Genes Associated with Thoracic Aortic Aneurysm and Dissection: 2019 Update and Clinical Implications

Genetic insights from a Brazilian cohort of aortopathies through targeted next-generation sequencing and FBN1 direct sequencing

Thoracic aortic diseases (or aortopathies) result from complex interactions between genetic and hemodynamic factors. Often clinically silent, these diseases can lead to lethal complications such as aortic dissection or rupture. This study focused on a Brazilian cohort of 79 individuals with thoracic aortic diseases and explored genetic factors through targeted next-generation sequencing (tNGS) of 15 priority genes and FBN1 direct sequencing. The majority of individuals had nonsyndromic aortopathy, with eight diagnosed with Marfan syndrome (MFS). Pathogenic or likely pathogenic variants (PV/LPV) were found in five genes, namely, FBN1, ACTA2, TGFBR2, MYLK, and SMAD3. Notably, novel variants in FBN1 were identified that contributed to Marfan-like phenotypes. The diagnostic yield for isolated aortopathies was 7.1%, which increased to 55.5% for syndromic cases. Variants of uncertain significance (VUS) were identified, emphasizing the need for further research and familial investigations to refine variant classifications. This study provides valuable insights into the genetic landscape of aortopathies in Brazil, aiding early diagnosis and personalized management.

Clinical effectiveness of genetic testing guidelines in patients with thoracic aortic aneurysms

OBJECTIVE

To analyze the effectiveness of the current genetic testing guidelines for patients with thoracic aortic aneurysms.

METHODS

We evaluated genetic tests for thoracic aortic disease (TAD) from 2012 to 2023 in patients aged 18 and older with a thoracic aorta diameter greater than 4 cm. Mutation rates were compared by American College of Cardiology/American Heart Association testing criteria met by patients: age younger than 60 years, syndromic features of connective tissue diseases (CTDs), family history, or none. Results were classified as pathogenic, variants of uncertain significance (VUS), or negative. Genes tested were analyzed in 2 categories: primary (strongly associated with heritable diseases) or secondary (less strongly associated).

RESULTS

In total, 1034 patients were included: 42.4% aged younger than 60 years, 19.1% with syndromic features of CTD, 41.8% with family history, and 30.7% meeting no criteria. Overall, 3.97% had pathogenic mutations, and 27.27% had VUS. Mutation rates were greatest in patients with syndromic features of CTD (13.2%), followed by patients aged younger than 60 years (5.48%), with a family history (4.63%), and with no criteria met (2.21%). Primary genes had pathogenic mutation rates of 3.29% and VUS rates of 12.19%. Secondary genes had lower pathogenic rates (0.68%) but greater VUS (17.5%). Mutation rates in primary genes peaked at 22% in patients meeting all criteria, whereas those younger than 60 years without family history or syndromic features of CTD had the lowest rate (0.54%).

CONCLUSIONS

Refining genetic testing guidelines to incorporate multiple patient criteria could enhance risk stratification and support informed decision-making in genetic testing for TAD. Limiting testing to genes strongly associated with TAD could lower VUS rates.

Prevalence and Influence of Genetic Variants on Follow-Up Results in Patients Surviving Thoracic Aortic Therapy

Background/Objective: To investigate the prevalence and effects of genetic variants (GVs) in survivors of thoracic aortic dissection/aneurysm repair. Methods: Patients aged 18-80 years who survived follow-up after cardiosurgical or endovascular repair of thoracic aortic aneurysm or dissection at a single tertiary center between 2008 and 2019 and underwent genetic testing were enrolled. The exclusion criteria were age >60 years, no offspring, and inflammatory- or trauma-related pathogenesis. Follow-up entailed computed tomography-angiography at 3 and 9 months and annually thereafter. All patients underwent genetic analyses of nine genes using next-generation sequencing. In cases of specific suspicion, the analysis was expanded to include 32 genes. Results: The study included 95 patients. The follow-up period was 3 ± 2.5 years. GVs were detected in 40% of patients. Correlation analysis according to primary diagnosis showed no significant correlation in disease persistence, progression, or in reintervention rates in aneurysm patients and a correlation of disease persistence with genetic variants according to variant class in dissection patients (p = 0.037). Correlation analysis according to follow-up CD finding revealed that patients with detected dissection, irrespective of original pathology, showed a strong correlation with genetic variants regarding disease progression and reintervention rates (p = 0.012 and p = 0.047, respectively). Conclusions: The prevalence of VUS is high in patients with aortic pathology. In patients with dissected aorta in the follow-up, irrespective of original pathology, genetic variants correlate with higher reintervention rates, warranting extended-spectrum genetic testing. The role of VUS may be greater than is currently known.

Clinical Interpretation of Genetic Variants in the Evaluation and Management of Thoracic Aortic Aneurysm and Dissection

BACKGROUND

We aimed to elucidate clinical implications of genetic variant interpretation in assessing disease severity and progression in thoracic aortic aneurysm and dissection (TAAD) patients.

METHODS

Consecutive TAAD patients with aortic root and/or ascending aortic aneurysms seen between 2011 and 2020 were included. Serial echocardiography, family history of TAAD, and management information were retrospectively collected and analyzed. Patients were classified into gene-positive (Gen-P), variants of uncertain significance, and gene-negative (Gen-N) groups.

RESULTS

A total of 407 patients were included: mean age 53.7 ± 15.4 years, 64.4% men, and 38% with reported family history of TAAD. Thirty-seven (9.1%) were Gen-P; 147 (36.1%) had a variant of uncertain significance. The maximal aneurysm diameter was 4.78 mm larger in Gen-P than the other groups (P < .001). In 162 unoperated TAAD patients with serial echocardiographic measurements, aneurysms enlarged at a significantly higher rate in the Gen-P (1.36 mm/year, 95% CI: 0.77-1.95) than variants of uncertain significance and Gen-N groups (0.83 mm/year vs 0.89 mm/year, respectively; P < .001). Aneurysms were 20% more likely to require surgical intervention for every millimeter increase in diameter. When considered on an individual basis, the highest growth rates were found in the variants of uncertain significance group.

CONCLUSIONS

While aneurysms linked to variants of uncertain significance demonstrate average growth rates comparable to those in Gen-N, close follow-up and genetic counseling in the variants of uncertain significance group are recommended for assessment of pathogenicity on a case-by-case basis. Early familial gene testing in TAAD is important to develop individualized preventive and therapeutic criteria.

Contributions of Germline and Somatic Mosaic Genetics to Thoracic Aortic Aneurysms in Nonsyndromic Individuals

BACKGROUND

Thoracic aortic aneurysm (TAA) is associated with significant morbidity and mortality. Although individuals with family histories of TAA often undergo clinical molecular genetic testing, adults with nonsyndromic TAA are not typically evaluated for genetic causes. We sought to understand the genetic contribution of both germline and somatic mosaic variants in a cohort of adult individuals with nonsyndromic TAA at a single center.

METHODS AND RESULTS

One hundred eighty-one consecutive patients <60 years who presented with nonsyndromic TAA at the Massachusetts General Hospital underwent deep (>500×) targeted sequencing across 114 candidate genes associated with TAA and its related functional pathways. Samples from 354 age- and sex-matched individuals without TAA were also sequenced, with a 2:1 matching. We found significant enrichments for germline (odds ratio [OR], 2.44, P=4.6×10-6 [95% CI, 1.67-3.58]) and also somatic mosaic variants (OR, 4.71, P=0.026 [95% CI, 1.20-18.43]) between individuals with and without TAA. Likely genetic causes were present in 24% with nonsyndromic TAA, of which 21% arose from germline variants and 3% from somatic mosaic alleles. The 3 most frequently mutated genes in our cohort were FLNA (encoding Filamin A), NOTCH3 (encoding Notch receptor 3), and FBN1 (encoding Fibrillin-1). There was increased frequency of both missense and loss of function variants in TAA individuals.

CONCLUSIONS

Likely contributory dominant acting genetic variants were found in almost one quarter of nonsyndromic adults with TAA. Our findings suggest a more extensive genetic architecture to TAA than expected and that genetic testing may improve the care and clinical management of adults with nonsyndromic TAA.

Therapeutic potential of natural products and underlying targets for the treatment of aortic aneurysm

Aortic aneurysm is a vascular disease characterized by irreversible vasodilatation that can lead to dissection and rupture of the aortic aneurysm, a life-threatening condition. Thoracic aortic aneurysm (TAA) and abdominal aortic aneurysm (AAA) are two main types. The typical treatments for aortic aneurysms are open surgery and endovascular aortic repair, which are only indicated for more severe patients. Most patients with aneurysms have an insidious onset and slow progression, and there are no effective drugs to treat this stage. The inability of current animal models to perfectly simulate all the pathophysiological states of human aneurysms may be the key to this issue. Therefore, elucidating the molecular mechanisms of this disease, finding new therapeutic targets, and developing effective drugs to inhibit the development of aneurysms are the main issues of current research. Natural products have been applied for thousands of years to treat cardiovascular disease (CVD) in China and other Asian countries. In recent years, natural products have combined multi-omics, computational biology, and integrated pharmacology to accurately analyze drug components and targets. Therefore, the multi-component and multi-target complexity of natural products have made them a potentially ideal treatment for multifactorial diseases such as aortic aneurysms. Natural products have regained popularity worldwide. This review provides an overview of the known natural products for the treatment of TAA and AAA and searches for potential cardiovascular-targeted natural products that may treat TAA and AAA based on various cellular molecular mechanisms associated with aneurysm development.

Marfan and Loeys-Dietz aortic phenotype: A potential tool for diagnosis and management

Objective

In heritable aortic diseases, different vascular involvement may occur with potential variable implications in aortic dilation/dissection risk. This study aimed to analyze the aortic anatomy of individuals with Marfan syndrome and Loeys-Dietz syndrome to identify possible morphological differences.

Methods

Computed tomography and magnetic resonance imaging of the thoracoabdominal aorta from the proximal supra-aortic vessels to the femoral bifurcation level of 114 patients with Marfan and Loeys-Dietz syndromes and 20 matched control subjects were examined. Aortic diameters, areas, length, and tortuosity were measured in different aortic segments using specific vessel analysis software.

Results

Patients with Marfan syndrome showed a higher prevalence of ascending aorta and aortic root dilation (P = .011), larger and longer aortic roots (P = .013) with pear-shaped phenotype, larger isthmus/descending aorta diameter ratio (P = .015), and larger suprarenal aorta and iliac arteries. Patients with Loeys-Dietz syndrome showed longer indexed segments and a significantly longer arch (P = .006) with type 2/3 arch prevalence (P = .097). Measurement ratios analysis provided cut-off values (aortic root to ascending aorta length/aortic root diameter, aortic root/sinotubular junction, aortic root/ascending aorta diameter) differentiating patients with Marfan syndrome from patients with Loeys-Dietz syndrome, even in the early stage of the disease.

Conclusions

Both syndromes show peculiar anatomic patterns at different aortic levels irrespective of aortic dilation and disease severity. These features may represent the expression of different genetic mutations on aortic development, with a potential impact on prognosis and possibly contributing to better management of the diseases. The systematic adoption of whole body imaging with magnetic resonance or computed tomography should always be considered, because they allow a complete vascular assessment with practical indicators of differential diagnosis.

Heritable thoracic aortic disease: a literature review on genetic aortopathies and current surgical management

Heritable thoracic aortic disease puts patients at risk for aortic aneurysms, rupture, and dissections. The diagnosis and management of this heterogenous patient population continues to evolve. Last year, the American Heart Association/American College of Cardiology Joint Committee published diagnosis and management guidelines for aortic disease, which included those with genetic aortopathies. Additionally, evolving research studying the implications of underlying genetic aberrations with new genetic testing continues to become available. In this review, we evaluate the current literature surrounding the diagnosis and management of heritable thoracic aortic disease, as well as novel therapeutic approaches and future directions of research.

Evaluation of the Value of Histological Examination for the Prediction of Genetic Thoracic Proximal Aortopathies

Background: Heritable connective tissue disorders are often accompanied by an increased risk for thoracic aortic aneurysm and dissection (TAAD). Profound knowledge of the underlying pathology may have an impact on individual treatment, systematic follow-up, and early detection by the screening of offspring. The aim of this study, based in a single high-volume tertiary center, was an analysis of the diagnostic validity of histopathologic findings in patients with TAAD due to these findings' accuracy in diagnosing heritable connective tissue disorders. Methods: Therefore, genetic testing by next-generation sequencing (NGS) was performed to evaluate the correlations. In total, 65 patients with TAAD undergoing surgical treatment before the age of 60 years or with age up to 80 years if they had offspring at the time of the procedure were included in the analysis. Results: In our cohort, no certain correlation of histological findings to the results of genetic diagnostics in patients with clinically relevant aortic pathology could be shown. Patients with histopathologic findings for heritable connective tissue disorder and a positive gene variant were 11.6 years younger than patients without mutation and without histological evidence for connective tissue disorder. Conclusions: Genetic clarification is useful to define the specific genotype of the disease of the aortic wall in the case of non-specific histological characteristics.

Understanding genomic medicine for thoracic aortic disease through the lens of induced pluripotent stem cells

Thoracic aortic disease (TAD) is often silent until a life-threatening complication occurs. However, genetic information can inform both identification and treatment at an early stage. Indeed, a diagnosis is important for personalised surveillance and intervention plans, as well as cascade screening of family members. Currently, only 20% of heritable TAD patients have a causative mutation identified and, consequently, further advances in genetic coverage are required to define the remaining molecular landscape. The rapid expansion of next generation sequencing technologies is providing a huge resource of genetic data, but a critical issue remains in functionally validating these findings. Induced pluripotent stem cells (iPSCs) are patient-derived, reprogrammed cell lines which allow mechanistic insights, complex modelling of genetic disease and a platform to study aortic genetic variants. This review will address the need for iPSCs as a frontline diagnostic tool to evaluate variants identified by genomic discovery studies and explore their evolving role in biological insight through to drug discovery.

Prevalence of Genetic Variants and Deep Phenotyping in Patients with Thoracic Aortic Aneurysm and Dissection: A Cross-Sectional Single-Centre Cohort Study

BACKGROUND

There is a paucity of evidence on people with thoracic aortic aneurysm and dissection. We aimed to determine the prevalence of genetic variants and their associations with phenotypes.

METHODS

In this cross-sectional single-centre cohort study of consecutive patients who underwent endovascular or open-surgical repair of thoracic aortic aneurysm and dissection, genetic analysis was performed using four-stage Next Generation Sequencing, and findings were confirmed with Sanger sequencing. We collected personal and family history on comorbidities, clinical examination, anthropometrics, skeletal deformities, joint function, and ophthalmological measures. Cardiovascular risk and phenotype scores were calculated.

RESULTS

Ninety-five patients were eligible (mean age 54 ± 9 years, 70% males, 56% aortic dissection). One-fifth had a family history of aortic disease. Furthermore, 95% and 54% had a phenotype score of ≤5 and ≤2, respectively. There were no significant differences in the distribution of phenotype characteristics according to age, sex, aortic pathology, or performed invasive procedures. Genetic variants of uncertain significance were detected in 40% of patients, with classic mutations comprising 18% of all variants. We observed no significant association with cardiovascular and phenotype scores but with higher joint function scores (p = 0.015).

CONCLUSION

Genetic variants are highly present in clinically relevant aortic pathologies. Variants appear to play a larger role than previously described. The different variants do not correlate with specific phenotypes, age, pathology, sex, or family history.

The Aortic Team Model and Collaborative Decision Pathways for the Management of Complex Aortic Disease: Clinical Practice Update From the Canadian Cardiovascular Society/Canadian Society of Cardiac Surgeons/Canadian Society for Vascular Surgery/Canadian Association for Interventional Radiology

Disease of the aortic arch, descending thoracic, or thoracoabdominal aorta necessitates dedicated expertise across medical, endovascular, and surgical specialties. Cardiologists, cardiac surgeons, vascular surgeons, interventional radiologists, and others have expertise and skills that aid in the management of patients with complex aortic disease. No specialty is uniformly expert in all aspects of required care. Because of this dispersion of expertise across specialties, an aortic team model approach to decision-making and treatment is advocated. A nonhierarchical partnership across specialties within an interdisciplinary aortic clinic ensures that all treatment options are considered and promotes shared decision-making between the patient and all aortic experts. Furthermore, regionalization of care for aortic disease of increased complexity assures that the breadth of treatment options is available and that favourable volume-outcome ratios for high-risk procedures are maintained. An awareness of best practice care pathways for patient referrals for preventative management, acute care scenarios, chronic care scenarios, and pregnancy might facilitate a more organized management schema for aortic disease across Canada and improve lifelong surveillance initiatives.

Giant ascending aortic aneurysm with impending rupture as presentation of cutis laxa 1B: a case report

Background

Thoracic aortic aneurysms are rarely symptomatic but can result in acute aortic syndromes, associated with a high mortality rate. While most cases may be acquired, a genetic basis is evident in approximately 20-25% of the cases, especially among patients under 50 years of age, and those exhibiting syndromic features or family history. Although autosomal dominant inheritance is predominant in familial aortopathies, exceptions exist, such as cutis laxa 1B (CL1B)-related aortic disease, caused by variants in EFEMP2 gene, that follows an autosomal recessive inheritance pattern.

Case summary

We present the case of a 26-year-old male with a giant ascending aorta aneurysm and massive pericardial effusion, which was ultimately diagnosed of CL1B due to the p.Ser137Cys variant in the EFEMP2 gene in homozygosis. The patient underwent successful ascending aorta replacement (Bentall´s procedure). There were not complications or further events after 2 years of follow-up.

Discussion

This case underscores the importance of genetic testing in young patients presenting with aortopathies, syndromic features, or atypical presentations, irrespective of family history.

Double Heterozygous Pathogenic Variants in the LOX and PKD1 Genes in a 5-Year-Old Patient with Thoracic Aortic Aneurysm and Polycystic Kidney Disease

Familial thoracic aortic aneurysms and dissections may occur as an isolated hereditary trait or as part of connective tissue disorders with Mendelian inheritance, but severe cardiovascular disease in pediatric patients is extremely rare. There is growing knowledge on pathogenic variants causing the disease; however, much of the phenotypic variability and gene-gene interactions remain to be discovered. We present a case report of a 5.5-year-old girl with an aortic aneurysm and concomitant polycystic kidney disease. Whole exome sequencing was performed, followed by family screening by amplicon deep sequencing and diagnostic imaging studies. In the proband, two pathogenic variants were identified: p.Tyr257Ter in the LOX gene inherited from her mother, and p.Thr2977Ile in the PKD1 gene inherited from her father. All adult carriers of either of these variants showed symptoms of aortic disease. We conclude that the coexistence of two independent genetic variants in the proband may be the reason for an early onset of disease.

Genetic Overlap of Spontaneous Dissection of Either the Thoracic Aorta or the Coronary Arteries

Ascending thoracic aortic dissection (ATAD) is a well-known vascular cause of sudden death. Spontaneous coronary artery dissections (SCAD) are emerging as an important cause of early-onset myocardial infarction and sudden death. Genetic variants in multiple connective tissue genes have been recognized to underlie ATAD; other genetic variants have similarly been recognized to underlie SCAD. Little data are available regarding any genetic commonality between ATAD and SCAD. Our objective is to determine and characterize any genetic overlap between genes coding for ATAD and SCAD. We identified and reviewed 17 retrospective and prospective genetic studies of thoracic aortic dissection and SCAD published between 2016 and 2022 identified through PubMed and Orbis. Articles highlighting the significant plausible triggers for ATAD or SCAD individually were analyzed. No previous study reviewed both ATAD and SCAD genetics together. Separate lists of causative genes were constructed for ATAD and SCAD-and then commonalities were sought. A Venn diagram was constructed to display the genetic overlap and common physiologic pathways involved. We identified a definite, meaningful overlap of 15 independent genes based on a genome-wide association study or other genetic methods. The associated genetic pathways involved various biologic processes including elastin degradation, smooth muscle cell function, and the TGFβ-pathway. The overlapping genes included the following: COL3A1, TGFB2, SMAD3, MYLK, TGFBR2, TGFBR1, LOX, FBN1, NOTCH1, ELN, COL5A1, COL5A2, COL1A2, MYH11, and TLN1. The corresponding molecular pathways were investigated and correlated for both diseases. We are not aware of other studies searching for genetic commonalities between ATAD and SCAD. We have successfully identified overlapping genes-and their corresponding molecular pathways-for ATAD and SCAD. We hope that these insights will lead to further clinical and scientific understanding of each disease through study of their fundamental commonalities.

"Big Data" Analyses Underlie Clinical Discoveries at the Aortic Institute

This issue of the Yale Journal of Biology and Medicine (YJBM) focuses on Big Data and precision analytics in medical research. At the Aortic Institute at Yale New Haven Hospital, the vast majority of our investigations have emanated from our large, prospective clinical database of patients with thoracic aortic aneurysm (TAA), supplemented by ultra-large genetic sequencing files. Among the fundamental clinical and scientific discoveries enabled by application of advanced statistical and artificial intelligence techniques on these clinical and genetic databases are the following: From analysis of Traditional "Big Data" (Large data sets). 1. Ascending aortic aneurysms should be resected at 5 cm to prevent dissection and rupture. 2. Indexing aortic size to height improves aortic risk prognostication. 3. Aortic root dilatation is more malignant than mid-ascending aortic dilatation. 4. Ascending aortic aneurysm patients with bicuspid aortic valves do not carry the poorer prognosis previously postulated. 5. The descending and thoracoabdominal aorta are capable of rupture without dissection. 6. Female patients with TAA do more poorly than male patients. 7. Ascending aortic length is even better than aortic diameter at predicting dissection. 8. A "silver lining" of TAA disease is the profound, lifelong protection from atherosclerosis. From Modern "Big Data" Machine Learning/Artificial Intelligence analysis: 1. Machine learning models for TAA: outperforming traditional anatomic criteria. 2. Genetic testing for TAA and dissection and discovery of novel causative genes. 3. Phenotypic genetic characterization by Artificial Intelligence. 4. Panel of RNAs "detects" TAA. Such findings, based on (a) long-standing application of advanced conventional statistical analysis to large clinical data sets, and (b) recent application of advanced machine learning/artificial intelligence to large genetic data sets at the Yale Aortic Institute have advanced the diagnosis and medical and surgical treatment of TAA.

Epigenetic Reader Bromodomain-Containing Protein 4 in Aging-Related Vascular Pathologies and Diseases: Molecular Basis, Functional Relevance, and Clinical Potential

Aging is a key independent risk factor of various vascular diseases, for which the regulatory mechanisms remain largely unknown. Bromodomain-containing protein 4 (BRD4) is a member of the Bromodomain and Extra-Terminal domain (BET) family and is an epigenetic reader playing diverse roles in regulating transcriptional elongation, chromatin remodeling, DNA damage response, and alternative splicing in various cells and tissues. While BRD4 was initially recognized for its involvement in cancer progression, recent studies have revealed that the aberrant expression and impaired function of BRD4 were highly associated with aging-related vascular pathology, affecting multiple key biological processes in the vascular cells and tissues, providing new insights into the understanding of vascular pathophysiology and pathogenesis of vascular diseases. This review summarizes the recent advances in BRD4 biological function, and the progression of the studies related to BRD4 in aging-associated vascular pathologies and diseases, including atherosclerosis, aortic aneurism vascular neointima formation, pulmonary hypertension, and essential hypertension, providing updated information to advance our understanding of the epigenetic mechanisms in vascular diseases during aging and paving the way for future research and therapeutic approaches.

Comparison of Genes Associated with Thoracic and Abdominal Aortic Aneurysms

Aneurysms impacting the ascending thoracic aorta and the abdominal aorta affect patient populations with distinct clinical characteristics. Through a literature review, this paper compares the genetic associations of ascending thoracic aortic aneurysm (ATAA) with abdominal aortic aneurysms (AAA). Genes related to atherosclerosis, lipid metabolism, and tumor development are associated specifically with sporadic AAA, while genes controlling extracellular matrix (ECM) structure, ECM remodeling, and tumor growth factor β function are associated with both AAA and ATAA. Contractile element genes uniquely predispose to ATAA. Aside from known syndromic connective tissue disease and poly-aneurysmal syndromes (Marfan disease, Loeys-Dietz syndrome, and Ehlers-Danlos syndrome), there is only limited genetic overlap between AAA and ATAA. The rapid advances in genotyping and bioinformatics will elucidate further the various pathways associated with the development of aneurysms affecting various parts of the aorta.

The natural history of aortic root aneurysms

The aortic root has a different embryologic origin from all other segments of the human aorta, a feature that likely confers unique susceptibilities, anatomical patterns, and clinical behavior of aneurysm disease in this vital location. In this manuscript, we review the natural history of ascending aortic aneurysm, with a specific focus on the aortic root. The specific central message is that root dilatation is more malignant than ascending dilatation.

Nonsize Criteria for Surgical Intervention on the Ascending Thoracic Aorta

For decades, aortic surgery has relied on size criteria for intervention on the ascending aorta. While diameter has served well, diameter alone falls short of an ideal criterion. Herein, we examine the potential application of other, nondiameter criteria in aortic decision-making. These findings are summarized in this review. We have conducted multiple investigations of specific alternate nonsize criteria by leveraging our extensive database, which includes complete, verified anatomic, clinical, and mortality data on 2,501 patients with thoracic aortic aneurysm (TAA) and dissections (198 Type A, 201 Type B, and 2102 TAAs). We examined 14 potential intervention criteria. Each substudy had its own specific methodology, reported individually in the literature. The overall findings of these studies are presented here, with a special emphasis on how the findings can be incorporated into enhanced aortic decision-making-above and beyond sheer diameter. The following nondiameter criteria have been found useful in decision-making regarding surgical intervention. (1) Pain: In the absence of other specific cause, substernal chest pain mandates surgery. Well-developed afferent neural pathways carry warning signals to the brain. (2) Aortic length/tortuosity: Length is emerging as a mildly better predictor of impending events than diameter. (3) Genes: Specific genetic aberrations provide a powerful predictor of aortic behavior; malignant genetic variants obligate earlier surgery. (4) Family history: Aortic events closely follow those in relatives with a threefold increase in likelihood of aortic dissection for other family members once an index family dissection has occurred. (5) Bicuspid aortic valve: Previously thought to increase aortic risk (as a "Marfan light" situation), current data show that bicuspid valve is not a predictor of higher risk. (6) Diabetes actually protects against aortic events, via mural thickening and fibrosis. (7) Biomarkers: A specialized "RNA signature test" identifies aneurysm-bearing patients in the general population and promises to predict impending dissection. (8) Aortic stress: Blood pressure (BP) elevation from anxiety/exertion precipitates dissection, especially with high-intensity weightlifting. (9) Root dilatation imposes higher dissection risk than supracoronary ascending aneurysm. (10) Inflammation on positron emission tomography (PET) imaging implies high rupture risk and merits surgical intervention. (11) A KIF6 p.Trp719Arg variant elevates aortic dissection risk nearly two-fold. (12) Female sex confers some increased risk, which can be largely accommodated by using body-size-based nomograms (especially height nomograms). (13) Fluoroquinolones predispose to catastrophic dissection events and should be avoided rigorously in aneurysm patients. (14) Advancing age makes the aorta more vulnerable, increasing likelihood of dissection. In conclusion, nondiameter criteria can beneficially be brought to bear on the decision to observe or operate on specific TAA.

Risk Prediction Models for Management of Patients following Acute Aortic Dissection

Risk prediction of adverse outcomes post aortic dissection is dependet not only on the postdissection-associated clinical factors but on the very foundation of the risk factors that lead up to the dissection itself. There are various such risk factors existing prior to the dissection which impact the postdissection outcomes. In this paper, we review the literature to critically analyze various risk models, burdened by their significant limitations, that attempt to stratify risk prediction based on postdissection patient characteristics. We further review several studies across the literature that investigate the diverse set of predissection risk factors impacting postdissection outcomes. We have discussed and appraised numerous studies which attempt to develop a tool to stratify risk prediction by incorporating the impacts of different factors: malperfusion, blood biochemistry, and perioperative outcomes. The well-validated Penn classification has clearly demonstrated in the literature the significant impact that malperfusion has on adverse outcomes postdissection. Other risk models, already severely hindered by their limitations, lack such validation. We further discuss additional alluded risk factors, including the impact of predissection aortic size, the syndromic and nonsyndromic natures of dissection, and the effects of family history and genetics, which collectively contribute to the risk of adverse outcomes postdissection and prognosis. To achieve the goal of a true risk model, there remains the vital need for appreciation and appropriate consideration for all such aforementioned factors, from before and after the dissection, as discussed in this paper. By being able to incorporate the value of true risk prediction for a patient into the decision-making framework, it will allow a new page of precision medical decision-making to be written.

Arterial dissections: Common features and new perspectives

Arterial dissections, which involve an abrupt tear in the wall of a major artery resulting in the intramural accumulation of blood, are a family of catastrophic disorders causing major, potentially fatal sequelae. Involving diverse vascular beds, including the aorta or coronary, cervical, pulmonary, and visceral arteries, each type of dissection is devastating in its own way. Traditionally they have been studied in isolation, rather than collectively, owing largely to the distinct clinical consequences of dissections in different anatomical locations - such as stroke, myocardial infarction, and renal failure. Here, we review the shared and unique features of these arteriopathies to provide a better understanding of this family of disorders. Arterial dissections occur commonly in the young to middle-aged, and often in conjunction with hypertension and/or migraine; the latter suggesting they are part of a generalized vasculopathy. Genetic studies as well as cellular and molecular investigations of arterial dissections reveal striking similarities between dissection types, particularly their pathophysiology, which includes the presence or absence of an intimal tear and vasa vasorum dysfunction as a cause of intramural hemorrhage. Pathway perturbations common to all types of dissections include disruption of TGF-β signaling, the extracellular matrix, the cytoskeleton or metabolism, as evidenced by the finding of mutations in critical genes regulating these processes, including LRP1, collagen genes, fibrillin and TGF-β receptors, or their coupled pathways. Perturbances in these connected signaling pathways contribute to phenotype switching in endothelial and vascular smooth muscle cells of the affected artery, in which their physiological quiescent state is lost and replaced by a proliferative activated phenotype. Of interest, dissections in various anatomical locations are associated with distinct sex and age predilections, suggesting involvement of gene and environment interactions in disease pathogenesis. Importantly, these cellular mechanisms are potentially therapeutically targetable. Consideration of arterial dissections as a collective pathology allows insight from the better characterized dissection types, such as that involving the thoracic aorta, to be leveraged to inform the less common forms of dissections, including the potential to apply known therapeutic interventions already clinically available for the former.

HTAD patient pathway: Strategy for diagnostic work-up of patients and families with (suspected) heritable thoracic aortic diseases (HTAD). A statement from the HTAD working group of VASCERN

Heritable thoracic aortic diseases (HTAD) are rare pathologies associated with thoracic aortic aneurysms and dissection, which can be syndromic or non-syndromic. They may result from genetic defects. Associated genes identified to date are classified into those encoding components of the (a) extracellular matrix (b) TGFβ pathway and (c) smooth muscle contractile mechanism. Timely diagnosis allows for prompt aortic surveillance and prophylactic surgery, hence improving life expectancy and reducing maternal complications as well as providing reassurance to family members when a diagnosis is ruled out. This document is an expert opinion reflecting strategies put forward by medical experts and patient representatives involved in the HTAD Rare Disease Working Group of VASCERN. It aims to provide a patient pathway that improves patient care by diminishing time to diagnosis, facilitating the establishment of a correct diagnosis using molecular genetics when possible, excluding the diagnosis in unaffected persons through appropriate family screening and avoiding overuse of resources. It is being recommended that patients are referred to an expert centre for further evaluation if they meet at least one of the following criteria: (1) thoracic aortic dissection (<70 years if hypertensive; all ages if non-hypertensive), (2) thoracic aortic aneurysm (all adults with Z score >3.5 or 2.5-3.5 if non-hypertensive or hypertensive and <60 years; all children with Z score >3), (3) family history of HTAD with/without a pathogenic variant in a gene linked to HTAD, (4) ectopia lentis without other obvious explanation and (5) a systemic score of >5 in adults and >3 in children. Aortic imaging primarily relies on transthoracic echocardiography with magnetic resonance imaging or computed tomography as needed. Genetic testing should be considered in those with a high suspicion of underlying genetic aortopathy. Though panels vary among centers, for patients with thoracic aortic aneurysm or dissection or systemic features these should include genes with a definitive or strong association to HTAD. Genetic cascade screening and serial aortic imaging should be considered for family screening and follow-up. In conclusion, the implementation of these strategies should help standardise the diagnostic work-up and follow-up of patients with suspected HTAD and the screening of their relatives.

Pathogenic variants in arteriopathy genes detected in a targeted sequencing study: Penetrance and 1-year outcomes after return of results

PURPOSE

We estimated the penetrance of pathogenic/likely pathogenic (P/LP) variants in arteriopathy-related genes and assessed near-term outcomes following return of results.

METHODS

Participants (N = 24,520) in phase III of the Electronic Medical Records and Genomics network underwent targeted sequencing of 68 actionable genes, including 9 genes associated with arterial aneurysmal diseases. Penetrance was estimated on the basis of the presence of relevant clinical traits. Outcomes occurring within 1 year of return of results included new diagnoses, referral to a specialist, new tests ordered, surveillance initiated, and new medications started.

RESULTS

P/LP variants were present in 34 participants. The average penetrance across genes was 59%, ranging from 86% for FBN1 variants to 25% for SMAD3. Of 16 participants in whom results were returned, 1-year outcomes occurred in 63%. A new diagnosis was made in 44% of the participants, 56% were referred to a specialist, a new test was ordered in 44%, surveillance was initiated in 31%, and a new medication was started in 31%.

CONCLUSION

Penetrance of P/LP variants in arteriopathy-related genes, identified in a large, targeted sequencing study, was variable and overall lower than that reported in clinical cohorts. Meaningful outcomes within the first year were noted in 63% of participants who received results.

Methamphetamine induces thoracic aortic aneurysm/dissection through C/EBPβ

AIMS

Thoracic aortic aneurysm/dissection (TAAD) is a life-threatening disease with diverse clinical manifestations. Although the association between methamphetamine (METH) and TAAD is frequently observed, the causal relationship between METH abuse and aortic aneurysm/dissection has not been established. This study was designed to determine if METH causes aortic aneurysm/dissection and delineate the underlying mechanism.

METHODS AND RESULTS

A new TAAD model was developed by exposing METH to SD rats pre-treated with lysyl oxidase inhibitor β-aminopropionitrile (BAPN). Combination of METH and BAPN caused thoracic aortic aneurysm/dissection in 60% of rats. BAPN+METH significantly increased the expression and activities of both matrix metalloproteinase MMP2 and MMP9, consistent with the severe elastin breakage and dissection. Mechanistically, METH increased CCAAT-enhancer binding protein β (C/EBPβ) expression by enhancing mothers against decapentaplegic homolog 3 (Smad3) and extracellular regulated protein kinase (ERK1/2) signaling. METH also promoted C/EBPβ binding to MMP2 and MMP9 promoters. Blocking C/EBPβ significantly attenuated METH+BAPN-induced TAAD and MMP2/MMP9 expression. Moreover, BAPN+METH promoted aortic medial smooth muscle cell (SMC) apoptosis through C/EBPβ-mediated IGFBP5/p53/PUMA signaling pathways. More importantly, the expression of C/EBPβ, MMP2/MMP9, and apoptosis-promoting proteins was increased in the aorta of human patients with thoracic aortic dissection, suggesting that the mechanisms identified in animal study could be relevant to human disease.

CONCLUSIONS

Our study demonstrated that METH exposure has a casual effect on TAAD. C/EBPβ mediates METH-introduced TAAD formation by causing elastin breakage, medial cell loss and degeneration. Therefore, C/EBPβ may be a potential factor for TAAD clinical diagnosis or treatment.

Neural operator learning of heterogeneous mechanobiological insults contributing to aortic aneurysms

Thoracic aortic aneurysm (TAA) is a localized dilatation of the aorta that can lead to life-threatening dissection or rupture. In vivo assessments of TAA progression are largely limited to measurements of aneurysm size and growth rate. There is promise, however, that computational modelling of the evolving biomechanics of the aorta could predict future geometry and properties from initiating mechanobiological insults. We present an integrated framework to train a deep operator network (DeepONet)-based surrogate model to identify TAA contributing factors using synthetic finite-element-based datasets. For training, we employ a constrained mixture model of aortic growth and remodelling to generate maps of local aortic dilatation and distensibility for multiple TAA risk factors. We evaluate the performance of the surrogate model for insult distributions varying from fusiform (analytically defined) to complex (randomly generated). We propose two frameworks, one trained on sparse information and one on full-field greyscale images, to gain insight into a preferred neural operator-based approach. We show that this continuous learning approach can predict the patient-specific insult profile associated with any given dilatation and distensibility map with high accuracy, particularly when based on full-field images. Our findings demonstrate the feasibility of applying DeepONet to support transfer learning of patient-specific inputs to predict TAA progression.

Evolving Mural Defects, Dilatation, and Biomechanical Dysfunction in Angiotensin II-Induced Thoracic Aortopathies

BACKGROUND

Thoracic aortopathy associates with extracellular matrix remodeling and altered biomechanical properties. We sought to quantify the natural history of thoracic aortopathy in a common mouse model and to correlate measures of wall remodeling such as aortic dilatation or localized mural defects with evolving microstructural composition and biomechanical properties of the wall.

METHODS

We combined a high-resolution multimodality imaging approach (panoramic digital image correlation and optical coherence tomography) with histopathologic examinations and biaxial mechanical testing to correlate spatially, for the first time, macroscopic mural defects and medial degeneration within the ascending aorta with local changes in aortic wall composition and mechanical properties.

RESULTS

Findings revealed strong correlations between local decreases in elastic energy storage and increases in circumferential material stiffness with increasing proximal aortic diameter and especially mural defect size. Mural defects tended to exhibit a pronounced biomechanical dysfunction that is driven by an altered organization of collagen and elastic fibers.

CONCLUSIONS

While aneurysmal dilatation is often observed within particular segments of the aorta, dissection and rupture initiate as highly localized mechanical failures. We show that wall composition and material properties are compromised in regions of local mural defects, which further increases the dilatation and overall structural vulnerability of the wall. Identification of therapies focused on promoting robust collagen accumulation may protect the wall from these vulnerabilities and limit the incidence of dissection and rupture.

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.

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.

Update on the molecular landscape of thoracic aortic aneurysmal disease

PURPOSE OF THE REVIEW

Thoracic aortic aneurysms and dissections (TAADs) are a major health problem in the Western population. This review summarises recent discoveries in the genetic landscape of TAAD disease, discusses current challenges in clinical practice, and describes the molecular road ahead in TAAD research. Disorders, in which aneurysmal disease is not observed in the thoracic aorta, are not discussed.

RECENT FINDINGS

Current gene discovery studies have pinpointed about 40 genes associated with TAAD risk, accounting for about 30% of the patients. Importantly, novel genes, and their subsequent functional characterisation, have expanded the knowledge on disease-related pathways providing crucial information on key elements in this disease, and it pinpoints new therapeutic targets. Moreover, current molecular evidence also suggests the existence of less monogenic nature of TAAD disease, in which the presentation of a diseased patient is most likely influenced by a multitude of genetic and environmental factors.

SUMMARY CLINICAL PRACTICE/RELEVANCE

Ongoing molecular genetic research continues to expand our understanding on the pathomechanisms underlying TAAD disease in order to improve molecular diagnosis, optimise risk stratification, advance therapeutic strategies and facilitate counselling of TAAD patients and their families.

A multiphasic model for determination of water and solute transport across the arterial wall: effects of elastic fiber defects

Transport of solute across the arterial wall is a process driven by both convection and diffusion. In disease, the elastic fibers in the arterial wall are disrupted and lead to altered fluid and mass transport kinetics. A computational mixture model was used to numerically match previously published data of fluid and solute permeation experiments in groups of mouse arteries with genetic (knockout of fibulin-5) or chemical (treatment with elastase) disruption of elastic fibers. A biphasic model of fluid permeation indicated the governing property to be the hydraulic permeability, which was estimated to be 1.52×10^-9, 1.01×10^-8, and 1.07×10^-8 mm⁴/μN.s for control, knockout, and elastase groups, respectively. A multiphasic model incorporating solute transport was used to estimate effective diffusivities that were dependent on molecular weight, consistent with expected transport behaviors in multiphasic biological tissues. The effective diffusivity for the 4 kDA FITC-dextran solute, but not the 70 or 150 kDa FITC-dextran solutes, was dependent on elastic fiber structure, with increasing values from control to knockout to elastase groups, suggesting that elastic fiber disruption affects transport of lower molecular weight solutes. The model used here sets the groundwork for future work investigating transport through the arterial wall.

Good performance of the criteria of American College of Medical Genetics and Genomics/Association for Molecular Pathology in prediction of pathogenicity of genetic variants causing thoracic aortic aneurysms and dissections

BACKGROUND

The identification of pathogenic variant in patients with thoracic aortic aneurysms and dissections (TAAD) was previously found to be a significant indicator pointing to earlier need for surgical intervention. In order to evaluate available methods for classifying identified genetic variants we have compared the event-free survival in a cohort of TAAD patients classified as genotype-positive versus genotype-negative by the American College of Medical Genetics and Genomics and the Association for Molecular Pathology (ACMG-AMP) criteria or by ClinVar database.

METHODS

We analyzed previously unreported cohort of 132 patients tested in the routine clinical setting for genetic variants in a custom panel of 30 genes associated with TAAD or the TruSight Cardio commercial panel of 174 genes associated with cardiac disease. The identified variants were classified using VarSome platform. Kaplan-Meier survival curves were constructed to compare the event-free survival between probands defined as 'genotype-positive' and 'genotype-negative' using different classifications in order to compare their performance.

RESULTS

Out of 107 rare variants found, 12 were classified as pathogenic/likely pathogenic by ClinVar, 38 were predicted to be pathogenic/likely pathogenic by ACMG. Variant pathogenicity as assessed by ACMG criteria was a strong predictor of event free survival (event free survival at 50 years 83% vs. 50%, for genotype positive patients vs. reference, respectively, p  = 0.00096). The performance of ACMG criteria was similar to that of ClinVar (event free survival at 50 years 87% vs. 50%, for genotype positive patients vs. reference, respectively p  = 0.023) but independent from it as shown by analysing variants with no ClinVar record (event free survival at 50 years 80% vs. 50%, p  = 0.0039). Variants classified as VUS by ACMG criteria or ClinVar did not affect event-free survival. TAAD specific custom gene panel performed similar to the larger universal cardiac panel.

CONCLUSIONS

In our cohort of unrelated TAAD patients ACMG classification tool available at VarSome was useful in assessing pathogenicity of novel genetic variants. Gene panel containing the established genes associated with the highest risk of hereditary TAAD (ACTA1, COL3A1, FBN1, MYH11, SMAD3, TGFB2, TGFBR1, TGFBR2, MYLK) was sufficient to identify prevailing majority of variants most likely to be causative of the disease.

Phenotyping Zebrafish Mutant Models to Assess Candidate Genes Associated with Aortic Aneurysm

(1) Background: Whole Exome Sequencing of patients with thoracic aortic aneurysm often identifies "Variants of Uncertain Significance" (VUS), leading to uncertainty in clinical management. We assess a novel mechanism for potential routine assessment of these genes in TAA patients. Zebrafish are increasingly used as experimental models of disease. Advantages include low cost, rapid maturation, and physical transparency, permitting direct microscopic assessment. (2) Methods: Zebrafish loss of function mutations were generated using a CRISPRC/CAS9 approach for EMILIN1 and MIB1 genes similar to VUSs identified in clinical testing. Additionally, "positive control" mutants were constructed for known deleterious variants in FBN1 (Marfan's) and COL1A2, COL5A1, COL5A2 (Ehlers-Danlos). Zebrafish embryos were followed to six days post-fertilization. Embryos were studied by brightfield and confocal microscopy to ascertain any vascular, cardiac, and skeletal abnormalities. (3) Results: A dramatic pattern of cardiac, cerebral, aortic, and skeletal abnormalities was identified for the known pathogenic FBN1 and COL1A2, COL5A1, and COL5A2 mutants, as well as for the EMILIN1 and MIB1 mutants of prior unknown significance. Visualized abnormalities included hemorrhage (peri-aortic and cranial), cardiomegaly, reduced diameter of the aorta and intersegmental vessels, lower aortic cell counts, and scoliosis (often extremely severe). (4) Conclusion: This pilot study suggests that candidate genes arising in clinical practice may be rapidly assessed via zebrafish mutants-thus permitting evidence-based decisions about pathogenicity. Thus, years-long delays to clinically demonstrate pathogenicity may be obviated. Zebrafish data would represent only one segment of analysis, which would also include frequency of the variant in the general population, in silico genetic analysis, and degree of preservation in phylogeny.

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.

A human importin-β-related disorder: Syndromic thoracic aortic aneurysm caused by bi-allelic loss-of-function variants in IPO8

Importin 8, encoded by IPO8, is a ubiquitously expressed member of the importin-β protein family that translocates cargo molecules such as proteins, RNAs, and ribonucleoprotein complexes into the nucleus in a RanGTP-dependent manner. Current knowledge of the cargoes of importin 8 is limited, but TGF-β signaling components such as SMAD1-4 have been suggested to be among them. Here, we report that bi-allelic loss-of-function variants in IPO8 cause a syndromic form of thoracic aortic aneurysm (TAA) with clinical overlap with Loeys-Dietz and Shprintzen-Goldberg syndromes. Seven individuals from six unrelated families showed a consistent phenotype with early-onset TAA, motor developmental delay, connective tissue findings, and craniofacial dysmorphic features. A C57BL/6N Ipo8 knockout mouse model recapitulates TAA development from 8-12 weeks onward in both sexes but most prominently shows ascending aorta dilatation with a propensity for dissection in males. Compliance assays suggest augmented passive stiffness of the ascending aorta in male Ipo8^-/- mice throughout life. Immunohistological investigation of mutant aortic walls reveals elastic fiber disorganization and fragmentation along with a signature of increased TGF-β signaling, as evidenced by nuclear pSmad2 accumulation. RT-qPCR assays of the aortic wall in male Ipo8^-/- mice demonstrate decreased Smad6/7 and increased Mmp2 and Ccn2 (Ctgf) expression, reinforcing a role for dysregulation of the TGF-β signaling pathway in TAA development. Because importin 8 is the most downstream TGF-β-related effector implicated in TAA pathogenesis so far, it offers opportunities for future mechanistic studies and represents a candidate drug target for TAA.

Analysis of the contribution of 129 candidate genes to thoracic aortic aneurysm or dissection of a mixed cohort of sporadic and familial cases in South China

Thoracic aortic aneurysm or dissection (TAAD) is a group of life-threatening complex diseases after symptomatic onset with genetic heterogeneity accounting for approximately 20% of cases. Previously, we identified 40 rare variants in 11 TAAD-related core genes among 70 TAAD patients by next-generation sequencing. In this study, we further analyzed the variants in the disease-causing genes in 129 cases of sporadic TAAD and 22 familial cases by whole-exome sequencing. A total of 116 variants in 47 TAAD-related genes were identified, 64.7% (75/116) of which occurred in sporadic TAAD without syndromes, and among these genes, FBN1 was the most common TAAD-related gene. Of the 26.7% (31/116) that were pathogenic or likely pathogenic, almost one third were from sporadic cases without syndromes involving FBN1, SMAD3, SMAD6, MYH11, TGFBR1, MYLK, LOX and LTBP3. Interestingly, the novel VUS (variant of uncertain significance) *879Glu in MCTP2 occurred in two unrelated probands with sporadic acute aortic dissection without a bicuspid aortic valve. Furthermore, more than one variant was detected in 24 patients, and 70.8% (17/24) occurred in sporadic cases. Younger individuals were more likely to carry P/LP (pathogenic or likely pathogenic) variants and harbor more variants. P/LP carriers seem to have a larger aortic diameter, lower D-dimer levels, and a shorter ICU length of stay but longer hospitalization time. In conclusion, we expanded the candidate gene profile of TAAD, especially for sporadic cases without syndromic features. VUSs need further clarification.

Factors Associated with Mutations: Their Matching Rates to Cardiovascular and Neurological Diseases

Monogenic hypertension is rare and caused by genetic mutations, but whether factors associated with mutations are disease-specific remains uncertain. Given two factors associated with high mutation rates, we tested how many previously known genes match with (i) proximity to telomeres or (ii) high adenine and thymine content in cardiovascular diseases (CVDs) related to vascular stiffening. We extracted genomic information using a genome data viewer. In human chromosomes, 64 of 79 genetic loci involving >25 rare mutations and single nucleotide polymorphisms satisfied (i) or (ii), resulting in an 81% matching rate. However, this high matching rate was no longer observed as we checked the two factors in genes associated with essential hypertension (EH), thoracic aortic aneurysm (TAA), and congenital heart disease (CHD), resulting in matching rates of 53%, 70%, and 75%, respectively. A matching of telomere proximity or high adenine and thymine content projects the list of loci involving rare mutations of monogenic hypertension better than those of other CVDs, likely due to adoption of rigorous criteria for true-positive signals. Our data suggest that the factor–disease matching rate is an accurate tool that can explain deleterious mutations of monogenic hypertension at a >80% match—unlike the relatively lower matching rates found in human genes of EH, TAA, CHD, and familial Parkinson’s disease.

Aneurysms and dissections - What is new in the literature of 2019/2020 - a European Society of Vascular Medicine annual review

More than 6,000 publications were found in PubMed concerning aneurysms and dissections, including those Epub ahead of print in 2019, printed in 2020. Among those publications 327 were selected and considered of particular interest.