腎静脈直上から右心室まで達し，その先端が右房と右室の間で振り子様運動を繰り返す巨大な深部静脈血栓が認められた１例

A Large Thrombus in the Inferior Vena Cava,with its Stalk Adherent to the Proximal Portion of the Renal Vein and its Head Swaying like a Pendulum between the Right Atrium and the Right Ventricle：A case report

患者は48歳の女性で，下肢の著明な腫脹の精査目的で入院となった．末梢血管エコー図検査では，右下肢静脈の完全閉塞が認められた．肺梗塞予防のために下大静脈フィルターの留置を左鼠径部より試みたが，静脈造影では腎静脈直上に血栓の付着が認められた．血栓はこん棒状の巨大なもので，腎静脈直上より右房を経て右室に達していた．さらに，その先端は心拍に伴い右房から右室の間を振り子のように出入りを繰り返していた．このため，外科的な血栓摘出術が行われた．摘出された血栓は径15mm，長さ200mmの巨大なもので，病理学的には血球とフィブリンから構成された新鮮な血栓であった．摘出術4日後の，エコー図検査で腎静脈近位部に30mmの血栓の再発が認められた．下大静脈フィルターの留置を試みたが，静脈造影では腎静脈直上に血栓が認められた．このため，2個の下大静脈フィルターを肝静脈下および腎静脈下に留置した．ワルファリンによる抗凝固療法を行い退院したが，血栓症の再発は認められていない．

A 50-year-old woman was admitted to our hospital with marked swelling of the left leg. A venous Doppler study revealed deep vein thrombosis in the external iliac vein and the popliteal vein. Venography with a contrast medium revealed a large thrombus in the inferior vena cava, with its stalk adherent to the proximal portion of the renal vein and its head swaying like a pendulum between the right atrium and right ventricle. The thrombus was removed in many sections, and was composed of coagulated erythrocytes and fibrin. The biggest thrombus resected was 200mm in length,with a diameter of 15mm. A venous Doppler ultrasound conducted on the fourth day after the thrombectomy again revealed a thrombus in the inferior vena cava at the proximal portion of the renal vein. For this reason, two vena caval filters were implanted in the inferior vena cava, one at the distal portion of the renal vein, and the other at the distal portion of the hepatic vein. The patient was then administered anticoagulant therapy, with initial intravenous heparinization, followed by oral warfarin therapy. Thereafter, no recurrence of deep venous thrombosis was observed.