肺内右左シャントを有する門脈肺高血圧症の1例

A Case of Portopulmonary Hypertension with the Right-to-left Shunt

要旨　症例は73歳女性．自己免疫性肝炎にて無治療経過観察中であった．約5年前より労作時呼吸困難が出現し，増悪傾向にあった．当科受診時には低酸素血症および腹部エコー上肝硬変の所見を認めた．肺血流シンチグラフィおよびコントラスト心臓超音波検査にて右左シャントの存在を認め，肝肺症候群の可能性を考慮したが，心臓超音波検査では推定右室収縮期圧60mmHgと肺高血圧の所見であった．右心カテーテル検査では肺動脈圧の上昇と肺血管抵抗の上昇を認め，門脈肺高血圧症と診断した．治療として，アンブリセンタンを選択．自覚症状，心エコー所見，6分間歩行距離すべてにおいて改善を認めた．副作用は軽度の皮疹，頭痛などで，肝機能障害の悪化はなかった．アンブリセンタンは，門脈肺高血圧症に対して安全で有効である可能性が考えられた．

　A 73-year-old female visited our hospital because of progressive dyspnea on exertion. She had autoimmune hepatitis but she did not receive steroid therapy for her request. She had a feeling of dyspnea from five years ago, and her symptom gradually worsened. She was never a smoker. When she visited our hospital, PaO₂ level was 60.3torr and PaCO₂ level was 35.5torr in room air. There was evidence of hepatic cirrhosis and splenomegaly in abdominal echography, but no evidence of ascites. Additionally, the right-to-left shunt rate by (99m) Tc-MAA scanning was found in 16.7%. Therefore we considered the possibility of hepatopulmonary syndrome. However, estimated right ventricular systolic pressure level by echocardiogram showed 60torr, and right heart catheterization confirmed elevation of pulmonary vascular resistance and pulmonary arterial pressure. We finally diagnosed her as having portpulmonary hypertension. By treatment using Ambrisentan, the patient's clinical status improved in its symptoms, echocardiographic findings, and six minutes walk distance. The side effect by Ambrisentan showed mild eruption and headache, but did not cause an aggravation of liver function. This case report illustrates one possible safety neasure and the effect in Ambrisentan for portopulmonary hypertension.