Spontaneous rupture of bicuspid aortic valve. An unusual cause of aortic insufficiency.

This report documents the clinicopathologic correlation between pure aortic regurgitation and an exceptional form of congenitally bicuspid aortic valve. The patient was known for many years to have mild aortic insufficiency. His condition suddenly deteriorated, with signs of an aggravated aortic regurgitation. Infectious endocarditis was considered, but the diagnosis was never established. Surgery revealed an exceptional form of a bicuspid aortic valve in which the conjoined cusp had prolapsed, due to rupture of a fibrous strand which previously had anchored the free rim of the cusp to the inner wall of the aorta. There were no signs of infectious endocarditis. It is suggested that spontaneous rupture of the cord caused the sudden aggravation of aortic regurgitation.