杉山 祐公 ¹, 桜川 浩¹, 徳弘 圭一¹, 田端 強志 ², 佐々木 健², 蛭田 啓之³, 亀田 典章³, 野池 博文¹, 東丸 貴信¹

Yuko SUGIYAMA ¹, Hiroshi SAKURAGAWA ¹, Keiichi TOKUHIRO ¹, Tsuyoshi TABATA², Ken SASAKI ², Nobuyuki HIRUTA³, Noriaki KAMEDA³, Hirofumi NOIKE¹, Takanobu TOMARU¹

¹東邦大学医療センター佐倉病院循環器センター, ²東邦大学医療センター佐倉病院生理機能検査部, ³東邦大学医療センター佐倉病院病理

¹Department of Cardiovascular Center, Toho University Medical Center Sakura Hospital , ²Department of Clinical Physiology, Toho University Medical Center Sakura Hospital, ³Department of Pathology, Toho University Medical Center Sakura Hospital

キーワード : quadricuspid aortic valve, aortic regurgitation, aortic stenosis, aortic valve replacement, echocardiogrphy

大動脈四尖弁は大動脈二尖弁と同様に大動脈弁機能不全の原因疾患となる先天性弁膜症である. 発生頻度は大動脈二尖弁より少なく稀な疾患である. 今回, 超音波検査により術前に大動脈弁四尖弁と診断し得た2 症例を経験したので報告する.症例1：63 歳, 男性, ペースメーカー植込み術を受けている. 労作時呼吸困難を自覚するようになり入院した. 心エコー検査の結果, 重度の大動脈弁逆流を認め, 左冠尖と無冠尖の間に副尖を有する大動脈四尖弁であった. 手術で四尖が確認され大動脈弁置換術(SJM 23 mm) を施行した. 組織像では軽度の線維増生と粘液変性が認められた. 症例2：58 歳,女性, 高血圧と気管支喘息のため近医で加療を受けていた. 労作時呼吸困難を自覚するようになり入院した. 心エコー検査の結果, 重度の大動脈弁逆流と大動脈弁狭窄の所見を認めたが, 大動脈弁形態は不明であった. 経食道心エコー検査を 施行し, 左冠尖と右冠尖の間に副尖を有する大動脈四尖弁と判明した. 手術で四尖が確認され大動脈弁置換術(SJM 17mm) を施行した. 組織像では高度の線維増生と石灰化が認められた. 心エコー検査で大動脈弁膜症の原因を検索する際には大動脈四尖弁の可能性も考慮に入れ慎重に観察する必要がある.

Quadricuspid aortic valve, like bicuspid aortic valve, is characterized by congenital malformation and resulting dysfunction of the aortic valve. This condition is rare, occurring less frequently than bicuspid aortic valve. We report two cases of quadricuspid aortic valve diagnosed preoperatively by echocardiography. Case 1: Quadricuspid aortic valve in a 63-year-old man who had previously received a permanent pacemaker. The patient presented dyspnea on exertion and was hospitalized. Echocardiography showed severe aortic regurgitation in a four-cuspid aortic valve with an accessory cusp between the left and non-coronary cusps. Quadricuspid aortic valve was confirmed on surgery, and the valve was replaced with a prosthesis (SJM 23 mm). Mild fibrosis and myxomatous degeneration were observed on histologic examination. Case 2: Quadricuspid aortic valve in a 58-year-old woman under treatment for hypertension and bronchial asthma. The patient presented dyspnea on exertion and was hospitalized. Transthoracic echocardiography showed severe aortic regurgitation and aortic stenosis, but the configuration of the aortic valve was unclear. Transesophageal echocardiography demonstrated a four-cuspid aortic valve with an accessory cusp between the left and right coronary cusps. Quadricuspid aortic valve was confirmed on surgery, and the valve　was replaced with a prosthesis (SJM 17 mm). Histologic examination showed calcification and extensive fibrosis. Quadricuspid　aortic valve should be considered when using echocardiography to investigate the cause of aortic valve disease.