Acute aortic regurgitation due to local avulsion of the aortic valve commissure.

A 69-year-old man was transferred to our hospital because of sudden onset precordial pain and dyspnea. Transesophageal echocardiography revealed massive aortic regurgitation, diastolic separation of the closure line of the aortic cusps and prolapsing motion of the cusps during diastolic toward the left ventricular outflow tract. Aortic valve replacement was successfully performed. During the operation, we found a commissure between the left coronary cusp and the non-coronary cusp that had avulsed from the aortic wall and prolapsed into the left ventricular outflow tract. Valvular cusps were excised and replaced with a mechanical prosthesis. The postoperative course was uneventful and the patient was discharged from the hospital, 25 days after his operation. The histopathological examination showed fibrosis, hyalinosis of the avulsed commissure, and mucoid degeneration of the valve. There was no evidence of pathologic changes, such as aortitis, infective endocarditis, or specific connective tissue disorders.