Morphology of the bicuspid aortic valve and elasticity of the adjacent aorta in children.

Bicuspid aortic valve (BAV) is a common congenital malformation with the known sequela of ascending aortic dilation. The morphology of the BAV and the elasticity of the adjacent ascending aorta appear to influence the outcome. We prospectively examined 48 pediatric patients with an isolated, native BAV for the morphology and size of the aortic valve, aortic root, sinotubular junction, and ascending aorta and their elasticity indexes. A cohort of 48 matching subjects with tricuspid aortic valves was investigated as controls. A comparison of the aortic valve subtypes showed normal-size aortic dimensions in the tricuspid aortic valves. In contrast, in the BAVs, the ascending aorta and aortic valve itself tended to dilate with age and aortic elasticity deteriorated. In the BAVs, the stiffness was significantly greater (4.43 ± 1.82 vs 3.43 ± 0.81 in the tricuspid aortic valves; p = 0.001). The distensibility indexes decreased inversely in the BAVs (6.57 ± 2.83 vs 7.84 ± 2.04 cm(2) × dynes(-1) × 10(-6), p = 0.013; and 53.5 ± 26.0 versus 64.3 ± 17.9 kPa(-1) × 10(-3), p = 0.020). The anteroposterior-oriented phenotype of BAVs showed significantly stiffer and less distensible elasticity even after correction for congenital valve dysfunction, which was more frequent in the left-right-oriented phenotype. In conclusion, the morphology of the BAV seems to play a major role in the outcome of BAV disease, although the left-right phenotype is more prone to congenital valve dysfunction, the anteroposterior phenotype showed worse elasticity quality.