Natural history of mild congenital aortic stenosis elucidated by serial hemodynamic studies

There is a paucity of information on the natural history of congenital aortic stenosis. This report analyzes serial clinical and hemodynamic data obtained prospectively from 15 initially asymptomatic children with congenital aortic stenosis. The first hemodynamic study was performed at an average age of 8.5, and the follow-up study at an average age of 15.1 years. The cardiac index was consistently normal in all patients. The peak pressure difference across the left ventricular outflow tract increased between initial and final studies in 12 of the 15 patients. The gradient ranged from 5 to 45 mm Hg (mean 26) during the first study, and from 15 to 81 mm Hg (mean 44) at follow-up examination. Severe obstruction (gradient > 50 mm Hg, normal cardiac output; or calculated aortic valve orifice <0.7 cm²/m² body surface area) developed in 6 of the 15 patients. In general, there was a poor correlation between the presence of symptoms, the electrocardiographic and radiographic findings and the severity of obstruction in any individual patient. The results of this study indicate that congenital aortic stenosis may be a progressive disorder, even early in life, in a significant fraction of patients presenting initially with mild obstruction.