Bicuspid aortic valve phenotyping by cardiac computed tomography and its clinical implications

OBJECTIVES: A new nomenclature and classification of the bicuspid aortic valve (BAV) was proposed. However, phenotyping using echocardiography remains limited in accuracy. This study aimed to evaluate the utility of cardiac CT for BAV phenotyping and its association with clinical relevance. MATERIALS AND METHODS: Four hundred eighteen BAV patients who underwent both echocardiography and cardiac CT within 3 months were analyzed. BAV was classified as fused, 2-sinus, or partial-fusion type. We investigated the association between the CT-derived BAV phenotype and types of BAV dysfunction and aortopathy. RESULTS: CT-derived BAV phenotypes showed 58.6% concordance with echocardiography-based phenotypes. Fifty patients (12.0%) had a partial-fusion type based on echocardiography, but 124 patients (29.7%) had this type based on CT. CT-derived fused and 2-sinus type had a higher incidence of significant aortic stenosis than the other CT-based phenotypes adjusted odds ratio (aOR):1.21, 95% CI: 1.12-1.31, p < 0.001; aOR: 1.14, 95% CI: 1.05-1.23, p = 0.002, respectively. Partial-fusion type was associated with a higher incidence of significant aortic regurgitation (aOR: 1.50, 95% CI: 1.38-1.63, p < 0.001) and lower incidence of ascending-type aortopathy (aOR:0.88, 95% CI: 0.80-0.97, p = 0.008). In the 2-sinus BAV subgroup, a latero-lateral opening was more significantly associated with all types of aortopathy than the antero-posterior opening type (aOR:1.23, 95% CI: 1.05-1.43, p = 0.011). CONCLUSIONS: Cardiac CT provides accurate information for BAV phenotype using the new nomenclature system. CT-derived BAV phenotyping is associated with types of BAV dysfunction and aortopathy and may therefore be useful for risk prediction in patients with a BAV. KEY POINTS: Question Echocardiographic phenotyping of BAV is limited in accuracy. This study evaluated the utility and clinical relevance of CT-based BAV phenotyping. Findings CT and echocardiography showed 58.6% agreement in BAV phenotyping. CT identified more partial-fusion types and was significantly associated with valve dysfunction and aortic disease. Clinical relevance Cardiac CT provides accurate BAV phenotyping using the new nomenclature. CT-derived phenotype correlates with BAV dysfunction and aortic disease, suggesting its potential role in risk stratification and personalized management of patients with BAV.