Thoracic Aortic Aneurysm

Projection of global burden and risk factors for aortic aneurysm - timely warning for greater emphasis on managing blood pressure

RATIONALE

Aortic aneurysm (AA) is a serious condition that largely increases the risk of aortic dissection and sudden death. Exploring the global burden of disease and changes in risk factors for AA is essential for public health policy development.

OBJECTIVE

To project the death burden from AA and its attributable risk factors in the following decade based on the epidemiological data over the past 30 years.

METHODS AND RESULTS

We analysed the death burden of AA and trends of four risk factors from 1990-2019 using the updated 2019 Global Burden of Disease study database by Joinpoint regression analysis. Furthermore, we project the AA-related death burden for the next decade using the Bayesian age-period-cohort model. This study discovered that the global burden of death attributable to AA began to increase after decreasing for two decades. This upward trend will continue in the subsequent decade (average annual percent change: 0.318%, 95% CI: 0.288 to 0.348). Meanwhile, the disease burdens in all economic regions except high-middle socio-demographic index (SDI) regions will continuously increase in the next decade, with the fastest acceleration in the low-middle SDI region (average annual percent change: 1.183%, 95% CI: 1.166 to 1.200). Notably, high systolic blood pressure will surpass the contribution of smoking to become the most important risk factor for mortality due to AA.

CONCLUSION

This study discovered a rebounding trend in the aortic aneurysm-related death burden globally. High systolic blood pressure will be the top risk factor attributed to death from AA. Therefore, it should be considered as the first-degree risk factor in the guidance of AA management and criteria for population-based screening programs.Key messagesThe death burden of aortic aneurysms is beginning to rebound globally, and the trend will continue for the next decade.High systolic blood pressure will replace smoking as the most important risk factor associated with aortic aneurysm death.

Association of Collagen, Elastin, Glycosaminoglycans, and Macrophages With Tissue Ultimate Material Strength and Stretch in Human Thoracic Aortic Aneurysms: A Uniaxial Tension Study

Fiber structures and pathological features, e.g., inflammation and glycosaminoglycan (GAG) deposition, are the primary determinants of aortic mechanical properties which are associated with the development of an aneurysm. This study is designed to quantify the association of tissue ultimate strength and extensibility with the structural percentage of different components, in particular, GAG, and local fiber orientation. Thoracic aortic aneurysm (TAA) tissues from eight patients were collected. Ninety-six tissue strips of thickened intima, media, and adventitia were prepared for uni-extension tests and histopathological examination. Area ratios of collagen, elastin, macrophage and GAG, and collagen fiber dispersion were quantified. Collagen, elastin, and GAG were layer-dependent and the inflammatory burden in all layers was low. The local GAG ratio was negatively associated with the collagen ratio (r2 = 0.173, p < 0.05), but positively with elastin (r2 = 0.037, p < 0.05). Higher GAG deposition resulted in larger local collagen fiber dispersion in the media and adventitia, but not in the intima. The ultimate stretch in both axial and circumferential directions was exclusively associated with elastin ratio (axial: r2 = 0.186, p = 0.04; circumferential: r2 = 0.175, p = 0.04). Multivariate analysis showed that collagen and GAG contents were both associated with ultimate strength in the circumferential direction, but not with the axial direction (collagen: slope = 27.3, GAG: slope = -18.4, r2 = 0.438, p = 0.002). GAG may play important roles in TAA material strength. Their deposition was found to be associated positively with the local collagen fiber dispersion and negatively with ultimate strength in the circumferential direction.

LncRNA AK131850 is downregulated in thoracic aortic aneurysm and negatively affects the levels of TGF-β1 in aortic smooth muscle cells

This study aimed to investigate the role of lncRNA AK131850 in thoracic aortic aneurysm (TAA). We found that AK131850 was downregulated, while TGF-β1 was upregulated in aortic media specimen of thoracic aortic aneurysm (TAA) patients. In addition, AK131850 and TGF-β1 inversely correlated. Altered expression levels of AK131850 and TGF-β1 distinguished TAA patients from healthy controls. In human aortic smooth muscle cells (HAOSMC), AK131850 overexpression led to downregulated, while AK131850 siRNA silencing led to upregulated TGF-β1. AK131850 overexpression resulted in promoted, while siRNA silencing led to inhibited proliferation of HAOSMC. Therefore, AK131850 is downregulated in thoracic aortic aneurysm and negatively affects the levels of TGF-β1 in aortic smooth muscle cells.

NADPH Oxidases in Aortic Aneurysms

Abdominal aortic aneurysms (AAAs) are a progressive dilation of the infrarenal aorta and are characterized by inflammatory cell infiltration, smooth muscle cell migration and proliferation, and degradation of the extracellular matrix. Oxidative stress and the production of reactive oxygen species (ROS) have been shown to play roles in inflammatory cell infiltration, and smooth muscle cell migration and apoptosis in AAAs. In this review, we discuss the principles of nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase/NOX) signaling and activation. We also discuss the effects of some of the major mediators of NOX signaling in AAAs. Separately, we also discuss the influence of genetic or pharmacologic inhibitors of NADPH oxidases on experimental pre-clinical AAAs. Experimental evidence suggests that NADPH oxidases may be a promising future therapeutic target for developing pharmacologic treatment strategies for halting AAA progression or rupture prevention in the management of clinical AAAs.

A canine model of aortic arch aneurysm created with autologous pericardium

Background

To establish a canine model of aortic arch aneurysm that is suitable for research on new devices and techniques applied to the aortic arch.

Materials and methods

Fifteen mongrel dogs underwent surgery. The autologous pericardial patch was sewn on the aortotomy site in the anterior wall of the aortic arch. The animals were followed up for 3 months postoperatively. Computed tomography angiography was used to visualize and measure the aneurysm model. Hematoxylin and eosin staining was used to observe the histological characteristics of the aneurysm model. Changes in aneurysm diameter over time were analyzed using analysis of variance.

Results

One dog died of hemorrhage during surgery. Fourteen dogs survived the surgical procedure. Two of them died on the first postoperative day because of ruptures at the suturing margin. The diameter of the aneurysm model was twice as large as that of the aortic arch. There was no significant change in the maximum diameter of the aneurysm model during the follow-up period.

Conclusions

We established a controllable and stable aortic arch aneurysm model created with an autologous pericardium patch. The aneurysm model can be used to research endoleaks after thoracic endovascular aortic repair and new endovascular techniques can be applied to the aortic arch.

Numerical investigation of different viscosity models on pulsatile blood flow of thoracic aortic aneurysm (TAA) in a patient-specific model

Aortic aneurysm is one of the most common aortic diseases that can lead to unfortunate consequences. Numerical simulations have an important role in the prediction of the aftereffects of vascular diseases including aneurysm. In this research, numerical simulation of pulsatile blood flow is performed for a 3-dimensional patient-specific model of a thoracic aortic aneurysm (TAA). Since the choice of blood viscosity model may have a significant impact on the simulation results, the effects of four non-Newtonian models of blood viscosity namely Carreau, Casson, Herschel-Bulkley, power low, and the Newtonian model on the wall shear stress (WSS) distribution, shear rate, and oscillatory shear index (OSI) have been analyzed. Simulation results showed that all the non-Newtonian and Newtonian models generally, predict similar patterns for blood flow and shear rate. At high flow rates in the cardiac cycle, the WSS value for all the models are similar to each other except for the power-law model due to the shear thinning behavior. All models predict high values of OSI on the inner wall of the ascending aorta and broad areas of the inner wall of the aneurysm sac. However, the Newtonian model predicts the OSI less than the non-Newtonian models in some areas of the aneurysm sac. Results indicated that the Newtonian model generally can predict the hemodynamic parameters of the blood flow similar to the non-Newtonian but for more precise analysis and to predict the regions prone to rupture and atherosclerosis, choosing a proper non-Newtonian model is recommended.

Die Etablierung eines neuen Forschungskonzepts an einem universitären Standort

Neben der klinischen Tätigkeit haben an einem universitären Standort Forschung und Lehre einen großen Stellenwert. Durch die Etablierung eines neuen Forschungslabors an der Universitätsklinik für Gefäßchirurgie der Medizinischen Universität Innsbruck wurden die infrastrukturellen Voraussetzungen zur Gestaltung eines neuen Forschungsschwerpunkts geschaffen. Die Kooperation mit nationalen und internationalen Partnern war für diesen Prozess essenziell. Nicht nur in der Planung und Ausstattung der Räumlichkeiten, sondern auch in der Entwicklung von Studienprotokollen und zur kritischen Diskussion von Ergebnissen ist der Aufbau eines Netzwerkes von großer Bedeutung. Durch die Etablierung der experimentellen Gefäßchirurgie Innsbruck ist nun die Realisierung von Projekten der Grundlagenforschung und der translationalen Forschung an diesem universitären Standort möglich. Zudem spielt die Lehrforschung eine immer größere Rolle, insbesondere um die Ausbildungsstruktur möglichst praxisnah zu gestalten, Nachwuchs anzuwerben und die immer komplexer werdenden Techniken auch praxisnah zu vermitteln.

Toward standard abbreviations and acronyms for use in articles on aortic disease

Objectives

Academic medical literature is fraught with complex article-specific acronyms and abbreviations that can impair communication and make reading arduous. Our goal is to ease frustration with bespoke, inconsistent, and variable sets of abbreviations that currently exist for common aorta-related terminology (eg, anatomy, imaging, disease, and therapy). We hope to ease reading and improve communication in the aortic sphere of cardiovascular literature.

Methods

We reviewed a total of 205 published references related to aortic disease, including a systematic review of aorta-related articles in the Journal of Thoracic and Cardiovascular Surgery from the years 2020 and 2021. The array of variable definitions, abbreviations, and acronyms encountered in different papers that refer to the same terminology was striking, revealing that there were few standardized abbreviations in the aortic literature. We cataloged these terms, their associated abbreviations, and their frequency of use, and compiled a list of proposed standard abbreviations for commonly used terms that could be implemented uniformly in articles written about aortic diseases.

Results

We present suggested acronyms and abbreviations for common terminology related to the aorta. It is anticipated that this standard list will evolve over time as the literature and technology of the field grows and develops.

Conclusions

A proposed standard set of acronyms and abbreviations for aorta-related terminology is provided that, if found useful, could be implemented broadly in the aortic literature.

Can We Better Differentiate Type A Dissections: Evaluating the Role of Aortic Ratios

OBJECTIVES

Type A aortic dissection (ATAAD) is hypothesised as a progression of aneurysmal dilation, but 60% of patients in the International Registry of Acute Aortic Dissection (iRAD) registry had a maximum aortic diameter (MAD)<55 mm. We aim to demonstrate that size ratios and aortic wall stress, assessed using a simplified markers, are unique to aortic patients who have had adverse events (ATAAD) compared to those who have not (thoracic aortic aneurysm [TAA]).

METHODS

A retrospective cohort analysis of patients who underwent aortic intervention at Waikato Hospital, New Zealand between 2015-2020, comparing dissection (ATAAD) to TAA patients. MAD; ratio of MAD to standardised-points within the aorta; and MAD-to-height collected from computed tomography (CT)-scans of all patients was undertaken. Receiver operating characteristic (ROC)-analysis to determine cut-off point for each marker was undertaken together with multivariable logistic regression comparing both cohorts, cross-validated by propensity-score matched analysis.

RESULTS

Cohort of 215 patients, 78 (36.3%) ATAAD and 137 (63.7%) TAA; median age at intervention 63.3 years, 52 (24.2%) females, both cohorts matched for size. Using the entire cohort, the MAD: sinus of Valsalva (SoV) ratio>1.06 (cut-off value) had 4.5-times greater association with ATAAD (95%CI 1.46-13.8) and a 0.1-unit increased conferred 1.45-times greater association with ATAAD (95%CI 1.00-2.08). MAD>55 mm only seen in 33.3% of ATAAD (n=26/78), and not associated with ATAAD (OR 1.88, 95%CI 0.64-5.51). Compared to MAD, MAD:SoV ratio had greater sensitivity (33% vs 73%), lower number-needed-to-treat (17.9 vs 2.7) and superior discrimination (area under the curve [AUC] 0.54 vs 0.71). Findings were consistent with propensity score matched analysis.

CONCLUSIONS

MAD:SoV ratio significantly correlates with ATAAD (4.5 times), with superior sensitivity, discrimination, and attributable-risk-percentage compared to MAD alone.

Genetic screening in heritable thoracic aortic disease—rationale, potentials and pitfalls

Thoracic aortic aneurysms are silent yet deadly clinical entities which may elude detection until an acutely life-threatening aortic dissection or rupture occurs. Approximately 20% of patients with thoracic aortic aneurysms or dissection have a positive family history, indicating a strong genetic component to the aetiology. Genetic screening in such hereditary thoracic aortic disease (HTAD) may thus be beneficial in detecting causative genetic mutations in affected patients, identifying asymptomatic family members who may be at risk, and in guiding the optimal timing of preventative surgery in those with confirmed genetic aortopathy. Genetic screening can facilitate personalised aortic care tailored to an individual's specific genetic abnormality, with the aim of mitigating the significant morbidity burden and premature mortality associated with HTAD. This review examines the rationale for genetic screening in HTAD, its potential applications, current limitations and potential future directions.

The prevalence of thoracic aorta aneurysm as an important cardiovascular disease in the general population

BACKGROUND

The aorta is the largest and main artery in the body. The enlargement of the aortic diameter known as ectasia results in aneurysm. Thoracic aorta aneurysm can involve one or more segments of the aorta. Non-invasive imaging techniques play an important role in identifying patients, estimating maximal aneurysm diameter, following up patients, and detecting complications. So, this study was performed to estimate the prevalence of ascending thoracic aorta aneurysm in the general population of Iran.

METHODS

People with an abnormal aortic size (˃ 36 mm) were enrolled and subjected to diagnostic tests, and related risk factors were assessed.

RESULT

Of the 3400 people examined, 410 (12%) had abnormal aorta sizes, and 42 (1.2%) had ascending aorta aneurysm. Out of the 410 patients with elevated aorta size, 235 (57%) were males, and 175 (43%) were females. Overall, 229 patients (56%) had hypertension, and 255 (62%) were over 60 years old.

CONCLUSION

In this study, we showed that the prevalence of ascending aorta aneurysm in the general population of Iran was about 1.2%. Ascending aorta aneurysm is a threatening pathology of the aorta. The high prevalence of hypertension may explain the high incidence of aneurysm in our studied population. Therefore, it is necessary to implement an accurate screening plan to identify patients with hypertension and provide appropriate treatment and adequate follow up to patients. Patients with ascending aorta aneurysm are also recommended to modify their lifestyles.

A rare case of thoracic-abdominal aortic aneurysm in conjunction with bilateral superficial femoral artery occlusion, documented with computed tomography angiography

Aneurysms represent bulging of the weakened blood vessel area, as a result of cystic medial degeneration. Aneurysms chance of rupturing increases over time, resulting in bleeding and death. Therefore, patients with aortic aneurysms require frequent monitoring with magnetic resonance and computed tomography angiography, as well as undergoing open repair surgery and endovascular aneurysm repair.

We present a case of ruptured thoracic aortic aneurysm in conjunction with bilateral superficial femoral occlusion, as incidental findings in Covid-19 positive patient.

The patient, a 62-years-old female, presented with cough, shortness of breath, fever and leg claudication. Doppler ultrasonography of the lower limbs was conducted to rule out thromboembolism, revealing bilateral superficial femoral arteries occlusion. The patient was administered high doses of parenteral anticoagulants.

Hemoptysis ensued, prompting an MSCT scan, that showed right pleural effusion, atelectasis, and right active perihilar infiltrates with inter-lobar pleurisy. Due to inflammatory changes on the lung parenchyma, the patient got tested for Sars-Cov-2, and resulted positive.

Contrast-enhanced MSCT also revealed thoracic-abdominal aortic aneurysm with its highest diameter measuring 10 cm, and massive per-aortal thrombus and/or hematoma of 5 cm, which was further ruptured and patient died untreated in the fourth day of hospitalization.

Questions arise whether Covid-19 was the primary cause of bilateral superficial femoral artery occlusion and whether high doses of parenteral anticoagulants were the primary cause of thoracic aortic aneurysm rupture.

Thus, a careful balance must be made between the detrimental and protective contributions of anticoagulants in the patients presenting with Covid-19 and thoracic-abdominal aortic aneurysm.

Aortic gene dictionary in the precision medicine era—update from the Aortic Institute at Yale New Haven

This paper reviews the current understanding of the inherited, genetic nature of thoracic aortic aneurysm and dissection (TAAD), as well as the practice of genetic testing for thoracic aortic disease at the Aortic Institute at Yale-New Haven Hospital.

Computational Study of Abdominal Aortic Aneurysms with Severely Angulated Neck Based on Transient Hemodynamics Using an Idealized Model

An abdominal aortic aneurysm (AAA) is an enlargement of the abdominal aorta that can become a life-threatening disease. The pulsatile blood flow exhibits intricate laminar patterns in the abdominal portion of the human aorta under normal resting conditions, whereas secondary flows are caused by adjacent branches and abnormal vessel geometries. If a pathological disorder (e.g., aneurysm) alters the structural composition of the artery wall, the flow dynamics become more complex. In this study, we analyzed the hemodynamics of pulsatile blood flow in three-dimensional AAA models. Computational predictions of hemodynamic changes were performed considering idealized models for four severe proximal neck angulations of symmetric aneurysms assuming conditions of laminar flow and a rigid artery wall. The predictions were based on computational fluid dynamics throughout the cardiac cycle. Postprocessing was used to visualize the numerical findings. The hemodynamic changes in factors such as velocity, flow streamline, pressure, and wall shear stress were obtained and visualized. The resulting blood flow through the severely angulated proximal neck of the abdominal aorta caused strong turbulence and asymmetric flow inside the aneurysm sac, leading to blood recirculation, especially during diastole. The simulation results showed the formation of regions with high and low wall shear stress, turbulent flow, and recirculation in the aneurysm sac depending on the angulation, which could have led to aortic wall weakness.

[Role of imaging modalities in the choice of treatment strategy for mega aorta syndrome]

The authors report a 76-year-old female with mega-aorta syndrome that was asymptomatic for a long time. The first symptoms appeared after ascending aorta enlargement up to 81 mm and compression of superior vena cava. The patient underwent frozen elephant trunk procedure. The authors demonstrate the possibilities of assessing the aortic strain by ECG-synchronized CT angiography and 2D transesophageal ultrasound with speckle tracking. Potential role of these methods in determining the type of aortic reconstruction is discussed.

Genetics of Heritable Thoracic Aortic Disease

Genetic testing plays an increasing diagnostic and prognostic role in the management of patients with heritable thoracic aortic disease (HTAD). The identification of a specific variant can establish or confirm the diagnosis of syndromic HTAD, dictate extensive evaluation of the arterial tree in HTAD with known distal vasculature involvement and justify closer follow-up and earlier surgical intervention in HTAD with high risk of dissection of minimal or normal aortic size. Evolving phenotype–genotype correlations lead us towards more precise and individualized management and treatment of patients with HTAD. In this review, we present the latest evidence regarding the role of genetics in patients with HTAD.

Huge Thoracic Aortic Aneurysm Presenting with Jaundice: A Case Report

Introduction

Thoracic aortic aneurysms (TAA) are encountered frequently in the emergency department with an obscure presentation. Most of these aneurysms are incidentally discovered while doing routine imaging studies. This report describes a case of unusual presentation of TAAs.

Case Presentation

A 37-year-old male presented to the emergency department with jaundice, shortness of breath, abdominal swelling, and lower limb edema, which worsened during the previous month. The patient was worked up and diagnosed with an ascending aortic aneurysm measuring 6.9 cm associated with severe aortic insufficiency and heart failure.

Conclusion

TAA is a life-threatening condition with indistinct signs and symptoms. A high index of suspicion and early implementation of radiological studies are prerequisites to reach a diagnosis.

Ascending aorta curvature and flow displacement are associated with accelerated aortic growth at long-term follow-up: A MRI study in Marfan and thoracic aortic aneurysm patients

Background

Aortic aneurysm formation is associated with increased risk of aortic dissection. Current diagnostic strategies are focused on diameter growth, the predictive value of aortic morphology and function remains underinvestigated. We aimed to assess the long-term prognostic value of ascending aorta (AA) curvature radius, regional pulse wave velocity (PWV) and flow displacement (FD) on aortic dilatation/elongation and evaluated adverse outcomes (proximal aortic surgery, dissection/rupture, death) in Marfan and non-syndromic thoracic aortic aneurysm (NTAA) patients.

Methods

Long-term magnetic resonance imaging (MRI) and clinical follow-up of two previous studies consisting of 21 Marfan and 40 NTAA patients were collected. Baseline regional PWV, AA curvature radius and normalized FD were assessed as well as diameter and length growth rate at follow-up. Multivariate linear regression was performed to evaluate whether baseline predictors were associated with aortic growth.=.

Results

Of the 61 patients, 49 patients were included with MRI follow-up (n = 44) and/or adverse aortic events (n = 7). Six had undergone aortic surgery, no dissection/rupture occurred and one patient died during follow-up. During 8.0 [7.3-10.7] years of follow-up, AA growth rate was 0.40 ± 0.31 mm/year. After correction for confounders, AA curvature radius (p = 0.01), but not FD or PWV, was a predictor of AA dilatation. Only FD was associated with AA elongation (p = 0.01).

Conclusion

In Marfan and non-syndromic thoracic aortic aneurysm patients, ascending aorta curvature radius and flow displacement are associated with accelerated aortic growth at long-term follow-up. These markers may aid in the risk stratification of ascending aorta elongation and aneurysm formation.

Local aortic aneurysm wall expansion measured with automated image analysis

Background

Assessment of regional aortic wall deformation (RAWD) might better predict for abdominal aortic aneurysm (AAA) rupture than the maximal aortic diameter or growth rate. Using sequential computed tomography angiograms (CTAs), we developed a streamlined, semiautomated method of computing RAWD using deformable image registration (dirRAWD).

Methods

Paired sequential CTAs performed 1 to 2 years apart of 15 patients with AAAs of various shapes and sizes were selected. Using each patient’s initial CTA, the luminal and aortic wall surfaces were segmented both manually and semiautomatically. Next, the same patient’s follow-up CTA was aligned with the first using automated rigid image registration. Deformable image registration was then used to calculate the local aneurysm wall expansion between the sequential scans (dirRAWD). To measure technique accuracy, the deformable registration results were compared with the local displacement of anatomic landmarks (fiducial markers), such as the origin of the inferior mesenteric artery and/or aortic wall calcifications. Additionally, for each patient, the maximal RAWD was manually measured for each aneurysm and was compared with the dirRAWD at the same location.

Results

The technique was successful in all patients. The mean landmark displacement error was 0.59 ± 0.93 mm with no difference between true landmark displacement and deformable registration landmark displacement by Wilcoxon rank sum test (P = .39). The absolute difference between the manually measured maximal RAWD and dirRAWD was 0.27 ± 0.23 mm, with a relative difference of 7.9% and no difference using the Wilcoxon rank sum test (P = .69). No differences were found in the maximal dirRAWD when derived using a purely manual AAA segmentation compared with using semiautomated AAA segmentation (P = .55).

Conclusions

We found accurate and automated RAWD measurements were feasible with clinically insignificant errors. Using semiautomated AAA segmentations for deformable image registration methods did not alter maximal dirRAWD accuracy compared with using manual AAA segmentations. Future work will compare dirRAWD with finite element analysis–derived regional wall stress and determine whether dirRAWD might serve as an independent predictor of rupture risk.

Current abdominal aortic aneurysm (AAA) surveillance methods are limited to assessments of the maximal diameter, which cannot accurately predict for AAA expansion and rupture risk. Automated assessment of AAA expansion across the entire three-dimensional geometry of the aneurysm could better describe aneurysm growth and could substantially inform management decisions, including the indications for repair. We have developed an accurate and streamlined approach to assessing local three-dimensional AAA expansion with submillimeter accuracy using computed tomography imaging obtained during routine aneurysm surveillance. This novel process does not require significant user expertise nor computer processing power and can be performed using open-source software readily accessible to both scientists and clinicians.

Atlas-Based Evaluation of Hemodynamic in Ascending Thoracic Aortic Aneurysms

Atlas-based analyses of patients with cardiovascular diseases have recently been explored to understand the mechanistic link between shape and pathophysiology. The construction of probabilistic atlases is based on statistical shape modeling (SSM) to assess key anatomic features for a given patient population. Such an approach is relevant to study the complex nature of the ascending thoracic aortic aneurysm (ATAA) as characterized by different patterns of aortic shapes and valve phenotypes. This study was carried out to develop an SSM of the dilated aorta with both bicuspid aortic valve (BAV) and tricuspid aortic valve (TAV), and then assess the computational hemodynamic of virtual models obtained by the deformation of the mean template for specific shape boundaries (i.e., ±1.5 standard deviation, σ). Simulations demonstrated remarkable changes in the velocity streamlines, blood pressure, and fluid shear stress with the principal shape modes such as the aortic size (Mode 1), vessel tortuosity (Mode 2), and aortic valve morphologies (Mode 3). The atlas-based disease assessment can represent a powerful tool to reveal important insights on ATAA-derived hemodynamic, especially for aneurysms which are considered to have borderline anatomies, and thus challenging decision-making. The utilization of SSMs for creating probabilistic patient cohorts can facilitate the understanding of the heterogenous nature of the dilated ascending aorta.

Mesenchymal Stem Cells Alter MicroRNA Expression and Attenuate Thoracic Aortic Aneurysm Formation

BACKGROUND

Thoracic aortic aneurysms (TAA) are a progressive disease characterized by inflammation, smooth muscle cell activation and matrix degradation. We hypothesized that mesenchymal stem cells (MSCs) can immunomodulate vascular inflammation and remodeling via altered microRNA (miRNAs) expression profile to attenuate TAA formation.

MATERIALS AND METHODS

C57BL/6 mice underwent topical elastase application to form descending TAAs. Mice were also treated with MSCs on days 1 and 5 and aortas were analyzed on day 14 for aortic diameter. Cytokine array was performed in aortic tissue and total RNA was tagged and hybridized for miRNAs microarray analysis. Immunohistochemistry was performed for elastin degradation and leukocyte infiltration.

RESULTS

Treatment with MSCs significantly attenuated aortic diameter and TAA formation compared to untreated mice. MSC administration also attenuated T-cell, neutrophil and macrophage infiltration and prevented elastic degradation to mitigate vascular remodeling. MSC treatment also attenuated aortic inflammation by decreasing proinflammatory cytokines (CXCL13, IL-27, CXCL12 and RANTES) and upregulating anti-inflammatory interleukin-10 expression in aortic tissue of elastase-treated mice. TAA formation demonstrated activation of specific miRNAs that are associated with aortic inflammation and vascular remodeling. Our results also demonstrated that MSCs modulate a different set of miRNAs that are associated with decrease leukocyte infiltration and vascular inflammation to attenuate the aortic diameter and TAA formation.

CONCLUSIONS

These results indicate that MSCs immunomodulate specific miRNAs that are associated with modulating hallmarks of aortic inflammation and vascular remodeling of aortic aneurysms. Targeted therapies designed using MSCs and miRNAs have the potential to regulate the growth and development of TAAs.

Development and Validation of a Predictive Model to Identify Patients With an Ascending Thoracic Aortic Aneurysm

Background

Screening protocols do not exist for ascending thoracic aortic aneurysms (ATAAs). A risk prediction algorithm may aid targeted screening of patients with an undiagnosed ATAA to prevent aortic dissection. We aimed to develop and validate a risk model to identify those at increased risk of having an ATAA, based on readily available clinical information.

Methods and Results

This is a cross‐sectional study of computed tomography scans involving the chest at a tertiary care center on unique patients aged 50 to 85 years between 2013 and 2016. These criteria yielded 21 325 computed tomography scans. The double‐oblique technique was used to measure the ascending thoracic aorta, and an ATAA was defined as >40 mm in diameter. A logistic regression model was fitted for the risk of ATAA, with readily available demographics and comorbidity variables. Model performance was characterized by discrimination and calibration metrics via split‐sample testing. Among the 21 325 patients, there were 560 (2.6%) patients with an ATAA. The multivariable model demonstrated that older age, higher body surface area, history of arrhythmia, aortic valve disease, hypertension, and family history of aortic aneurysm were associated with increased risk of an ATAA, whereas female sex and diabetes were associated with a lower risk of an ATAA. The C statistic of the model was 0.723±0.016. The regression coefficients were transformed to scores that allow for point‐of‐care calculation of patients' risk.

Conclusions

We developed and internally validated a model to predict patients' risk of having an ATAA based on demographic and clinical characteristics. This algorithm may guide the targeted screening of an undiagnosed ATAA.

Wall Shear Stress Predicts Aortic Dilation in Patients With Bicuspid Aortic Valve

OBJECTIVES

This study sought to assess the predictive value of wall shear stress (WSS) for colocalized ascending aorta (AAo) growth rate (GR) in patients with bicuspid aortic valve (BAV).

BACKGROUND

BAV is associated with AAo dilation, but there is limited knowledge about possible predictors of aortic dilation in BAV patients with BAV. An increased WSS has been related to aortic wall damage in patients with BAV, but no previous prospective study tested its predictive value for dilation rate. Recently, a registration-based technique for the semiautomatic mapping of aortic GR has been presented and validated.

METHODS

Forty-seven patients with BAV free from valvular dysfunction prospectively underwent 4-dimensional flow cardiac magnetic resonance to compute WSS and subsequent follow-up with 2 electrocardiogram-gated high-resolution contrast-enhanced computed tomography angiograms for GR assessment.

RESULTS

During a median follow-up duration of 43 months, mid AAo GR was 0.24 mm/year. WSS and its circumferential component showed statistically significant association with mid AAo GR in bivariate (P = 0.049 and P = 0.014, respectively) and in multivariate analysis corrected for stroke volume and either baseline AAo diameter (P = 0.046 and P = 0.014, respectively) or z-score (P = 0.036 and P = 0.012, respectively). GR mapping further detailed that GR was heterogeneous in the AAo and that circumferential WSS, but not WSS magnitude, showed statistically significant positive associations with GR in the regions with the fastest growth.

CONCLUSIONS

4D flow cardiac magnetic resonance-derived WSS and, in particular, its circumferential component predict progressive dilation of the ascending aorta in patients with BAV. Thus, the assessment of WSS may be considered in the follow-up of these patients.

Ascending aortic aneurysm haemodynamics are associated with aortic wall biomechanical properties

OBJECTIVES

The effect of aortic haemodynamics on arterial wall properties in ascending thoracic aortic aneurysms (ATAAs) is not well understood. We aim to delineate the relationship between shear forces along the aortic wall and loco-regional biomechanical properties associated with the risk of aortic dissection.

METHODS

Five patients with ATAA underwent preoperative magnetic resonance angiogram and four-dimensional magnetic resonance imaging. From these scans, haemodynamic models were constructed to estimate maximum wall shear stress (WSS), maximum time-averaged WSS, average oscillating shear index and average relative residence time. Fourteen resected aortic samples from these patients underwent bi-axial tensile testing to determine energy loss (ΔUL) and elastic modulus (E10) in the longitudinal (ΔULlong, E10long) and circumferential (ΔULcirc, E10circ) directions and the anisotropic index (AI) for each parameter. Nine resected aortic samples underwent peel testing to determine the delamination strength (Sd). Haemodynamic indices were then correlated to the biomechanical properties.

RESULTS

A positive correlation was found between maximum WSS and ΔULlong rs=0.75, P = 0.002 and AIΔUL (rs=0.68, P=0.01). Increasing maximum time-averaged WSS was found to be associated with increasing ΔULlong (rs=0.73, P = 0.003) and AIΔUL (rs=0.62, P=0.02). Average oscillating shear index positively correlated with Sd (rs=0.73,P=0.04). No significant relationship was found between any haemodynamic index and E10, or between relative residence time and any biomechanical property.

CONCLUSIONS

Shear forces at the wall of ATAAs are associated with local degradation of arterial wall viscoelastic hysteresis (ΔUL) and delamination strength, a surrogate for aortic dissection. Haemodynamic indices may provide insights into aortic wall integrity, ultimately leading to novel metrics for assessing risks associated with ATAAs.

Vascular Deformation Mapping for CT Surveillance of Thoracic Aortic Aneurysm Growth

Background Aortic diameter measurements in patients with a thoracic aortic aneurysm (TAA) show wide variation. There is no technique to quantify aortic growth in a three-dimensional (3D) manner. Purpose To validate a CT-based technique for quantification of 3D growth based on deformable registration in patients with TAA. Materials and Methods Patients with ascending and descending TAA with two or more CT angiography studies between 2006 and 2020 were retrospectively identified. The 3D aortic growth was quantified using vascular deformation mapping (VDM), a technique that uses deformable registration to warp a mesh constructed from baseline aortic anatomy. Growth assessments between VDM and clinical CT diameter measurements were compared. Aortic growth was quantified as the ratio of change in surface area at each mesh element (area ratio). Manual segmentations were performed by independent raters to assess interrater reproducibility. Registration error was assessed using manually placed landmarks. Agreement between VDM and clinical diameter measurements was assessed using Pearson correlation and Cohen κ coefficients. Results A total of 38 patients (68 surveillance intervals) were evaluated (mean age, 69 years ± 9 [standard deviation]; 21 women), with TAA involving the ascending aorta (n = 26), descending aorta (n = 10), or both (n = 2). VDM was technically successful in 35 of 38 (92%) patients and 58 of 68 intervals (85%). Median registration error was 0.77 mm (interquartile range, 0.54-1.10 mm). Interrater agreement was high for aortic segmentation (Dice similarity coefficient = 0.97 ± 0.02) and VDM-derived area ratio (bias = 0.0, limits of agreement: -0.03 to 0.03). There was strong agreement (r = 0.85, P < .001) between peak area ratio values and diameter change. VDM detected growth in 14 of 58 (24%) intervals. VDM revealed growth outside the maximally dilated segment in six of 14 (36%) growth intervals, none of which were detected with diameter measurements. Conclusion Vascular deformation mapping provided reliable and comprehensive quantitative assessment of three-dimensional aortic growth and growth patterns in patients with thoracic aortic aneurysms undergoing CT surveillance. Published under a CC BY 4.0 license Online supplemental material is available for this article. See also the editorial by Wieben in this issue.

Fully automated guideline-compliant diameter measurements of the thoracic aorta on ECG-gated CT angiography using deep learning

Background

Manually performed diameter measurements on ECG-gated CT-angiography (CTA) represent the gold standard for diagnosis of thoracic aortic dilatation. However, they are time-consuming and show high inter-reader variability. Therefore, we aimed to evaluate the accuracy of measurements of a deep learning-(DL)-algorithm in comparison to those of radiologists and evaluated measurement times (MT).

Methods

We retrospectively analyzed 405 ECG-gated CTA exams of 371 consecutive patients with suspected aortic dilatation between May 2010 and June 2019. The DL-algorithm prototype detected aortic landmarks (deep reinforcement learning) and segmented the lumen of the thoracic aorta (multi-layer convolutional neural network). It performed measurements according to AHA-guidelines and created visual outputs. Manual measurements were performed by radiologists using centerline technique. Human performance variability (HPV), MT and DL-performance were analyzed in a research setting using a linear mixed model based on 21 randomly selected, repeatedly measured cases. DL-algorithm results were then evaluated in a clinical setting using matched differences. If the differences were within 5 mm for all locations, the cases was regarded as coherent; if there was a discrepancy >5 mm at least at one location (incl. missing values), the case was completely reviewed.

Results

HPV ranged up to ±3.4 mm in repeated measurements under research conditions. In the clinical setting, 2,778/3,192 (87.0%) of DL-algorithm's measurements were coherent. Mean differences of paired measurements between DL-algorithm and radiologists at aortic sinus and ascending aorta were -0.45±5.52 and -0.02±3.36 mm. Detailed analysis revealed that measurements at the aortic root were over-/underestimated due to a tilted measurement plane. In total, calculated time saved by DL-algorithm was 3:10 minutes/case.

Conclusions

The DL-algorithm provided coherent results to radiologists at almost 90% of measurement locations, while the majority of discrepent cases were located at the aortic root. In summary, the DL-algorithm assisted radiologists in performing AHA-compliant measurements by saving 50% of time per case.

Association between anion gap and mortality of aortic aneurysm in intensive care unit after open surgery

Background

There has not been a well-accepted prognostic model to predict the mortality of aortic aneurysm patients in intensive care unit after open surgery repair. Otherwise, our previous study found that anion gap was a prognosis factor for aortic aneurysm patients. Therefore, we wanted to investigate the relationship between anion gap and mortality of aortic aneurysm patients in intensive care unit after open surgery repair.

Methods

From Medical Information Mart for Intensive Care III, data of aortic aneurysm patients in intensive care unit after open surgery were enrolled. The primary clinical outcome was defined as death in intensive care unit. Univariate analysis was conducted to compare the baseline data in different groups stratified by clinical outcome or by anion gap level. Restricted cubic spline was drawn to find out the association between anion gap level and mortality. Subgroup analysis was then conducted to show the association in different level and was presented as frost plot. Multivariate regression models were built based on anion gap and were adjusted by admission information, severity score, complication, operation and laboratory indicators. Receiver operating characteristic curves were drawn to compare the prognosis ability of anion gap and simplified acute physiology score II. Decision curve analysis was finally conducted to indicate the net benefit of the models.

Results

A total of 405 aortic aneurysm patients were enrolled in this study and the in-intensive-care-unit (in-ICU) mortality was 6.9%. Univariate analysis showed that elevated anion gap was associated with high mortality (P value < 0.001), and restricted cubic spline analysis showed the positive correlation between anion gap and mortality. Receiver operating characteristic curve showed that the mortality predictive ability of anion gap approached that of simplified acute physiology score II and even performed better in predicting in-hospital mortality (P value < 0.05). Moreover, models based on anion gap showed that 1 mEq/L increase of anion gap improved up to 42.3% (95% confidence interval 28.5–59.8%) risk of death.

Conclusions

The level of serum anion gap was an important prognosis factor for aortic aneurysm mortality in intensive care unit after open surgery.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-02263-4.

Computation of a probabilistic and anisotropic failure metric on the aortic wall using a machine learning-based surrogate model

Scalar-valued failure metrics are commonly used to assess the risk of aortic aneurysm rupture and dissection, which occurs under hypertensive blood pressures brought on by extreme emotional or physical stress. To compute failure metrics under an elevated blood pressure, a classical patient-specific computer model consists of multiple computation steps involving inverse and forward analyses. These classical procedures may be impractical for time-sensitive clinical applications that require prompt feedback to clinicians. In this study, we developed a machine learning-based surrogate model to directly predict a probabilistic and anisotropic failure metric, namely failure probability (FP), on the aortic wall using aorta geometries at the systolic and diastolic phases. Ascending thoracic aortic aneurysm (ATAA) geometries of 60 patients were obtained from their CT scans, and biaxial mechanical testing data of ATAA tissues from 79 patients were collected. Finite element simulations were used to generate datasets for training, validation, and testing of the ML-surrogate model. The testing results demonstrated that the ML-surrogate can compute the maximum FP failure metric, with 0.42% normalized mean absolute error, in 1 s. To compare the performance of the ML-predicted probabilistic FP metric with other isotropic or deterministic metrics, a numerical case study was performed using synthetic "baseline" data. Our results showed that the probabilistic FP metric had more discriminative power than the deterministic Tsai-Hill metric, isotropic maximum principal stress, and aortic diameter criterion.

Marfan syndrome

Marfan syndrome (MFS) is an autosomal dominant, age-related but highly penetrant condition with substantial intrafamilial and interfamilial variability. MFS is caused by pathogenetic variants in FBN1, which encodes fibrillin-1, a major structural component of the extracellular matrix that provides support to connective tissues, particularly in arteries, the pericondrium and structures in the eye. Up to 25% of individuals with MFS have de novo variants. The most prominent manifestations of MFS are asymptomatic aortic root aneurysms, aortic dissections, dislocation of the ocular lens (ectopia lentis) and skeletal abnormalities that are characterized by overgrowth of the long bones. MFS is diagnosed based on the Ghent II nosology; genetic testing confirming the presence of a FBN1 pathogenetic variant is not always required for diagnosis but can help distinguish MFS from other heritable thoracic aortic disease syndromes that can present with skeletal features similar to those in MFS. Untreated aortic root aneurysms can progress to life-threatening acute aortic dissections. Management of MFS requires medical therapy to slow the rate of growth of aneurysms and decrease the risk of dissection. Routine surveillance with imaging techniques such as transthoracic echocardiography, CT or MRI is necessary to monitor aneurysm growth and determine when to perform prophylactic repair surgery to prevent an acute aortic dissection.

Psychological distress in response to physical activity restrictions in patients with non-syndromic thoracic aortic aneurysm/dissection

Individuals diagnosed with thoracic aortic aneurysm/dissection (TAAD) are given activity restrictions in an attempt to mitigate serious health complications and sudden death. The psychological distress resulting from activity restrictions has been established for other diseases or patient populations; however, individuals with non-syndromic TAAD have not been previously evaluated. Seventy-nine participants completed a questionnaire utilizing the Patient Health Questionnaire (PHQ-9) and Generalized Anxiety Disorder (GAD-7) questionnaires, which assess levels of depression and anxiety respectively. Additionally, quantitative and qualitative questions explored self-reported psychological distress in response to activity restrictions. Individuals who reported higher PHQ + GAD scores had been living with a diagnosis longer than two years (p = 0.0004), were between 35 and 65 years old (p = 0.05), reported not coping well (p = 0.0035), and reported physical activity was "very important" (p = 0.04). Results from individual questions showed that individuals who reported their diagnosis affected them financially were 3.5 times more likely to report "feeling nervous, anxious, or on edge" (CI = [0.81, 15.6], p = 0.094). Qualitative analysis revealed themes that identified participant beliefs regarding distress, ability to cope, hindrances to coping ability, and resources. These results show psychological distress can result from physical activity restrictions in non-syndromic TAAD individuals. Additionally, certain subpopulations may be more susceptible to distress. This is the first study to examine the psychological distress individuals with non-syndromic TAAD experience as a result of prescribed activity restrictions. Genetic counselors and other healthcare professionals can utilize this information to provide more tailored cardiovascular genetic counseling and increase its therapeutic potential for patients.

Significance of Hemodynamics Biomarkers, Tissue Biomechanics and Numerical Simulations in the Pathogenesis of Ascending Thoracic Aortic Aneurysms

Guidelines for the treatment of aortic wall diseases are based on measurements of maximum aortic diameter. However, aortic rupture or dissections do occur for small aortic diameters. Growing scientific evidence underlines the importance of biomechanics and hemodynamics in aortic disease development and progression. Wall shear stress (WWS) is an important hemodynamics marker that depends on aortic wall morphology and on the aortic valve function. WSS could be helpful to interpret aortic wall remodeling and define personalized risk criteria. The complementarity of Computational Fluid Dynamics and 4D Magnetic Resonance Imaging as tools for WSS assessment is a promising reality. The potentiality of these innovative technologies will provide maps or atlases of hemodynamics biomarkers to predict aortic tissue dysfunction. Ongoing efforts should focus on the correlation between these non-invasive imaging biomarkers and clinico-pathologic situations for the implementation of personalized medicine in current clinical practice.

Root Dilatation Is More Malignant Than Ascending Aortic Dilation

Background Data from the International Registry of Acute Aortic Dissection indicate that the guideline criterion of 5.5 cm for ascending aortic intervention misses many dissections occurring at smaller dimensions. Furthermore, studies of natural behavior have generally treated the aortic root and the ascending aorta as 1 unit despite embryological, anatomical, and functional differences. This study aims to disentangle the natural histories of the aforementioned aortic segments, allowing natural behavior to define specific intervention criteria for root and ascending segments of the aorta. Methods and Results Diameters of the aortic root and mid-ascending segment were measured separately. Long-term complications (dissection, rupture, and death) were analyzed retrospectively for 1162 patients with ascending thoracic aortic aneurysm. Cox regression analysis suggested that aortic root dilatation (P=0.017) is more significant in predicting adverse events than mid-ascending aortic dilatation (P=0.087). Short stature posed as a serious risk factor. The dedicated risk curves for the aortic root and the mid-ascending aorta revealed hinge points at 5.0 and 5.25 cm, respectively. Conclusions The natural histories of the aortic root and mid-ascending aorta are uniquely different. Dilation of the aortic root imparts a significant higher risk of adverse events. A diameter shift for intervention to 5.0 cm for the aortic root and to 5.25 cm for the mid-ascending aorta should be considered at expert centers.

Non-syndromic thoracic aortic aneurysm: cellular and molecular insights

Thoracic aortic aneurysm (TAA) develops silently and asymptomatically and is a major cause of mortality. TAA prevalence is greatly underestimated, it is usually diagnosed incidentally, and its treatment consists mainly of prophylactic surgery based on the aortic diameter. The lack of effective drugs and biological markers to identify and stratify TAAs by risk before visible symptoms results from scant knowledge of its pathophysiological mechanisms. Here we integrate the structural impairment affecting non-syndromic non-familial TAA with the main cellular and molecular changes described so far and consider how these changes are interconnected through specific pathways. The ultimate goal is to define much-needed novel markers of TAA, and so the potential of previously identified molecules to aid in early diagnosis/prognosis is also discussed. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

Trends and Outcomes of Elective Thoracic Aortic Repair and Acute Thoracic Aortic Syndromes in the United States

BACKGROUND

There is a paucity of data on the contemporary outcomes and trends of elective thoracic aortic aneurysm repair and aneurysm-associated acute aortic syndrome.

METHODS

We queried the National Inpatient Sample (NIS) database years 2012-2016 to identify hospitalizations for elective thoracic aortic aneurysm repair and aneurysm-associated acute aortic syndrome. The main study outcome was in-hospital mortality.

RESULTS

The analysis yielded 24,295 hospitalizations for elective thoracic aortic aneurysm repair and 8875 hospitalizations for aneurysm-associated acute aortic syndrome. The number of hospitalizations for elective aortic repair significantly increased from 4375 in 2012 to 5450 in 2016 (P_trend = .01). The number of hospitalizations for acute aortic syndrome numerically increased from 1545 in 2012 to 2340 in 2016 (P_trend = .10). Overall in-hospital mortality for elective aortic repair was 2.4% with no change over time. In-hospital mortality for acute aortic rupture was 39.4% and for acute aortic dissection was 6.2% with no change over time. Hospitalizations for elective aortic repair had lower incidence of complications compared with those for aneurysm-associated acute aortic syndrome, including cardiogenic shock, cardiac arrest, acute stroke, and shorter length of stay. Factors associated with higher mortality among admissions undergoing elective aortic repair included older age, heart failure, valvular disease, and chronic kidney disease. Older age, coagulopathy, and fluid/ electrolytes disorders were associated with increased mortality among those with acute aortic syndrome.

CONCLUSION

Contemporary elective thoracic aortic aneurysm repair is associated with lower in-hospital mortality and morbidity when compared with a clinical presentation for an aneurysm-associated acute aortic syndrome. This should be taken into account when deciding the timing of elective aortic aneurysm repair and balancing the risks and benefits.

Mapping pre-dissection aortic wall abnormalities: a multiparametric assessment

OBJECTIVES

Maximal aortic diameter is commonly used to assess aortic risk but poorly predicts the timing and location of dissection events in patients with connective tissue disease who undergo regular imaging surveillance. Hence, we aimed to use available surveillance computed tomography angiography (CTA) scans to investigate the correlation between 3-dimensional (3D) growth and cyclic transmural wall stress with the location of intimal tear formation.

METHODS

Three type B aortic dissection patients with 2 available electrocardiogram (ECG)-gated pre-dissection CTA scans and without surgical repair during the pre-dissection interval were retrospectively identified at our institution. Vascular deformation mapping was used to measure 3D aortic growth between 2 pre-dissection clinical CTA studies. In addition, we performed a computational analysis to estimate cyclic transmural wall stress in patient-specific baseline CTA geometries.

RESULTS

In all 3 connective tissue disease patients, the site of type B aortic intimal tear co-localized with areas of peak 3D aortic wall growth. Aortic growth was detected by clinical radiological assessment in only 1 case. Co-localization of peak transmural stress and the site of intimal tear formation were found in all cases.

CONCLUSIONS

Focal areas of growth and transmural wall stress co-localized with the site of intimal tear formation. These hypothesis-generating results suggest a possible new analytic pathway for a more sophisticated assessment of the factors leading to the initiation of dissection in patients with connective tissue disease. These methods could improve on current risk-stratification techniques.

Echocardiographic changes in the shape and size of the aortic cusps in dogs with confirmed systemic hypertension

Systemic hypertension (SH) in dogs typically occurs secondary to renal disease, diabetes mellitus, hyperadrenocorticism, malignant adrenal tumors, or various medications. Echocardiography performed on people with SH has shown asymmetric dilation of the sinuses at the level of the aortic valves, previously undescribed in canine patients. The objective of this retrospective case-control study was to determine if there was a difference in size and shape of the aortic cusps at the level of the sinus of Valsalva in dogs with SH compared to dogs with normal blood pressure. We reviewed echocardiographic findings in 74 dogs with SH and 37 dogs with normal blood pressure (NBP), defined as less than 150 mmHg. Systemic hypertension was classified as mild (150-159 mm Hg), moderate (160-179 mm Hg), or severe (greater than 180 mm Hg). There was a significant difference (P < .001) in the mean size of the aorta cusps at the level of the sinuses in 67 of 74 dogs with SH and none of 37 dogs with NBP. Of the 74 dogs with SH, 70 had left ventricular hypertrophy (18 asymmetric, 15 concentric, and 37 eccentric). Additionally, there was aortic root dilatation in 15 dogs, aortic insufficiency in 21, mitral regurgitation in 50, and left atrial enlargement in 71. The standard deviation of the three cusp measurements between the dogs with SH and dogs with NBP had a sensitivity of 92% and specificity of 97% for diagnosis of SH. Asymmetric size of the aortic cusps on echocardiography is therefore a reliable indicator of SH in dogs.

Hybrid repair versus conventional open repair for thoracic aortic arch aneurysms

BACKGROUND

Thoracic aortic arch aneurysms (TAAs) can be a life-threatening condition due to the potential risk of rupture. Treatment is recommended when the risk of rupture is greater than the risk of surgical complications. Depending on the cause, size and growth rate of the TAA, treatment may vary from close observation to emergency surgery. Aneurysms of the thoracic aorta can be managed by a number of surgical techniques. Open surgical repair (OSR) of aneurysms involves either partial or total replacement of the aorta, which is dependent on the extent of the diseased segment of the aorta. During OSR, the aneurysm is replaced with a synthetic graft. Hybrid repair (HR) involves a combination of open surgery with endovascular aortic stent graft placement. Hybrid repair requires varying degrees of invasiveness, depending on the number of supra-aortic branches that require debranching. The hybrid technique that combines supra-aortic vascular debranching with stent grafting of the aortic arch has been introduced as a therapeutic alternative. However, the short- and long-term outcomes of HR remain unclear, due to technical difficulties and complications as a result of the angulation of the aortic arch as well as handling of the arch during surgery.

OBJECTIVES

To assess the effectiveness and safety of HR versus conventional OSR for the treatment of TAAs.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL and AMED databases and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 22 March 2021. We also searched references of relevant articles retrieved from the electronic search for additional citations.

SELECTION CRITERIA

We considered for inclusion in the review all published and unpublished randomised controlled trials (RCTs) and controlled clinical trials (CCTs) comparing HR to OSR for TAAs.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened all titles and abstracts obtained from the literature search to identify those that met the inclusion criteria. We retrieved the full text of studies deemed as potentially relevant by at least one review author. The same review authors screened the full-text articles independently for inclusion or exclusion.

MAIN RESULTS

No RCTs or CCTs met the inclusion criteria for this review.

AUTHORS' CONCLUSIONS

Due to the lack of RCTs or CCTs, we were unable to determine the safety and effectiveness of HR compared to OSR in people with TAAs, and we are unable to provide high-certainty evidence on the optimal surgical intervention for this cohort of patients. High-quality RCTs or CCTs are necessary, addressing the objective of this review.

Combining 4D Flow MRI and Complex Networks Theory to Characterize the Hemodynamic Heterogeneity in Dilated and Non-dilated Human Ascending Aortas

Motivated by the evidence that the onset and progression of the aneurysm of the ascending aorta (AAo) is intertwined with an adverse hemodynamic environment, the present study characterized in vivo the hemodynamic spatiotemporal complexity and organization in human aortas, with and without dilated AAo, exploring the relations with clinically relevant hemodynamic and geometric parameters. The Complex Networks (CNs) theory was applied for the first time to 4D flow magnetic resonance imaging (MRI) velocity data of ten patients, five of them presenting with AAo dilation. The time-histories along the cardiac cycle of velocity-based quantities were used to build correlation-based CNs. The CNs approach succeeded in capturing large-scale coherent flow features, delimiting flow separation and recirculation regions. CNs metrics highlighted that an increasing AAo dilation (expressed in terms of the ratio between the maximum AAo and aortic root diameter) disrupts the correlation in forward flow reducing the correlation persistence length, while preserving the spatiotemporal homogeneity of secondary flows. The application of CNs to in vivo 4D MRI data holds promise for a mechanistic understanding of the spatiotemporal complexity and organization of aortic flows, opening possibilities for the integration of in vivo quantitative hemodynamic information into risk stratification and classification criteria.

Global Burden of Aortic Aneurysm and Attributable Risk Factors from 1990 to 2017

Background

To date, our understanding of the global aortic aneurysm (AA) burden distribution is very limited.

Objective

To assess a full view of global AA burden distribution and attributable risk factors from 1990 to 2017.

Methods

We extracted data of AA deaths, disability-adjusted life years (DALYs), and their corresponding age-standardized rates (ASRs), in general and by age/sex from the 2017 Global Burden of Disease (GBD) study. The current AA burden distribution in 2017 and its changing trend from 1990 to 2017 were separately showed. The spatial divergence was discussed from four levels: global, five social-demographic index regions, 21 GBD regions, and 195 countries and territories. We also estimated the risk factors attributable to AA related deaths.

Results

Globally, the AA deaths were 167,249 with an age-standardized death rate (ASDR) of 2.19/100,000 persons in 2017, among which the elderly and the males accounted for the majority. Although reductions in ASRs were observed in developed areas, AA remained an important health issue in those relatively underdeveloped areas and might be much more important in the near future. AA may increasingly affect the elderly and the female population. Similar patterns of AA DALYs burden were noted during the study period. AA burden attributable to high blood pressure and smoking decreased globally and there were many heterogeneities in their distribution.

Discussion

AA maintained an incremental public health issue worldwide. The change pattern of AA burden was heterogeneous across locations, ages, and sexes and it is paramount to improve resource allocation for more effective and targeted prevention strategies. Also, prevention of tobacco consumption and blood pressure control should be emphasized.

Weighted miRNA co-expression network reveals potential roles of apoptosis related pathways and crucial genes in thoracic aortic aneurysm

Background

Thoracic aortic aneurysm (TAA) is a potentially life-threatening disease for which few medical therapies are available. Thus, it is critically important to investigate the underlying molecular mechanisms of TAA, and identify potential targets for TAA treatment.

Methods

Differentially expressed miRNAs (DEMs) and differentially expressed genes (DEGs) were screened, and a weighted correlation network analysis (WGCNA) was employed to construct a weighted miRNA co-expression network using GSE110527. The DEMs were then mapped into the whole co-expression network of all samples, and a DEM coexpression network was created. Molecular Complex Detection (MCODE) was used to identify crucial miRNAs. Target genes were predicted using the miRTarbase database, and further screened by identifying genes that overlapped with the DEGs of GSE26155. The screened target genes were validated using GSE9106, and the successfully validated genes were considered as crucial genes. Finally, a miRNA risk score for diagnosing TAA was calculated by undertaking a least absolute shrinkage and selection operator (LASSO) regression.

Results

The tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) signaling pathway was found in DEM functional enrichment. Crucial miRNAs were identified and target genes were predicted and associated with the regulation of the TRAIL signaling pathway. Next, 113 important target genes were identified as overlapping with the DEGs of GSE26155. These genes were further validated, and 5 successfully validated genes were considered as crucial genes. Finally, the miRNA risk score calculated by the LASSO regression was shown to have potential diagnostic value.

Conclusions

We performed a WGCNA analysis to construct a weighted miRNA co-expression network, predicted target genes of crucial miRNAs, identified crucial genes, and finally calculated a miRNA risk score. The results showed that pathways and genes associated with apoptosis appear to play an important role in TAA pathogenesis, and that medications targeting apoptosis might slow TAA progression. Future in vitro and in vivo experimental studies need to be undertaken to further validate our findings and investigate the mechanistic details of these crucial miRNAs and crucial genes.

Impact of Instructions for Use and Endoleaks On Long-Term Mortality After Treatment for Abdominal Aortic Aneurysm

OBJECTIVES

We reported the clinical outcomes after open repair and endovascular aortic repair for abdominal aortic aneurysm and analyzed the risk factors for all-cause mortality and endoleak after endovascular aortic repair.

METHODS

Patients who underwent elective treatment for abdominal aortic aneurysm from January 2009 to March 2020 were included in this study. The treatment was according to a procedure selection algorithm based on the Society for Vascular Surgery comorbidity scores and instructions for use. All patients were divided into open repair and endovascular aortic repair groups, and the clinical results were compared between the groups.

RESULTS

Of the 278 patients, 116 patients (41.9%) underwent open repair, and 161 patients (58.1%) underwent endovascular aortic repair. The cumulative survival rate with endovascular aortic repair was 78.6%. In the Cox proportional hazard analysis, hemodialysis (hazard ratio = 4.56; 95% confidence interval = 1.5-14.0) and the presence of type I or III endoleak (hazard ratio = 5.7; 95% confidence interval = 1.50-14.5) were independent risk factors for all-cause mortality. The Society for Vascular Surgery comorbidity score was not an independent risk factor (hazard ratio = 1.11; 95% confidence interval = 1.0-1.2). In the multivariate logistic regression analysis to identify the risk factors for type I or III endoleak after endovascular aortic repair, anticoagulation drug therapy (odds ratio = 3.99; 95% confidence interval = 1.8-8.9), untreated thoracic aortic aneurysm (odds ratio = 4.8; 95% confidence interval = 1.8-17.3), and outside instruction for use for the proximal neck (odds ratio = 5.8; 95% confidence interval = 2.3-9.8) were independent risk factors.

CONCLUSIONS

We analyzed the risk factors for all-cause mortality after treatment and endoleak after endovascular aortic repair. The results indicated that the instructions for use should be respected to reduce the frequency of endoleaks and that open repair should be chosen more often to improve late survival.