Aortic Dilatation in Patients With Bicuspid Aortic Valve

Epigenetic Biomarkers in Thoracic Aortic Aneurysm, Dissection, and Bicuspid Aortopathy: A Comprehensive Review

Thoracic aortic disease (TAD) encompasses a spectrum of life-threatening conditions, including thoracic aortic aneurysm (TAA), acute type A aortic dissection (ATAAD), and bicuspid aortic valve (BAV)-associated aortopathy. While genetic mutations are well-documented contributors, emerging evidence highlights epigenetic mechanisms as critical regulators of TAD pathogenesis. This comprehensive review explores the role of epigenetic modifications-DNA methylation, histone modifications, and microRNA (miRNA) regulation-in vascular remodeling, extracellular matrix degradation, and endothelial dysfunction. Aberrant DNA methylation patterns have been implicated in TAA and ATAAD, influencing genes responsible for vascular integrity and inflammation. Histone modifications modulate smooth muscle cell phenotype switching, impacting aneurysm progression. Additionally, dysregulated miRNA expression contributes to endothelial barrier disruption and extracellular matrix remodeling, presenting novel avenues for biomarker discovery. The reversibility of epigenetic modifications offers a promising therapeutic target, with pharmacological agents such as histone deacetylase inhibitors and miRNA-based therapies showing potential in preclinical models. This review underscores the translational potential of epigenetic biomarkers for early disease detection, risk stratification, and precision medicine approaches. Further research is needed to integrate these findings into clinical practice, paving the way for innovative diagnostic and therapeutic strategies in TAD management.

Role of miRNAs in Regulating Ascending Aortic Dilation in Bicuspid Aortic Valve Patients Operated for Aortic Stenosis

Deregulation of micro-RNAs (miRNAs) may contribute to mechanisms of injury in the bicuspid aortic valve (BAV). Our objective was to investigate the expression of miRNAs in aortic tissue from patients who underwent aortic valve replacement for aortic stenosis and its relationship with aortic dilatation. The study included 78 patients, 40 with bicuspid aortic valve (BAV) and 38 with tricuspid aortic valve (TAV). The expression of miRNA-17-5p, hsa-let-7e, and miRNA-196a-5p in human aortic tissue was evaluated by a reverse transcriptase polymerase chain reaction (RT-qPCR). Comparative analysis between patients with BAV and controls with TAV explored the association between the miRNAs and aortic dilatation (AD), calcification, valve dysfunction, and stenosis. The results showed that the expression levels of miRNA-Let-7e-5p and miRNA-196-5p were mostly increased in patients with BAV and aortic dilatation (p = 0.01 and p = 0.01), respectively. In contrast, the levels of miRNA-17a-5p (p < 0.20) were lower but without a statistically significant difference. The downregulation of miRNA-17a-5p and the upregulation of miR-Let-7e-5p and miR-196-5p were related to an increased risk of AD risk. Subjects with BAVs with or without double aortic lesions had higher expression levels of Let-7e-5p and miRNA-17a-5p vs. TAV. In all patients, we found an inverse correlation of MiRNA-196-5p with High-Density Lipoprotein-Cholesterol (HDL-C) and indexed valvular area. In subjects with a higher expression of miRNA196, lower levels of HDL-C correlation (r2) [r2 0.27 (p = 0.02)] and a lower indexed valvular area [r2 0.28 (p = 0.05)] were observed. In the specific analysis for each patient group, it was found that in control subjects with tricuspid aortic valve (TAV), miRNA-196-5p had a positive correlation with valvular calcification (r2 = 0.60, p = 0.02). Deregulation of miRNAs in the aortic tissue of a BAV may influence valvular stenosis, dysfunction, and concomitant aortic dilation. This information could help to define potential therapeutic target strategies to improve the prognosis and treatment of BAV.

Diagnostic value of selected fetal echocardiographic parameters in the prenatally suspected bicuspid aortic valve

OBJECTIVE

To explore the diagnostic value of crucial parameters of echocardiography for fetal bicuspid aortic valve (BAV) and improve diagnostic accuracy.

METHODS

Fetuses with a prenatal suspected diagnosis of BAV were followed, and confirmed and misdiagnosed cases were obtained. Prenatal echocardiography was reviewed and analyzed. ROC curves were plotted to evaluate the diagnostic capabilities of different echo signs.

RESULTS

14 cases were confirmed, and 7 patients were misdiagnosed. Some abnormal ultrasound signs were observed in both groups, including direct ultrasound signs of the aortic valve: Two commissures and a "fish-mouth" opening; Thickening, hyperechogenicity, or the presence of a raphe; Restricted motion or opening; Eccentric or a-linear valve leaflet closure line and indirect ultrasound signs: Increased supra-aortic valve velocity; Post-stenotic widening of the ascending aorta. The combination of "Increased supra-aortic valve velocity" and "Two commissures and a 'fish-mouth' opening" had the highest AUC (AUC: 0.893, 95%CI: 0.752-1.000, Sensitivity: 0.786, Specificity: 1.000).

CONCLUSIONS

We first found that the combination of "Increased supra-aortic valve velocity" and "Two commissures and a 'fish-mouth' opening" had the best diagnostic capability and could reduce the rate of misdiagnosis. Fetuses with BAV should be followed up prenatally for the aortic valve and ascending aorta as they progressively deteriorate with gestational age.

Effect of aortic valve phenotype and sex on aorta dilation in patients with aortic stenosis

BACKGROUND

Bicuspid aortic valve (BAV) is often associated with a concomitant aortopathy. However, few studies have evaluated the effect of the aortic valve (AV) phenotype on the rate of dilation of the aorta. This study aimed to compare the progression rate of aorta dimensions according to AV phenotype (BAV vs tricuspid AV (TAV)), fusion type and sex in patients with aortic stenosis (AS).

METHODS

310 patients with AS (224 TAV and 86 BAV) recruited in the Metabolic Determinants of the Progression of Aortic Stenosis study (PROGRESSA, NCT01679431) were included in this analysis. Doppler echocardiography was performed annually to assess AS severity and measure ascending aorta (AA) dimensions. Baseline and last follow-up visit measurements were used to assess the annualised change.

RESULTS

Median AA annualised change was larger in BAV versus TAV (0.33±0.65 mm/year vs 0.21±0.56 mm/year, p=0.04). In the whole cohort, BAV phenotype and higher low-density lipoprotein (LDL) levels were significantly associated with fast progression of AA dilation in univariate analysis (OR 1.80, 95% CI 1.08 to 2.98, p=0.02; 1.37, 95% CI 1.04 to 1.80, p=0.03, respectively). AA dilation rate did not vary according to the BAV subtype (p=0.142). Predictors of AA progression rate were different between valve phenotypes, with higher apolipoprotein B/apolipoprotein A-I ratio, higher baseline peak aortic jet velocity (Vpeak) and smaller baseline AA diameter in the TAV cohort (all p<0.05) versus absence of hypertension, higher LDL levels and smaller baseline AA diameter in the BAV cohort (all p<0.02). In men, higher baseline Vpeak and smaller baseline AA (p<0.001) were independently associated with increased annualised AA dilation, while in women, higher LDL levels (p=0.026) were independently associated with faster AA dilation.

CONCLUSION

This study suggests that BAV is associated with faster dilation of the AA. Predictors of AA dilation are different between valve phenotype and sex, with higher LDL levels being associated with faster AA dilation in BAV.

From Biomechanical Properties to Morphological Variations: Exploring the Interplay between Aortic Valve Cuspidity and Ascending Aortic Aneurysm

Background: This research explores the biomechanical and structural characteristics of ascending thoracic aortic aneurysms (ATAAs), focusing on the differences between bicuspid aortic valve aneurysms (BAV-As) and tricuspid aortic valve aneurysms (TAV-As) with non-dilated aortas to identify specific traits of ATAAs. Methods: Clinical characteristics, laboratory indices, and imaging data from 26 adult patients operated on for aneurysms (BAV-A: n = 12; TAV-A: n = 14) and 13 controls were analyzed. Biomechanical parameters (maximal aortic diameter, strain, and stress) and structural analyses (collagen fiber organization, density, fragmentation, adipocyte deposits, and immune cell infiltration) were assessed. Results: Significant differences in biomechanical parameters were observed. Median maximal strain was 40.0% (control), 63.4% (BAV-A), and 45.3% (TAV-A); median maximal stress was 0.59 MPa (control), 0.78 MPa (BAV-A), and 0.48 MPa (TAV-A). BAV-A showed higher tangential modulus and smaller diameter, with substantial collagen fragmentation (p < 0.001 vs. TAV and controls). TAV-A exhibited increased collagen density (p = 0.025), thickening between media and adventitia layers, and disorganized fibers (p = 0.036). BAV-A patients had elevated adipocyte deposits and immune cell infiltration. Conclusions: This study highlights distinct pathological profiles associated with different valve anatomies. BAV-A is characterized by smaller diameters, higher biomechanical stress, and significant collagen deterioration, underscoring the necessity for tailored clinical strategies for effective management of thoracic aortic aneurysm.

Aortic Valve Dysfunction and Aortopathy Based on the Presence of Raphe in Patients with Bicuspid Aortic Valve Disease

(1) Background: To identify the association between the presence or absence of a raphe and aortic valve dysfunction, as well as the presence of aortopathy in patients with a bicuspid aortic valve (BAV); (2) Methods: This retrospective study enrolled 312 participants (mean (SD) age, 52.7 (14.3) years; 227 men (72.8%)) with BAV. The BAVs were divided into those with the presence (raphe+) or absence (raphe-) of a raphe. Valvular function was classified as normal, aortic regurgitation (AR), or aortic stenosis (AS) using TTE. The pattern of BAV aortopathy was determined by the presence of dilatation at the sinus of Valsalva and the middle ascending aorta using CCT; (3) Results: BAVs with raphe+ had a higher prevalence of AR (148 (79.5%) vs. 48 (37.8%), p < 0.001), but a lower prevalence of AS (90 (48.6%) vs. 99 (78.0%), p < 0.001) compared with those with raphe-. The types of BAV aortopathy were significantly different (p = 0.021) according to those with BAV-raphe+ and BAV-raphe-; (4) Conclusions: The presence of a raphe was significantly associated with a higher prevalence of AR, but a lower prevalence of AS and combined dilatation of the aortic root and middle ascending aorta. The presence of a raphe was an independent determinant of AR.

Feasibility of Wave Intensity Analysis from 4D Cardiovascular Magnetic Resonance Imaging Data

Congenital heart defects (CHD) introduce haemodynamic changes; e.g., bicuspid aortic valve (BAV) presents a turbulent helical flow, which activates aortic pathological processes. Flow quantification is crucial for diagnostics and to plan corrective strategies. Multiple imaging modalities exist, with phase contrast magnetic resonance imaging (PC-MRI) being the current gold standard; however, multiple predetermined site measurements may be required, while 4D MRI allows for measurements of area (A) and velocity (U) in all spatial dimensions, acquiring a single volume and enabling a retrospective analysis at multiple locations. We assessed the feasibility of gathering hemodynamic insight into aortic hemodynamics by means of wave intensity analysis (WIA) derived from 4D MRI. Data were collected in n = 12 BAV patients and n = 7 healthy controls. Following data acquisition, WIA was successfully derived at three planes (ascending, thoracic and descending aorta) in all cases. The values of wave speed were physiological and, while the small sample limited any clinical interpretation of the results, the study shows the possibility of studying wave travel and wave reflection based on 4D MRI. Below, we demonstrate for the first time the feasibility of deriving wave intensity analysis from 4D flow data and open the door to research applications in different cardiovascular scenarios.

Plasma Exosomal Mir-423-5p Is Involved in the Occurrence and Development of Bicuspid Aortopathy via TGF-β/SMAD2 Pathway

OBJECTIVES

Patients with bicuspid aortic valve (BAV) are at increased risk for ascending aortic dilation (AAD). Our study was aimed at systemically analyzing the expression profile and mechanism of circulating plasma exosomal microRNAs (miRNAs) related to BAV and AAD.

METHODS

We isolated plasma exosomes from BAV patients (n=19), BAV patients with AAD (BAVAD, n=26), and healthy tricuspid aortic valve individuals with low cardiovascular risk (TAVnon, n=16). We applied a small RNA sequencing approach to identify the specific plasma exosomal miRNAs associated with BAV (n=8) and BAVAD (n=10) patients compared with healthy TAVnon (n=6) individuals. The candidate differentially expressed (DE) miRNAs were selected and validated by RT-qPCR in the remaining samples. GO and KEGG pathway enrichment analyses were performed to illustrate the functions of target genes. Western blot analysis and luciferase reporter assay were conducted in human aortic vascular smooth muscle cells (VSMCs) to verify the results of target gene prediction in vitro. Results: The expression levels of three up-regulated (miR-151a-3p, miR-423-5p, and miR-361-3p) and two down-regulated (miR-16-5p and miR-15a-5p) exosomal miRNAs were significantly altered in BAV disease. Additionally, miR-423-5p could be functionally involved in the occurrence and development of BAV and its complication BAVAD by regulating TGF-β signaling. miR-423-5p could target to SMAD2 and decreased the protein levels of SMAD2 and P-SMAD2.

CONCLUSION

Plasma exosomal miR-423-5p regulated TGF-β signaling by targeting SMAD2, thus exerting functions in the occurrence and development of BAV disease and its complication bicuspid aortopathy.