Abstract 19684: Abnormal Aortic Wall Properties in Children with Isolated Bicuspid Aortic Valve

Abstract

Introduction: Abnormal aortic wall properties have been reported in patients with isolated bicuspid aortic valve (IBAV) even in the absence of significant aortic stenosis or regurgitation. Hypothesis: We sought to assess aortic distensibility (DIS) and stiffness index (SI) in children with IBAV compared to age group-matched subjects with normal tricuspid aortic valves (TAV) and to determine whether these abnormalities in the aortic wall properties correlate with bicuspid valve morphology or left ventricular systolic or diastolic function. Methods: Children ages 8-18 years with an IBAV and age group-matched controls with a TAV were prospectively enrolled. Subjects with greater than mild stenosis or mild regurgitation were excluded. Using echo, aortic valve morphology, aortic root (AoR) and ascending aorta (AAo) diameters and z-scores were determined. Left ventricular shortening fraction (LVSF), DIS and SI were measured using M-mode echo. Diastolic function was determined using mitral valve septal E/Ea. Blood pressure (BP) was measured at the time of echo. Results: Nineteen had IBAV and 17 had TAV. There were no significant differences in age, weight, height or BP between the two groups. In the IBAV group, 11 had right-left type (R/L) and 8 had right-non type (R/N). There was no significant difference in AoR z-scores between groups. The IBAV group had larger AAo z-scores (2.48±1.9 vs. -0.02±0.98, p<0.0001), decreased DIS (9.6±4 vs. 12.3±3.1 cm2 dynes-1 x 10-6, p<0.05) and increased SI (21.4±9.2 vs. 14.4±3.8, p=0.007) compared to the TAV group. There were no differences in these variables between the R/L or R/N subgroups. No correlation was seen between aortic wall properties and ventricular function in the IBAV group. By multivariate regression, presence of an IBAV (coefficient = -2.4, p=0.03), LVSF (coefficient = -0.35, p=0.01) and age-adjusted systolic BP (coefficient = -0.13, p=0.03) were independently associated with DIS. Similarly, presence of an IBAV (coefficient = 6.7, p=0.005) and age (coefficient=0.85, p=0.02) were independently associated with SI. Conclusions: Children with IBAV have decreased DIS and SI even without hemodynamic abnormalities. Long-term studies to determine the impact of these findings on cardiovascular risk are needed.