia). Resultados Entre as 157 tomografias, 69 eram de homens e 88, de mulheres. Apresentaram diferença estatística (p < 0,05): ângulo de origem e diâmetro da artéria mesentérica superior; ângulo e diâmetro das artérias renais; diâmetro das artérias ilíacas comuns; diâmetro e taxa de dilatação em diversos segmentos da aorta, exceto na porção proximal ao tronco celíaco. Conclusões Os diâmetros da aorta (em diversos segmentos) e de seus ramos (exceto da artéria renal esquerda) aumentam progressivamente com o passar da idade em ambos os sexos e são maiores e possuem taxa de dilatação mais elevada em homens do que em mulheres da mesma faixa etária. Entre os sexos, o ângulo de emergência da artéria mesentérica superior foi maior em homens, exceto entre 20 e 30 anos; o ângulo de origem da artéria renal esquerda foi maior em mulheres entre 51 e 60 anos.