[Aortic Regurgitation due to Rupture of a Fibrous Strand in Fenestrated Aortic Valve:Report of a Case].

Fenestration of the aortic valve cusps rarely causes aortic regurgitation. A 54-year-old woman was diagnosed with aortic regurgitation secondary to a ruptured fibrous strand in a fenestrated aortic valve cusp. Diastolic murmur was pointed out during health checkup five months earlier, and transthoracic echocardiography revealed severe aortic valve regurgitation with a mobile mass attached to the aortic valve cusp. The patient underwent aortic valve replacement. Intraoperatively, we observed a ruptured fibrous strand attached to the non-coronary cusp and cusp laceration, both of which caused severe aortic regurgitation. Histopathological examination of the resected specimen showed myxomatous degeneration. The patient's postoperative course was uneventful, and she was discharged in a stable condition on postoperative day 14.