[Study on methods measuring mechanical properties of arterial wall by macroscopic indentation].

Accurately evaluating the local biomechanics of arterial wall is crucial for diagnosing and treating arterial diseases. Indentation measurement can be used to evaluate the local mechanical properties of the artery. However, the effects of the indenter's geometric structure and the analysis theory on measurement results remain uncertain. In this paper, four kinds of indenters were used to measure the pulmonary aorta, the proximal thoracic aorta and the distal thoracic aorta in pigs, and the arterial elastic modulus was calculated by Sneddon and Sirghi theory to explore the influence of the indenter geometry and analysis theory on the measured elastic modulus. The results showed that the arterial elastic modulus measured by cylindrical indenter was lower than that measured by spherical indenter. In addition, compared with the calculated results of Sirghi theory, the Sneddon theory, which does not take adhesion forces in account, resulted in slightly larger elastic modulus values. In conclusion, this study provides parametric support for effective measurement of arterial local mechanical properties by millimeter indentation technique.

Anatomical variations and embryological basis of arch of aorta and aortic valve.

Variations in the arch of the aorta and aortic valves among fetal, cadaveric, and post-mortem specimens present a spectrum of anatomical configurations, posing challenges in establishing a standard norm. While some variations hold surgical significance, many bear little functional consequence but provide insights into embryological origins. The aortic arch exhibits diverse branching patterns, including common trunks and different orders, relevant for endovascular surgeries. Meanwhile, malformations in the aortic valve, affecting the aorta, may lead to ischemia and cerebral infarction, warranting understanding of coexisting arch and valve anomalies to predict complications like aortic dissection. Studies in the Indian population mirror global variations, underscoring the need to explore embryological, clinical, and surgical implications for safer vascular surgeries involving the aortic arch and valves. The study's objectives included examining branching patterns, diameters, and distances between arch branches and exploring aortic valve variations. Employing a cross-sectional design, the study was conducted across Anatomy, Forensic Medicine, and Obstetrics and Gynecology departments. A sample of 100, comprising cadavers, fetuses, and postmortem specimens, were gathered. Specimens ranged from 14 weeks of intrauterine life to 85 years, with intact thoracic cages as inclusion criteria. Methodology involved dissection, specimen fixation, and macroscopic examination for variations and morphological parameters. Results showed aortic diameter increase with age, with significant gender differences. A statistically significant association between arch variations and anomalous valves was observed, suggesting mutual predictability. Individuals with valve anomalies should undergo comprehensive cardiology evaluation to avert complications like aortic dissection during endovascular surgeries. While atheromatous plaques were prevalent in younger groups, their frequency rose with age, necessitating vigilant vascular monitoring. Careful handling during surgeries is paramount, given potential adverse outcomes resulting from variations. Overall, the study underscores the importance of comprehensive anatomical understanding in clinical contexts, guiding effective management strategies and ensuring patient safety in vascular surgeries.

Morphology of the aortic arch branching pattern in raccoon dogs (Nyctereutes procyonoides, Gray, 1834).

BACKGROUND: Aortic arch (AA) branching patterns vary among different mammalian species. Most previous studies have focused on dogs, whereas those on raccoon dogs remain unexplored. OBJECTIVES: The objective of this study was to describe the AA branching pattern in raccoon dogs and compare their morphological features with those of other carnivores. METHODS: We prepared silicone cast specimens from a total of 36 raccoon dog carcasses via retrograde injection through the abdominal aorta. The brachiocephalic trunk (BCT) branching patterns were classified based on the relationship between the left and right common carotid arteries. The subclavian artery (SB) branching pattern was examined based on the order of the four major branches: the vertebral artery (VT), costocervical trunk (CCT), superficial cervical artery (SC), and internal thoracic artery (IT). RESULTS: In most cases (88.6%), the BCT branched off from the left common carotid artery and terminated in the right common carotid and right subclavian arteries. In the remaining cases (11.4%), the BCT formed a bicarotid trunk. The SB exhibited various branching patterns, with 26 observed types. Based on the branching order of the four major branches, we identified the main branching pattern, in which the VT branched first (98.6%), the CCT branched second (81.9%), the SC branched third (62.5%), and the IT branched fourth (52.8%). CONCLUSIONS: The AA branching pattern in raccoon dogs exhibited various branching patterns with both similarities and differences compared to other carnivores.

Variability in structure, morphology, and mechanical properties of the descending thoracic and infrarenal aorta around their circumference.

Aortic diseases, such as aneurysms, atherosclerosis, and dissections, demonstrate a preferential development and progression around the aortic circumference, resulting in a highly heterogeneous disease state around the circumference. Differences in the aorta's structural composition and mechanical properties may be partly responsible for this phenomenon. Our goal in this study was to analyze the mechanical and structural properties of the human aorta at its lateral, anterior, posterior, and medial quadrants in two regions prone to circumferentially inhomogeneous diseases, descending Thoracic Aorta (TA) and Infrarenal Aorta (IFR). Human aortas were obtained from 10 donors (64 ± 11 years) and dissected from their loose surrounding tissue. Mechanical properties were determined in all four quadrants of TA and IFR using planar biaxial testing and fitted to three common constitutive models. The structure of tissues was assessed using Movat Pentachrome stained histology slides. We observed that the anterior quadrant exhibited the greatest thickness, followed by the lateral region, in both the TA and IFR. In TA, the posterior wall appeared as the stiffest location in most samples, while in IFR, the anterior wall was the stiffest. We observed a higher glycosaminoglycans content in the lateral and posterior regions of the IFR. We found elastin density to be similar in TA lateral, anterior, and posterior quadrants, while in IFR, the anterior region demonstrated the highest elastin density. Despite significant variations between subjects, this study highlights the distinct morphometrical, mechanical, and structural properties between the quadrants of both TA and IFR.

Morphology of aortic arch branching patterns in the Eurasian Otter (Lutra lutra, Linnaeus, 1758).

In this study, we investigated the aortic arch (AA) branching pattern in the Eurasian otter (Lutra lutra). We performed arterial silicone casting of the AA of 18 Eurasian otters (8 males and 10 females). We analyzed the AA branching pattern at three levels: the AA, brachiocephalic trunk (BCT), and subclavian artery (SB), using different classification methods at each level. We introduced new criteria for classifying the SB branching pattern applicable for Eurasian otter and other carnivores based on the sequence of the four main branches: vertebral artery (VT), internal thoracic artery (IT), costocervical artery (CCT), and superficial cervical artery (SC). In all Eurasian otters, two major branches emerged directly from the AA, i.e., the BCT and left SB. The BCT branched off the left common carotid artery and terminated in the right common carotid artery and right SB in 17 of 18 Eurasian otters; the BCT formed a bicarotid artery in the remaining case. The SBs showed various branching patterns, with the main branching pattern involving branching to the VT and IT at the same position, followed by the CCT and SC. The SB branching pattern in the Eurasian otter differed from that in dogs in that the two first branching arteries were VT and IT, rather than VT and CCT. Here, we present the anatomical characteristics of the AA branching patterns in the Eurasian otter and new analysis methods applicable for comparative studies of other carnivores.

Effect of aging on the biaxial mechanical behavior of human descending thoracic aorta: Experiments and constitutive modeling considering collagen crosslinking.

Collagen crosslinking, an important contributor to the stiffness of soft tissues, was found to increase with aging in the aortic wall. Here we investigated the mechanical properties of human descending thoracic aorta with aging and the role of collagen crosslinking through a combined experimental and modeling approach. A total of 32 samples from 17 donors were collected and divided into three age groups: <40, 40-60 and > 60 years. Planar biaxial tensile tests were performed to characterize the anisotropic mechanical behavior of the aortic samples. A recently developed constitutive model incorporating collagen crosslinking into the two-fiber family model (Holzapfel and Ogden, 2020) was modified to accommodate biaxial deformation of the aorta, in which the extension and rotation kinematics of bonded fibers and crosslinks were decoupled. The mechanical testing results show that the aorta stiffens with aging with a more drastic change in the longitudinal direction, which results in altered aortic anisotropy. Our results demonstrate a good fitting capability of the constitutive model considering crosslinking for the biaxial aortic mechanics of all age groups. Furthermore, constitutive modeling results suggest an increased contribution of crosslinking and strain energy density to the biaxial stress-stretch behaviors with aging and point to excessive crosslinking as a prominent contributor to aortic stiffening.

Optimal guiding catheter position during advancement of the guiding catheter into the carotid artery from the aortic arch via transfemoral approach.

BACKGROUND: Guiding catheter (GC) advancement into the target carotid artery is a crucial step in neuroendovascular therapy. In difficult anatomies, alternative methods have been reported to overcome difficult carotid access for swift GC advancement. However, studies focusing on the positional relationship between the GC and inner catheter (IC) at the aortic arch are lacking. METHODS: We evaluated the impact of the positional relationship between the GC and IC on whether the GC position affects catheter support or system straightening. We retrospectively reviewed 89 patients who underwent neuroendovascular therapy. We assessed the time to carotid access across difficult arch anatomies. The GC position was divided into Position 1, descending aorta level; Position 2, aortic arch level; and Position 3, origin of the left common carotid artery or innominate artery. We also evaluated the GC support and straightening effects in an in vitro vascular model study. RESULTS: The coaxial catheter flexion angle at the aortic arch was significantly larger when the GC was set to Position 3 (p < 0.0001). A significantly shorter time to carotid access was observed with Positions 2 and 3 than with Position 1 in the difficult arch anatomy group. In the in vitro vascular model evaluation, the catheter support effect significantly increased as the GC position became closer to the IC tip (p < 0.0001) and straightening effect significantly increased as the GC moved to Position 2 from Position 1 (p < 0.0001). CONCLUSION: During GC advancement, the GC positional relationship changed the support of the coaxial system with system straightening. The optimal GC position, Position 3, facilitated swift GC advancement.

Morphology of the pattern of branching of the aortic arch (Arcus aortae) in Syrian hamsters (Mesocricetus auratus).

The branching patterns of the aortic arches of 28 adult male and female Syrian hamsters (SH) were thoroughly examined under a stereomicroscope for the first time by using latex injection and corrosion casting to determine their general arrangements and morphological variations as well as their differences and similarities to other rodents and rabbits. Three major arteries, namely, the brachiocephalic trunk (BC), left common carotid artery (CC) and left subclavian artery (SA), originating from the aortic arch (AR), were uniformly noted in SH. The BC was consistently divided into the right SA and the right CA. SA in SH normally releases the internal thoracic, deep cervical, dorsal scapular, vertebral, superficial cervical and supreme intercostal arteries. The costocervical trunk typically consisted of supreme intercostal and internal thoracic arteries and a common trunk for dorsal scapular and deep cervical arteries. To comprehend the comparative morphology of the pattern of branching of AR more completely, our results were compared with previous studies in rodents and rabbits. (1) The general morphology of the great arteries from AR in SH was similar to that in mole rats, rats, mice, porcupines, and gerbils but was essentially different from that in rabbits, guinea pigs, red squirrels, ground squirrels, pacas and chinchillas. (2) The typical pattern of the branching of the subclavian arteries in SH was similar to that in guinea pigs, rats, and rabbits but was different from that of the reported rodents regardless of the origins of the bronchoesophageal and internal thoracic arteries and the composition of the costocervical trunk.

Two cases of variations in inferior thyroid arterial pattern and their clinical implications.

Vascular variations are the most common ones in humans. Inferior thyroid artery arises from the thyrocervical trunk in 90.5%, from subclavian in 7.5%, and very rarely from the common carotid, aortic arch, brachiocephalic, internal thoracic, pericardiacophrenic, or vertebral. Thyroid ima artery is more common variety found in up to12.2% of the population. Two cadavers dissected in the anatomy department are presented with variations in the blood supply of the thyroid gland. The first case was a 61-year-old man with middle thymothyroid artery arising from the common carotid on the right side and inferior thyroid as a branch of the common carotid on the left. The second case was an 85-year-old female without inferior thyroid arteries bilaterally, replaced by thyroid ima arising from brachiocephalic artery. The awareness of such arterial pattern is crucial for the specialists in imaging and preoperative diagnosing and escaping eventual iatrogenic complications of thyroid gland.

Manejo híbrido del trauma de arco aórtico / Hybrid management of aortic arch trauma

El trauma aórtico es la segunda causa de muerte por trauma cerrado. Presentamos el caso de un paciente al que se le realizó un abordaje híbrido dadas las características, la localización y las particularidades anatómicas de la lesión, con excelentes resultados.Se trata de un paciente de 31 años que ingresó remitido con un cuadro de 15 días de evolución de un trauma contundente por la caída desde un parapente (desde 15 metros de altura). En la atención inicial se evidenció una fractura abierta del miembro inferior izquierdo manejada con tutor externo, hemotórax y neumotórax bilateral, manejados con toracostomía cerrada. Se tomaron imágenes según los protocolos de trauma, que evidenciaron lesión aórtica de grado III. Se decidió reparación híbrida: debranching desde la aorta ascendente hacia el tronco braquiocefálico y la arteria carótida común izquierda, con posterior reparación endovascular con endoprótesis aórtica para cobertura desde la zona cero a la zona cuatro de Ishimaru con sistema endovascular Zenith Cook dissection (Cook Medical Inc., Bloomington, Indiana, Estados Unidos). La evolución posterior fue satisfactoria y sin complicaciones.(AU)

Aortic trauma is the second cause of death due to blund trauma. We present a patient who underwent a hybrid approach given the characteristics, location, and anatomical characteristics of the lesion, with excellent results.A 31-year-old male patient was admitted with a 15-day of blunt trauma due to a fall from a paraglider (15 meters). Initial care revealed an open fracture of the left lower limb managed with an external tutor, hemothorax and bilateral pneumothorax, managed with a closed thoracostomy. Images were taken according to trauma protocols, showing grade III aortic injury. Hybrid repair was decided, debranching from the ascending aorta towards the brachiocephalic trunk and the left common carotid artery, with subsequent endovascular repair aortic endoprosthesis for coverage from zone zero to zone four of Ishimaru with Zenith Cook dissection endovascular system (cook Medical INC., Bloomington, In, USA), uncomplicated procedures.(AU)

The left-sided aortic arch variants: prevalence meta-analysis of imaging studies.

PURPOSE: To estimate the prevalence of the left-sided aortic arch (LSAA) variants, and the effect of possible moderators on variants' detection. METHODS: A systematic online literature search was conducted. The pooled prevalence with 95% confidence intervals was estimated for the typical and atypical branching patterns to compare the overall proportions of different variants. Meta-regression analyses were performed to investigate the effect of the subjects' gender and geographical region, and the multidetector computed tomography (MDCT) scanner's technology on the estimated prevalence. RESULTS: In total, 18,075 cases from 23 imaging studies were included and 33 different LSAA variants were detected. The estimated heterogeneity was statistically significant. Based on the estimated prevalence, approximately 77% of the population is expected to have the typical branching anatomy with sequence brachiocephalic trunk-left common carotid artery-left subclavian artery, and 23% variant branching patterns. Approximately 71%, 23%, 2%, and 0.1% of the atypical populations are expected to have two, four, three, and five emerging branches, respectively. The meta-regression analyses showed that the number of detector rows of the MDCT scanner, and the subjects' geographical region are statistically significant moderators of the estimated prevalence. CONCLUSION: The current findings indicate that the prevalence of the LSAA variant branching anatomy is significantly affected by the subjects' geographical region and the MDCT scanner's technological improvement, with the advanced scanners to facilitate the detection of the aortic arch variants. However, due to the heterogeneity among studies, further research is required.

Greater Curvature, Centerline or Straightened Centerline Length - Which length is Most Accurate for Preprocedural Planning in Thoracic Endovascular Aortic Repair?

BACKGROUND: Automated centerline (CL) measurements have been conventionally used for stent-graft length estimation during thoracic endovascular aortic repair (TEVAR). The purpose of this study was to assess the accuracy of greater curvature length (GL), semiautomated CL and straightened centerline length (SCL) for preprocedural planning in TEVAR. METHODS: Immediate postprocedural CT Angiographies of 30 patients (22 males, age-49.2 ± 10.1years) who underwent TEVAR between 2015 and 2017 were retrospectively analyzed. CL, GL, SCL and the straightline length(SL) were measured between proximal and distal ends of the stent-graft and results were compared with the true length of the stent-graft (TL). Tortuosity index (TI = CL/SL) was calculated. RESULTS: GL (17.92 ± 4.78 cm) was the closest in predicting the TL (17.75 ± 4.29 cm) (P = 0.414) overall, as well as in both dissection and aneurysm subgroups (P= 0.9). There was a significant difference between CL (16.67 ± 4.07 cm) and TL (P< 0.0001) as well as between SCL (16.86 ± 4.16 cm) and TL (P= 0.001). These differences were greater in dissection subgroup than in the aneurysm group (P< 0.0001 and P= 0.03 for TL-CL and TL-SCL, respectively). The extent of mismatch between GL or CL and TL did not correlate with tortuosity, but the difference between TL and SCL had a significant positive correlation with tortuosity (r = 0.375, P= 0.04). TL-GL had a negative linear correlation with the stent-graft length (TL) in the dissection group (r = 0.50, P= 0.03). CONCLUSIONS: The greater curvature length predicts the actual total length of the deployed stent-graft more accurately than centerline or straightened centerline lengths. Hence, it should be used in planning for the length of stent-graft required for TEVAR.

A Ten-year Single-center Surgical Experience With Symptomatic Complete Vascular Rings.

BACKGROUND: Limited data exist on the management of complete vascular rings (CVR) in adults. We reviewed our institution's surgical experience in the management of these patients. METHODS: Between 2010 and 2019, all adult patients that underwent a thoracotomy for a CVR repair were identified. We performed a retrospective medical record review of these patients to characterize their demographics and outcomes. RESULTS: Among the 5 patients identified (3 females, 2 males; Mean age 50 ± 9 years), anatomic variants were right arch and Kommerell diverticulum (KD) in 3 (60%) and double aortic arch in 2 (40%) patients. Indications for operation included dysphagia in 4 (80%), respiratory symptoms in 3 (60%) and aneurysmal KD in 1 (20%) patient. Two right aortic arch exclusion, 1 ligamentum arteriosum (LA) division, 1 LA division combined with a KD resection and 2 aortic reconstructions with interposition Dacron graft under partial cardiopulmonary bypass, were performed. Two carotid-subclavian artery transpositions prior to the thoracotomy were done. The postoperative length of stay was 10.0 (IQR 7.3-14.8) days. One reoperation for chylothorax and 1 for symptoms recurrence were performed for the same patient. Over a follow-up period of 1.4 (IQR 0.4-7.0) years, no mortality or major postoperative complications occurred. At their last follow-up visit, all patients reported no related remaining symptoms, except for persisting mild asthma in 1 patient. CONCLUSIONS: Open repair of CVR in adults can be performed safely with low complication rate. Symptoms improved in all patients after definitive repair.

Morphology of the left subclavian artery: implications for single-branched endovascular aortic arch repair.

OBJECTIVES: Our goal was to evaluate the morphology of the aortic arch, focusing on the left subclavian artery (LSA), and to anticipate implications for single-branched endovascular aortic arch repair. METHODS: We performed a morphological analysis of computed tomography angiography scans of 322 patients between January 2002 and December 2018. Arch type and distance between arch vessels on the convexity were evaluated. We defined 3 morphological types: U-type distance between the left common carotid artery (LCCA) and LSA offspring >10 mm; V-type distance between the LCCA and LSA offspring <10 mm and W-type isolated left vertebral artery offspring from the aortic arch. RESULTS: Most patients presented a type III arch [50% (n = 161)]. The median distance from the brachiocephalic trunk offspring to the LCCA offspring measured 2.5 mm (2.0-3.0 mm) and that between the LCCA offspring and the LSA offspring was 6.5 mm (4.0-11.0 mm). We observed no significant difference based on the morphological type (V versus U versus W) in the brachiocephalic trunk-LCCA distance, but there were significant differences in the LCCA-LSA distance between types V and U (P < 0.001) and between types V and W (P < 0.001). Interestingly, we found no significant difference in the LCCA-LSA distance between types U and W. We noted a significant difference in the median diameter of the LSA according to U, V and W types: V type versus U type, 12.5 vs 13.5 mm (P = 0.033) as well as U type versus W type, 13.5 vs 10.5 mm (P < 0.001) and V type versus W type, 12.5 vs 10.5 mm (P < 0.002). The distances between the LSA offspring and left vertebral artery offspring between types U and V did not differ significantly. CONCLUSIONS: Our categorization of the U, V and W types of the LSA can help us anticipate shapes and distances and thereby function as an initial evaluation tool for predicting single branched endovascular aortic arch repair involving the LSA.

Deep learning enables genetic analysis of the human thoracic aorta.

Enlargement or aneurysm of the aorta predisposes to dissection, an important cause of sudden death. We trained a deep learning model to evaluate the dimensions of the ascending and descending thoracic aorta in 4.6 million cardiac magnetic resonance images from the UK Biobank. We then conducted genome-wide association studies in 39,688 individuals, identifying 82 loci associated with ascending and 47 with descending thoracic aortic diameter, of which 14 loci overlapped. Transcriptome-wide analyses, rare-variant burden tests and human aortic single nucleus RNA sequencing prioritized genes including SVIL, which was strongly associated with descending aortic diameter. A polygenic score for ascending aortic diameter was associated with thoracic aortic aneurysm in 385,621 UK Biobank participants (hazard ratio = 1.43 per s.d., confidence interval 1.32-1.54, P = 3.3 × 10-20). Our results illustrate the potential for rapidly defining quantitative traits with deep learning, an approach that can be broadly applied to biomedical images.

Descending Aorta Diameters as Predictor of Late Adverse Outcomes in Patients with Uncomplicated Type B Aortic Dissection: A Systematic Review and Meta-Analysis.

BACKGROUND: A subset of patients with uncomplicated type B aortic dissection (uTBAD) has been shown to possess higher risk of experiencing late adverse outcomes. Therefore, we conducted an analysis to investigate the role of descending aorta diameters, including total descending aorta diameter and false lumen diameter, as predictor of late adverse outcomes in patients with uTBAD. METHODS: A systematic search was performed through Pubmed, ClinicalKey, ScienceDirect, and Cochrane Library to identify relevant studies. Our primary outcome was the composite late adverse events following their first episode of hospitalization. All meta-analyses were performed using Review Manager version 5.4. RESULTS: A total of 2,339 (male 68.8%) patients from a total of 15 cohorts were included in our analysis. During follow-up period, there were 655 (27.3%) and 149 (6.3%) cases of late adverse events and mortality, respectively. Patients with higher initial descending aorta diameter were at higher risk of developing late adverse events (RR 2.99 [2.60, 3.44]; P < 0.001) and mortality (RR 3.15 [2.34, 4.25]; P <0.001) throughout follow-up period. Maximum false lumen diameter at the initial presentation seemed to significantly be associated with late adverse events (RR 1.87 [1.46, 2.39]; P <0.001) but not with mortality (RR 2.55 [0.81-8.00; P = 0.11). CONCLUSION: Descending aorta diameters, particularly maximum initial descending aorta diameter, is a good and helpful predictor of late adverse outcomes in patients with uTBAD.

Determination of Optimal and Safest Proximal Sealing Length During Thoracic Endovascular Aortic Repair.

OBJECTIVE: To determine the optimal and safest proximal sealing length (PSL) during thoracic endovascular aortic repair (TEVAR), depending on anatomical aortic arch types and proximal landing zones (LZs). METHODS: This was a single centre retrospective observational study of consecutive TEVAR patients (2008-2020). All aortic pathologies requiring Ishimaru landing zone (LZ) 0 - 3 were included; results were stratified by aortic arch type. The PSL was measured as the length of complete aortic wall to endograft apposition at the level of the proximal neck. The primary endpoint was proximal failure (type 1A endoleak, endograft migration, or re-intervention requiring proximal graft extension). Freedom from proximal failure was estimated with Kaplan-Meier curves. An "optimal" sealing length (PSL cutoff maximising sensitivity + specificity for proximal failure) and "safest length" (PSL cutoff determining ≥ 90% sensitivity) were identified using receiver operating characteristic curve analysis. RESULTS: One hundred and forty patients received TEVAR; mean ± standard deviation PSL was 29 ± 9 mm. Freedom from proximal endograft failure at five years (median 31 months) was 82.4% (95% confidence interval [CI] 72 - 95); the shorter the PSL, the greater was the risk of failure (hazard ratio 0.90, 95% CI 0.84 - 0.97; p = .004). Overall optimal and safest PSL were 25 mm (sensitivity 78%, specificity 66%) and 30 mm (sensitivity 92%, specificity 30%), respectively. In type I arch, the optimal PSL was 22 mm (sensitivity 50%, specificity 87%). In type II, the optimal PSL was 25 mm (sensitivity 89%, specificity 59%) overall and 27 mm for type II/LZ 2 - 3 (sensitivity 31%, specificity 68%). For type III, the optimal PSL was 27 mm (sensitivity 80%, specificity 87%); the safest was 30 mm (sensitivity 100%, specificity 61%) In type III/LZ 2 - 3, the optimal PSL was 27 mm (sensitivity 31%, specificity 68%) and safest was 30 mm (sensitivity 100%, specificity 55%). CONCLUSION: A 20 mm PSL may be acceptable only for type I arches. For types II/III, that represent the majority of cases, a 25 - 30 mm PSL may be required for a safe and durable TEVAR.

The relation between aortic arch branching types and the location of large vessel occlusion in cardioembolic stroke.

Cardiac embolism is the leading etiology of ischemic strokes. There are arguments about the left-right propensity of cardioembolic strokes.This study aimed to reveal the relationship between the different aortic arch types and the location of large vessel occlusion (LVO) in cardioembolic stroke.We retrospectively identified all patients with acute ischemic stroke admitted to our comprehensive stroke center who had medium- to high-risk cardioembolicsources according to the TOAST classification.Only those with LVO and available images of the aortic arch were included. Patients were classified into 3 groups according to the aortic arch types: Type I (n = 44), Type II (n = 105), Type III (n = 36).The thrombus was divided into large thrombus or small thrombus based on the location of LVO.Overall, left-sided strokes (50.8%) were almost equal to right-sided (49.2%). There was a growing tendency for the percentage of left-sided infarcts with advancement of the aortic arch types either in the total cases or in the atrial fibrillation cases, with no statistical difference between the 3 aortic arch types.In type III aortic arch, left-sided strokes (69.0%) were twice than right-sided (31%) in large thrombus (P < 0.05), while right-sided strokes (85.7%) were more common than left-sided (14.3%) in small thrombus (P < 0.05).Conversely, in type Ⅰ and II aortic arches, left-sided strokes were more common than right-sided in small thrombus, while right-sided strokes were more common than left-sided in large thrombus (P < 0.05). The left-right propensity of cardioembolic stroke is related to the proximity of clot lodging in different aortic arch types.

From Uniaxial Testing of Isolated Layers to a Tri-Layered Arterial Wall: A Novel Constitutive Modelling Framework.

Mechanical testing and constitutive modelling of isolated arterial layers yields insight into the individual layers' mechanical properties, but per se fails to recapitulate the in vivo loading state, neglecting layer-specific residual stresses. The aim of this study was to develop a testing/modelling framework that integrates layer-specific uniaxial testing data into a three-layered model of the arterial wall, thereby enabling study of layer-specific mechanics under realistic (patho)physiological conditions. Circumferentially and axially oriented strips of pig thoracic aortas (n = 10) were tested uniaxially. Individual arterial layers were then isolated from the wall, tested, and their mechanical behaviour modelled using a hyperelastic strain energy function. Subsequently, the three layers were computationally assembled into a single flat-walled sample, deformed into a cylindrical vessel, and subjected to physiological tension-inflation. At the in vivo axial stretch of 1.10 ± 0.03, average circumferential wall stress was 75 ± 9 kPa at 100 mmHg, which almost doubled to 138 ± 15 kPa at 160 mmHg. A ~ 200% stiffening of the adventitia over the 60 mmHg pressure increase shifted layer-specific load-bearing from the media (65 ± 10% → 61 ± 14%) to the adventitia (28 ± 9% → 32 ± 14%). Our approach provides valuable insight into the (patho)physiological mechanical roles of individual arterial layers at different loading states, and can be implemented conveniently using simple, inexpensive and widely available uniaxial testing equipment.

Morphometric study on the 12th thoracic vertebrae which is most frequently exposed to trauma and the closest vertebra to thoracic aorta.

BACKGROUND: To describe gender-related differences in the length of the left chord and pedicle at the level of 12th thoracic vertebrae and appropriate length of the screw to be applied so as to decrease the perforation risk of anterior cortex of the corpus and preventable injury of major vascular vessels. METHODS: Axial bone window computed tomography images of T12 vertebral pedicles of 60 patients (30 males and 30 females, age >25 years) without any sign of spinal trauma were obtained and morphometric data were analyzed. RESULTS: Mean ages of the female (n=30) and male (n=30) patients were 32.17±4.24 and 31.70±3.60 years, respectively. The left chord lengths of T12 of the male (38.17±2.54 mm) and female (36.62±2.27 mm) patients were compared and a statistically significant difference was found between these two measurements (p=0.016). A statistically significant difference between the length of the left chord (37.40±2.51) (range, 32-44 mm) and age (31.93±3.91) (range, 25-40 years) and also a moderate degree of correlation were observed (p=0.002), (r=0.401). A statistically significant difference and a moderate degree of correlation were found between the lengths of the left chords (37.40±2.51; range, 32-44 mm) and the left pedicles (12.12±1.34; range, 10.0-15.80 mm) (p=0.001), (r=0.577). CONCLUSION: Significant differences and correlations exist between the left pedicle and the left chord in male and female patients and patients with different ages. The data obtained can be used as a guide to determine the implant size and intraoperative management of T12 vertebral pedicle.