Congenital aortic stenosis secondary to dysplasia of congenital bicuspid aortic valves without commissural fusion.

The hearts of nine children with clinical evidence of congenital valve stenosis and a congenital bicuspid aortic valve were reviewed. Aortic stenosis was diagnosed on the basis of cardiac catheterization data in four patients, operative findings in two and auscultatory findings in three. The patients were 1 month to 9 years old; six were male and three female. In each patient the two commissures of the valve were free to the aortic wall. The cusps were thickened, rolled and redundant; microscopic studies revealed that they consisted of immature loose connective tissue consistent with a dysplastic or incompletely differentiated valve. The valve orifice was obstructed by the dysplastic cusps, and dysplastic changes rather than the commissural fusion were responsible for the observed aortic stenosis. These valves do not appear amenable to valvotomy because obstruction is due to the abnormal valve tissue. These findings may explain the occasional poor results of valvotomy in infants and children with congenital aortic valve stenosis.