術中所見で確定診断が得られた先天性一尖弁（unicommissural type）

Congenital Unicuspid Aortic Valve Diagnosed by Intraoperative Findings

先天性一尖弁は，成人心エコー検査施行例の0.02％のみにみられるまれな先天性大動脈弁疾患であるが1），手術が施行された大動脈弁狭窄症のうち4～6％が先天性一尖弁であったとの報告もされている2）．われわれは，先天性二尖弁の診断で手術を施行し，術中所見より先天性一尖弁の確定診断が得られた2例を経験したので，文献的考察を加え報告する．

A unicuspid aortic valve is an extremely rare congenital aortic valvular abnormality. We herein present 2 cases of unicuspid aortic valve diagnosed based on intraoperative findings. In case 1, a 75-year-old man was admitted to our hospital because of severe aortic regurgitation. We performed aortic valve replacement using a bioprosthetic valve, and a unicuspid aortic valve was definitively diagnosed according to the intraoperative findings. In case 2, a 54-year-old man developed dyspnea due to severe aortic stenosis. Aortic valve replacement using mechanical valve was performed, and we were able to diagnose unicuspid aortic valve intraoperatively. Achieving a preoperative definitive diagnosis of congenital unicuspid aortic valve by transthoracic echocardiography is reportedly difficult；however, transesophageal echocardiography may be effective for preoperative definitive diagnosis.