大動脈四尖弁による大動脈弁閉鎖不全症の1例

A Case of Quadricuspid Aortic Valve with Aortic Regurgitation

要旨　症例は47歳，男性．主訴は夜間呼吸困難．心エコー検査，心臓カテーテル検査で重度の大動脈弁閉鎖不全症を認め，大動脈弁置換術を施行した．大動脈弁は四尖で，無冠尖がほぼ均等に2つに分かれる形で余剰な交連が存在した．その2つの弁尖は癒合し，rapheがそれらを分けていた．大動脈四尖弁は非常に稀な疾患で，その発生頻度は剖検例で0.008〜0.033%と報告されている．閉鎖不全症が問題となることが多く，手術適応となる率も高い．手術は大動脈弁置換術が行われることが多いが，近年大動脈弁形成術の報告もみられる．手術適応でない場合も，弁機能異常が進行する可能性も高いため，注意深い経過観察が必要である．

A 47-year-old man was admitted to our hospital for nocturnal dyspnea. Transthoracic echocardiography and cardiac catheterization demonstrated severe aortic regurgitation for which aortic valve replacement was performed. The aortic valve was quadricuspid, and a supernumerary commissure existed in which the noncoronary cusp was divided into two equal portions. Fusion of the two cusps was evident and a raphe was present between them. Quadricuspid aortic valve is a very rare malformation with an estimated incidence of 0.008-0.033% on autopsy studies. Patients with a quadricuspid aortic valve are predisposed to aortic valve regurgitation, and surgical treatment is required in many cases. Aortic valve replacement is often performed, but in recent years several cases of aortic valvuloplasty have been reported. Patients with quadricuspid aortic valve who are not indicated for surgery require close follow-up for the high likelihood of valve dysfunction progression.