Pathogenetic significance of myxomatous degeneration in fenestration-related massive aortic regurgitation.

Background: Aortic valvular regurgitation has several mechanisms and the present study investigated its clinicopathological correlations with aortic valve fenestration.

Methods And Results: Six male patients with massive regurgitation and enlarged fenestrations or ruptured fenestrated fibrous cords underwent aortic valve replacement. The clinicopathological features showed many similarities. Four cases had family histories of aortic regurgitation. All six patients showed moderate to severe myxomatous degeneration of the aortic valve and enlargement of aortic annulus. Four patients had 1-2 ruptured fibrous cords, located at the right coronary cusp. Echocardiographic examinations showed an abnormal fibrous cord attached to the prolapsing cusp in 3 cases with ruptured fenestrated valve and detailed examination by transesophageal echocardiography showed an intact fenestrated fibrous cord at the commissure in 1 case.

Conclusion: Extensively fenestrated cusps with an enlarged aortic annulus because of myxomatous degeneration can cause chronic regurgitation or sudden deterioration after rupture of the fibrous cord. There is an increasing incidence of fenestration-related aortic regurgitation in the Japanese population. An important pathogenetic factor in male patients is myxomatous degeneration of the aortic cusp and annulus.