Update on the genetic risk for thoracic aortic aneurysms and acute aortic dissections: implications for clinical care

Identification of Genetic Variants Associated with Hereditary Thoracic Aortic Diseases (HTADs) Using Next Generation Sequencing (NGS) Technology and Genotype-Phenotype Correlations

Hereditary thoracic aorta diseases (HTADs) are a heterogeneous group of rare disorders whose major manifestation is represented by aneurysm and/or dissection frequently located at the level of the ascending thoracic aorta. The diseases have an insidious evolution and can be encountered as an isolated manifestation or can also be associated with systemic, extra-aortic manifestations (syndromic HTADs). Along with the development of molecular testing technologies, important progress has been made in deciphering the heterogeneous etiology of HTADs. The aim of this study is to identify the genetic variants associated with a group of patients who presented clinical signs suggestive of a syndromic form of HTAD. Genetic testing based on next-generation sequencing (NGS) technology was performed using a gene panel (Illumina TruSight Cardio Sequencing Panel) or whole exome sequencing (WES). In the majority of cases (8/10), de novo mutations in the FBN1 gene were detected and correlated with the Marfan syndrome phenotype. In another case, a known mutation in the TGFBR2 gene associated with Loeys-Dietz syndrome was detected. Two other pathogenic heterozygous variants (one de novo and the other a known mutation) in the SLC2A10 gene (compound heterozygous genotype) were identified in a patient diagnosed with arterial tortuosity syndrome (ATORS). We presented the genotype-phenotype correlations, especially related to the clinical evolution, highlighting the particularities of each patient in a family context. We also emphasized the importance of genetic testing and patient monitoring to avoid acute aortic events.

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.

A national cross-sectional survey on time-trends for endovascular repair of genetically-triggered aortic disease and connective tissue disorders over two decades

BACKGROUND

By this survey, we aim to gain national-based information regarding trends in endovascular repair (ER) for the treatment of aortic disease in patients with genetically-triggered aortic disease (GTAD) and connective tissue disorder (CTD) over the last two decades.

METHODS

All Italian vascular surgery centers (N.=80) were invited to participate in an anonymous electronic cross-sectional survey on ER for GTAD/CTD.

RESULTS

Overall, 29 institutions completed the survey, thereby yielding a 36% response rate. The percentage of responding institutions rises to 64% if only regional hubs were considered (23/36). The median number of index procedures per center was 6.2, and a steady increase in the overall number of interventions over time was also noted. Most patients were males (73%) with a median age of 48 years. The most common endovascular procedure was TEVAR (N.=101), followed by F/BEVAR (N.=43) and EVAR (N.=37). The overall technical success rate was 83.4% while major adverse events and mortality at thirty days were reported at 18.2% and 9.9%, respectively. An additional 5.0% mortality rate was noted for an overall one-year mortality of 14.9%, while 3.7% of all treated patients were diagnosed with a type 1 endoleak.

CONCLUSIONS

This national cross-sectional survey, investigating trends in ER of GTADs and CTDs over two decades, highlights a consistent increase in the use of endovascular techniques for their treatment. Early mortality was acceptably low, yet influenced by the urgency of presentation. At one-year follow-up, a 5% additional death rate was noted, and the reintervention rate remained below one in ten.

Identification of Variants of Uncertain Significance in the Genes Associated with Thoracic Aortic Disease in Russian Patients with Nonsyndromic Sporadic Subtypes of the Disorder

Nonsyndromic sporadic thoracic aortic aneurysm (nssTAA) is characterized by diverse genetic variants that may vary in different populations. Our aim was to identify clinically relevant variants in genes implicated in hereditary aneurysms in Russian patients with nssTAA. Forty-one patients with nssTAA without dissection were analyzed. Using massive parallel sequencing, we searched for variants in exons of 53 known disease-causing genes. Patients were found to have no (likely) pathogenic variants in the genes of hereditary TAA. Six variants of uncertain significance (VUSs) were identified in four (9.8%) patients. Three VUSs [FBN1 c.7841C>T (p.Ala2614Val), COL3A1 c.2498A>T (p.Lys833Ile), and MYH11 c.4993C>T (p.Arg1665Cys)] are located in genes with "definitive" disease association (ClinGen). The remaining variants are in "potentially diagnostic" genes or genes with experimental evidence of disease association [NOTCH1 c.964G>A (p.Val322Met), COL4A5 c.953C>G (p.Pro318Arg), and PLOD3 c.833G>A (p.Gly278Asp)]. Russian patients with nssTAA without dissection examined in this study have ≥1 VUSs in six known genes of hereditary TAA (FBN1, COL3A1, MYH11, NOTCH1, COL4A5, or PLOD3). Experimental studies expanded genetic testing, and clinical examination of patients and first/second-degree relatives may shift VUSs to the pathogenic (benign) category or to a new class of rare "predisposing" low-penetrance variants causing the pathology if combined with other risk factors.

The UTHealth Houston Adult Cardiovascular Genomics Certificate Program: Efficacy and Impact on Healthcare Professionals

Background

The demand for genetic services has outpaced the availability of resources, challenging clinicians untrained in genetic integration into clinical decision-making. The UTHealth Adult Cardiovascular Genomics Certificate (CGC) program trains non-genetic healthcare professionals to recognize, assess, and refer patients with heritable cardiovascular diseases. This asynchronous online course includes 24 modules in three tiers of increasing complexity, using realistic clinical scenarios, interactive dialogues, quizzes, and tests to reinforce learning. We hypothesized that the CGC will increase genomic competencies in this underserved audience and encourage applying genomic concepts in clinical practice.

Methods

Required course evaluations include pre- and post-assessments, knowledge checks in each module, and surveys for module-specific feedback. After 6 months, longitudinal feedback surveys gathered data on the long-term impact of the course on clinical practice and conducted focused interviews with learners.

Results

The CGC was accredited in September 2022. Principal learners were nurses (24%), nurse practitioners (21%), physicians (16%), and physician assistants. Scores of 283 learners in paired pre- and post-assessments increased specific skills related to recognizing heritable diseases, understanding inheritance patterns, and interpreting genetic tests. Interviews highlighted the CGC's modular structure and linked resources as key strengths. Learners endorsed confidence to use genetic information in clinical practice, such as discussing genetic concepts and risks with patients and referring patients for genetic testing. Learners were highly likely to recommend the CGC to colleagues, citing its role in enhancing heritable disease awareness.

Conclusions

The CGC program effectively empowers non-genetic clinicians to master genomic competencies, fostering collaboration to prevent deaths from heritable cardiovascular diseases, and potentially transforming healthcare education and clinical practice.

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.

Early clinical outcomes and molecular smooth muscle cell phenotyping using a prophylactic aortic arch replacement strategy in Loeys-Dietz syndrome

OBJECTIVES

Patients with Loeys-Dietz syndrome demonstrate a heightened risk of distal thoracic aortic events after valve-sparing aortic root replacement. This study assesses the clinical risks and hemodynamic consequences of a prophylactic aortic arch replacement strategy in Loeys-Dietz syndrome and characterizes smooth muscle cell phenotype in Loeys-Dietz syndrome aneurysmal and normal-sized downstream aorta.

METHODS

Patients with genetically confirmed Loeys-Dietz syndrome (n = 8) underwent prophylactic aortic arch replacement during valve-sparing aortic root replacement. Four-dimensional flow magnetic resonance imaging studies were performed in 4 patients with Loeys-Dietz syndrome (valve-sparing aortic root replacement + arch) and compared with patients with contemporary Marfan syndrome (valve-sparing aortic root replacement only, n = 5) and control patients (without aortopathy, n = 5). Aortic tissues from 4 patients with Loeys-Dietz syndrome and 2 organ donors were processed for anatomically segmented single-cell RNA sequencing and histologic assessment.

RESULTS

Patients with Loeys-Dietz syndrome valve-sparing aortic root replacement + arch had no deaths, major morbidity, or aortic events in a median of 2 years follow-up. Four-dimensional magnetic resonance imaging demonstrated altered flow parameters in patients with postoperative aortopathy relative to controls, but no clear deleterious changes due to arch replacement. Integrated analysis of aortic single-cell RNA sequencing data (>49,000 cells) identified a continuum of abnormal smooth muscle cell phenotypic modulation in Loeys-Dietz syndrome defined by reduced contractility and enriched extracellular matrix synthesis, adhesion receptors, and transforming growth factor-beta signaling. These modulated smooth muscle cells populated the Loeys-Dietz syndrome tunica media with gradually reduced density from the overtly aneurysmal root to the nondilated arch.

CONCLUSIONS

Patients with Loeys-Dietz syndrome demonstrated excellent surgical outcomes without overt downstream flow or shear stress disturbances after concomitant valve-sparing aortic root replacement + arch operations. Abnormal smooth muscle cell-mediated aortic remodeling occurs within the normal diameter, clinically at-risk Loeys-Dietz syndrome arch segment. These initial clinical and pathophysiologic findings support concomitant arch replacement in Loeys-Dietz syndrome.

Histopathological Gap in Aortic Diseases: A Prospective Analysis

Aortic dissection (AD) is a critical cardiovascular condition with the potential for devastating consequences. This study evaluated the histological changes in the aorta wall in patients with AD and aortic aneurysm (AA) who received surgical aortic replacement. Histopathological data showed that modifications of the media layer (p = 0.0197), myxomatous aspect (p = 0.0001), and subendothelial layer degeneration (p = 0.0107) were more frequently seen in AA versus AD samples. Patients with AA were approximately twice as likely to develop histological changes than those with AD (p = 0.0037). Patients with moderate or severe medial degeneration had a higher chance of developing AD (p = 0.0001). Because the histopathological score proved to be a predictor of both in-hospital and overall mortality, its evaluation should become the standard of care in any patients who undergo aortic replacement. Individualized postoperative management might be influenced by the histopathological aspect of the aortic layer.

Development of Competency-based Online Genomic Medicine Training (COGENT)

The fields of genetics and genomics have greatly expanded across medicine through the development of new technologies that have revealed genetic contributions to a wide array of traits and diseases. Thus, the development of widely available educational resources for all healthcare providers is essential to ensure the timely and appropriate utilization of genetics and genomics patient care. In 2020, the National Human Genome Research Institute released a call for new proposals to develop accessible, sustainable online education for health providers. This paper describes the efforts of the six teams awarded to reach the goal of providing genetic and genomic training modules that are broadly available for busy clinicians.

Crucial Genes in Aortic Dissection Identified by Weighted Gene Coexpression Network Analysis

Background

Aortic dissection (AD) is a lethal vascular disease with high mortality and morbidity. Though AD clinical pathology is well understood, its molecular mechanisms remain unclear. Specifically, gene expression profiling helps illustrate the potential mechanism of aortic dissection in terms of gene regulation and its modification by risk factors. This study was aimed at identifying the genes and molecular mechanisms in aortic dissection through bioinformatics analysis.

Method

Nine patients with AD and 10 healthy controls were enrolled. The gene expression in peripheral mononuclear cells was profiled through next-generation RNA sequencing. Analyses including differential expressed gene (DEG) via DEGseq, weighted gene coexpression network (WGCNA), and VisANT were performed to identify crucial genes associated with AD. The Database for Annotation, Visualization, and Integrated Discovery (DAVID) was also utilized to analyze Gene Ontology (GO).

Results

DEG analysis revealed that 1,113 genes were associated with AD. Of these, 812 genes were markedly reduced, whereas 301 genes were highly expressed, in AD patients. DEGs were rich in certain categories such as MHC class II receptor activity, MHC class II protein complex, and immune response genes. Gene coexpression networks via WGCNA identified 3 gene hub modules, with one positively and 2 negatively correlated with AD, respectively. Specifically, module 37 was the most strongly positively correlated with AD with a correlation coefficient of 0.72. Within module 37, five hub genes (AGFG1, MCEMP1, IRAK3, KCNE1, and CLEC4D) displayed high connectivity and may have clinical significance in the pathogenesis of AD.

Conclusion

Our analysis provides the possible association of specific genes and gene modules for the involvement of the immune system in aortic dissection. AGFG1, MCEMP1, IRAK3, KCNE1, and CLEC4D in module M37 were highly connected and strongly linked with AD, suggesting that these genes may help understand the pathogenesis of aortic dissection.