卵円孔内にまたがる血栓を認めた切迫奇異性塞栓症

Impending Paradoxical Embolization in a Patient with a Thrombus Straddling the Patent Foramen Ovale

奇異性塞栓症は，卵円孔開存（PFO）などの右左シャントを介して右心系の血栓が左心系へ流入することで発症する．無症状のPFOが奇異性塞栓症の原因となることはよく知られているが，塞栓症状が出現する前に診断されることはまれである．われわれは，深部静脈血栓症（DVT）に伴う肺血栓塞栓症（PE）と，右房からPFOを越えて左房に伸びる血栓を診断し，左心系の塞栓を起こす前に手術できた症例を経験したので報告する．

The patent foramen ovale （PFO） is known as a risk of paradoxical embolism in patients with deep venous thromboses. However, PFO is usually found after systemic embolic symptoms become apparent. A 60-year-old male had complained of dyspnea for two weeks. Ultrasound echocardiography showed a thrombus straddling PFO, and venous echography showed blood clots in the right popliteal and soleus veins. Contrast computed tomography revealed multiple pulmonary embolisms and a thrombus in the right atrium expanding to the left atrium through the atrial septum. The straddling thrombus in the atrium and pulmonary thrombi were extirpated under circulatory arrest with deep hypothermia. An inferior vena cava filter was inserted intravenously four days after surgery. The patient was discharged on the 19th postoperative day without any signs of thromboembolism. Prompt surgery is considered important to prevent thromboembolism in the case of impending paradoxical embolism.