肺動脈血栓内膜摘除術が奏効した慢性肺血栓塞栓症の1例

A Case Report of Pulmonary Thromboendarterectomy in a Patient with Chronic Pulmonary Thromboembolism

要旨　患者は70歳，女性，数年前から労作性呼吸困難を訴え，前医にて肺高血圧症と診断された．当院受診時には，安静時の呼吸困難を訴え，著明な低酸素血症を呈していた．各種の画像診断にて両側肺動脈に多発性の血栓を認め，慢性肺血栓塞栓症と診断した．血栓溶解療法を含めた内科的治療を施行したが効果なく，超低体温間欠的循環停止法による両側肺動脈血栓内膜摘除術を施行した．術後，肺動脈圧は著明に低下し，自覚症状は有意に改善した．肺動脈血栓内膜摘除術は慢性肺血栓塞栓症の唯一の根治的治療として考えられているが，手術死亡率も高いことから外科的治療例は少なく，一般的な治療の選択肢として普及していない．近年の血栓内膜摘除術の手術成績の向上，長期予後の改善に伴い，今後本治療が慢性肺血栓塞栓症の有効な治療の選択肢として認識され，その適応の検討が術前に適切に行われることが望まれる．

Summary

　A seventy-year-old female had experienced exertional dyspnea since two years before. She had difficulties in breathing at rest and, on admission blood gas analysis revealed severe hypoxemia. Imaging analyses showed that multiple thromoboemboli were present in the bilateral central pulmonary arteries. After a diagnosis of pulmonary hypertension caused by chronic pulmonary thromboembolism, medical treatments including thrombolytic therapy were started, but were ineffective for her symptoms, and pulmonary hemodynamics were not improved. She underwent a pulmonary thromboendarterectomy with intermittent circulatory arrest under hypothermia. Postoperatively, hemodynamic status and blood gas analysis showed marked improvement. Pulmonary thromboendarterectomy is a promising and potentially curative surgical procedure, but it has been only rarely performed in Japan, due to its technical difficulty. Recent advances in its surgical techniques and instruments can facilitate marked improvements in cardiopulmonary hemodynamics and prognosis, suggesting that the appropriate detemination of its surgical indication and preoperative evaluation will lead to further improvement in the prognosis of chronic pulmonary thromboembolism.