33歳まで生存し得た肺動脈狭窄を伴わない両大血管右室起始症の1剖検例

A rare adult case with double-outlet right ventricle without pulmonary stenosis:An autopsy case

　症例は死亡時33歳の女性。小学校時に心雑音を指摘され，その後，呼吸困難感等はあったが放置。25歳時に初めて心精査を当科で受けた。現症では体重31kg，身長148cmと小柄。チアノーゼ，顔面浮腫，肝腫大を認め，胸骨左縁で駆出性収縮期雑音と逆流性拡張期雑音を聴取した。胸部X線では左第2弓の突出を認め，心胸郭比は58％。心電図は右軸偏位と両室肥大を呈した。心血管造影等で，両大血管右室起始症（DORV）と診断された。その後，内科的に経過観察されたが，8年後に死亡した。剖検心では，大動脈と肺動脈の位置関係はほぼ正常で，ともに完全に右室から起始し，半月弁と僧帽弁の線維性連続はなかった（両側円錐）。心室中隔欠損口は大動脈弁下で，肺動脈狭窄は認めなかった。本例は典型的DORVであり，動脈管開存と管前性大動脈縮窄を伴っていた。文献的に，DORV成人例の報告はまれで，とくに肺動脈狭窄を伴わないDORV成人例は，我々が調べ得た限りでは皆無であった。

Double outlet right ventricle (DORV) is a rare cardiac malformation especially in adulthood. We report a woman with DORV who survived to the age of 33 years. She had not been seriously limited, before she visited our hospital for cardiac evaluation at the age of 25 years. She was cyanotic, and had clubbing of fingers and toes and facial edema. Ho-losystolic murmur and diastolic regurgitant murmur were audible along the left sternal border. Chest X-ray showed cardiomegaly and enlarged pulmonary truncks. Electrocardiography showed right axis de-viation and biventricular hypertrophy. Laboratory examination revealed polycythemia (Hb: 22.4 g/d/), increased levels of hepatic enzymes due to conges-tive liver and marked hypoxemia (Pao₂: 40 mmHg), Diagnosis of DORV was made with cardioangiogra-phy. Surgical repair was not indicated. Thereafter, she experienced recu rent heart failure which pro-gressed gradually. She died probably of ventricular arrhythmia at the age of 33 years. At autopsy, the heart showed dilatation of the right atrium and ventricle, and hypertrophy of the bilateral ventricles. Both the pulmonary artery without stenosis and the aorta originated completely from the right ven-tricle, which were almost normally positioned with bilateral conus. Large ventricular septa] defect was found at the subaortic portion. Patent ductus arte-riosus and preductal aortic coarctation co-existed.To our knowledge, few cases with DORV who survived over 30 years have been reported, and they all manifested pulmonary stenosis. The present case is a very rare DORV that survived over 30 years without the complication of pulmonary stenosis. It is speculated that, in the present case, combina-tion of the patent ductus artericsus and the preduc-tal aortic coarctation decreased pulmonary blood flow and reduced hypertensive changes of the pul-monary vasculature, and that this is one of the factors contributing most to longevity without sur-gical repair or palliation.