Cross-Sectional Echocardiographic Assessment of Severity of Aortic Stenosis in Children
In a recent report we described the relationship of the maximum aortic cusp separation determined during long axis cross-sectional scanning of the aortic valve to the severity of aortic stenosis in adults. In order to utilize this measurement in children some correction for body size is obviously necessary. Because aortic size increases relative to body surface area as patient size decreases, routine correction of aortic valve orifice diameter for body surface area is misleading. We therefore elected to relate maximum aortic cusp separation (MACS) as an expression of aortic orifice size to the diameter of the aortic root (AO) at the valvular level. Thus the estimated aortic valve orifice diameter is expressed as a percentage of the aortic diameter. In this study MACS was determined in 14 children, ages 4 to 14 years, with valvular aortic stenosis and in 22 normal subjects. In normal subjects the aortic leaflets open freely with ventricular contraction and assume a position parallel and in close apposition to the walls of the aorta. In normals the maximum aortic cusp separation therefore should approach the aortic diameter. In the 22 normal subjects the MACS averaged 73% of the aortic diameter (range 63 to 92%). The data for the 14 children with aortic stenosis is listed in table I.