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

Abstract

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.