Massive aortic regurgitation by spontaneous rupture of a fibrous strand in a fenestrated aortic valve.

A very rare case of Marfan syndrome associated with acute aortic regurgitation due to rupture of a fibrous strand of a fenestrated aortic valve is presented. Although an aortic valve fenestration usually has no pathologic significance, its association with aortic annular dilatation plays an important role. Rupture of a myxomatously degenerated fibrous strand loaded with high tension from annular dilatation reducing the coaptation area of each cusp during diastole was the suspected cause of acute massive regurgitation by complete retroversion of the right coronary cusp. Rupture of a fibrous strand of a fenestrated aortic valve with a dilated annulus could result in acute massive aortic regurgitation, for which prompt surgical repair is mandatory.