Fused aortic valve without an elliptical-shaped systolic orifice in patients with severe aortic stenosis: cardiac computed tomography is useful for differentiation between bicuspid aortic valve with raphe and tricuspid aortic valve with commissural fusion

The objective is to determine cardiac computed tomography (CCT) features capable of differentiating between bicuspid aortic valve (BAV) and tricuspid aortic valve (TAV) in severe aortic stenosis (AS) patients with fused cusp and without elliptical-shaped systolic orifices. We retrospectively enrolled 53 patients who had severe AS with fused cusps and without an elliptical-shaped systolic orifice on CCT and who had undergone surgery. CCT features were analyzed using: 1) aortic valve findings including cusp size, cusp area, opening shape, midline calcification, fusion length, calcium volume score, and calcium grade; 2) diameters of ascending and descending aorta, and main pulmonary artery; and 3) rheumatic mitral valve findings. The variables were evaluated using univariate and multivariate logistic regression analyses. At surgery, 19 patients had BAV and 34 had TAV. CCT features including uneven cusp size, uneven cusp area, round-shaped systolic orifice, longer cusp fusion, and dilatation of ascending aorta were significantly associated with BAV (P < 0.05). In particular, fusion length (OR, 1.76; P = 0.001), uneven cusp area (OR, 10.46; P = 0.012), and midline calcification (OR, 0.08; P = 0.013) were strongly associated with BAV. CCT provides diagnostic clues that helps differentiate between BAV with raphe and TAV with commissural fusion in patients with severe AS. Accurate morphologic assessment of the aortic valve is important for treatment planning. It is difficult to differentiate BAV from TAV with a fused cusp. CCT provides diagnostic clues for the differentiation of BAV and TAV.