Della Corte, Alessandro

BACKGROUND: Bicuspid aortic valve (BAV) is a frequent congenital heart defect with a high heritability. Despite this, only a limited number of genes have been associated with the disease, and the molecular mechanisms remain unexplained in most cases. This study aimed to further understand the genetic architecture of BAV. METHODS: A genome-wide association study meta-analysis including 9631 cases among 65 677 participants was performed. Genes were prioritized using transcriptomic analyses based on RNA sequencing in relevant tissues, including human fetal and adult aortic valves. The impact of the knockdown or knockout of 4 candidate genes on cardiac development was verified in zebrafish. A polygenic risk score was developed, its association with BAV was evaluated in an independent cohort, and its association with a wide range of phenotypes (n=976) was evaluated in UK Biobank (n=355 618 individuals). RESULTS: Thirty-six genomic loci were identified, including 32 that were not described previously. Among the prioritized genes, KANK2 and ERBB4 were identified as potentially causal through transcriptomic analyses, colocalization, and Mendelian randomization based on gene expression in human aortic valves (n=484), whereas PRDM6 and STRN were prioritized using similar analyses from aortic (n=326) and left ventricular tissues (n=326), respectively. Targeting 4 candidate genes ( WNT4 , LEF1 , STRN , and KANK2 ) in zebrafish led to disruption in cardiac development. A polygenic risk score was associated with an odds ratio of 2.07 (95% CI, 1.90–2.25; P =5.43×10 -62 ) per SD for BAV and significantly associated with thoracic aortic aneurysm and atrial fibrillation in UK Biobank. CONCLUSIONS: This study supports a significant polygenic contribution to BAV, where the combination of multiple common variants in genes involved in heart morphogenesis disrupts aortic valve development.

Abstract Severe aortic valve regurgitation, if not timely treated, can significantly impact patients’ survival both for tricuspid aortic valve and bicuspid aortic valve patients, with the latter being significantly younger. Increased understanding of the root anatomy and its physiology has opened the way to techniques of aortic valve repair surgery. The techniques mainly relate to re-establishing a correct root and annular geometry and eliminating leaflet prolapse. These techniques are applied both in the presence of a dilated and normal root and are equally valid for tricuspid or bicuspid valve. Techniques for repairing a bicuspid valve might vary depending on the different valve phenotypes. Medium and long-term results appear favourable and potentially superior to those of prosthetic replacement in terms of valve-related complications and quality of life. Optimal surgical treatment, especially in younger and selected patients, should aim to avoid aortic valve replacement and its related complications.

Abstract OBJECTIVES The prevalence and aetiology of acute aortic dissection type A (AADA) in patients ≤30 years is unknown. The aims of this clinical study were to determine the prevalence and potential aetiology of AADA in surgically treated patients ≤30 years and to evaluate the respective postoperative outcomes in this selective group of patients in a large multicentre study. METHODS Retrospective data collection was performed at 16 participating international aortic institutions. All patients ≤30 years at the time of dissection onset were included. The postoperative results were analysed with regard to connective tissue disease (CTD). RESULTS The overall prevalence of AADA ≤30 years was 1.8% (139 out of 7914 patients), including 51 (36.7%) patients who were retrospectively diagnosed with CTD. Cumulative postoperative mortality was 8.6%, 2.2% and 1.4%. Actuarial survival was 80% at 10 years postoperatively. Non-CTD patients (n = 88) had a significantly higher incidence of arterial hypertension (46.6% vs 9.8%; P < 0.001) while AADA affected the aortic root (P < 0.001) and arch (P = 0.029) significantly more often in the CTD group. A positive family history of aortic disease was present in 9.4% of the study cohort (n = 13). CONCLUSIONS The prevalence of AADA in surgically treated patients ≤30 years is <2% with CTD and arterial hypertension as the 2 most prevalent triggers of AADA. Open surgery may be performed with good early results and excellent mid- to long-term outcomes.

Abstract This International Consensus Classification and Nomenclature for the congenital bicuspid aortic valve condition recognizes 3 types of bicuspid valves: 1. The fused type (right-left cusp fusion, right-non-coronary cusp fusion and left-non-coronary cusp fusion phenotypes); 2. The 2-sinus type (latero-lateral and antero-posterior phenotypes); and 3. The partial-fusion (forme fruste) type. The presence of raphe and the symmetry of the fused type phenotypes are critical aspects to describe. The International Consensus also recognizes 3 types of bicuspid valve-associated aortopathy: 1. The ascending phenotype; 2. The root phenotype; and 3. Extended phenotypes.