土田 佳代子¹, 岡田 昌子², 牧野 隆雄², 内山 なおみ¹, 嶺田 志保¹, 玉田 淳², 五十嵐 康己², 福田 洋之², 加藤 法喜², 三神 大世³

Kayoko TSUCHIDA¹, Masako OKADA², Takao MAKINO², Naomi UCHIYAMA¹, Shiho MINETA¹, Atsushi TAMADA², Yasumi IGARASHI², Hiroyuki FUKUDA², Noriyosi KATO², Taisei MIKAMI³

¹市立札幌病院検査部生体検査課, ²市立札幌病院循環器科, ³北海道大学医学部保健学科

¹Department of Clinical Laboratory, Sapporo City General Hospital, ²Department of Cardiovascular Medicine, Sapporo City General Hospital, ³Department of Health Sciences, Hokkaido University School of Medicine

キーワード : patent foramen ovale, impending paradoxical embolism, pulmonary embolism, venous thromboembolism, thrombus

症例は29歳女性．肺塞栓のため入院．肥満とインターネットで個人輸入した経口避妊薬の服用が発症の危険因子であった．初日の心エコー図検査で右室圧負荷所見を認め，翌日の心エコー図検査にて右房から左房に繋がる蛇状の可動性ひも状エコーを認めた．第3病日に低酸素血症が増悪し，施行した経食道心エコー図検査では血栓は消失しており，右房拡大ならびに卵円孔開存，右‐左シャントを認めた．入院時，CTにより上下大静脈内に多量の血栓の存在が疑われたため外科的治療は行わず，抗凝固・血栓溶解療法を行った．肺塞栓による肺高血圧が小さな卵円孔開存を介する右‐左シャントをもたらし，右房内に流入した浮遊血栓が卵円孔に捕捉され，その後，肺動脈に新たな塞栓を来たしたと推測された．肺塞栓に卵円孔開存が合併した場合予後不良とされているが，本症例は幸いにも内科的治療が著効し，無事退院することが出来た． 肺塞栓における刻一刻と変化する血栓や血行動態を経胸壁心エコー図で繰り返し評価することは，より迅速な治療法選択や治療の効果判定に有用であると考えられた．

We report a 29-year-old woman who presented with clinical features of acute pulmonary embolism. She was obese and took oral contraceptives, which she had obtained by personal import over the Internet. Transthoracic echocardiography revealed right ventricular pressure overload on the first day. On the second day, transthoracic echocardiography showed a serpentine thrombus trapped across the patent foramen ovale (PFO) protruding into the right and left atria. After the appearance of sudden hypoxemia on the third day, transesophageal echocardiography demonstrated right atrial enlargement, and a small right-to-left shunt through a PFO without any intracardiac thrombus. Computed tomography suggested massive thrombi in both the superior and inferior venae cavae. We chose anticoagulation and thrombolytic therapy rather than surgical thrombectomy. We thought elevated right-chamber pressure due to pulmonary hypertension favored the establishment of a right-to-left shunt, and that a long thrombus was temporarily trapped across the foramen ovale and finally caused recurrent pulmonary embolism. Although PFO has been reported to be an important predictor of adverse outcome in patients with pulmonary embolism, the patient recovered rapidly and was discharged from the hospital. It was suggested that serial transthoracic echocardiography is useful for assessing the rapidly changeable pathophysiology in patients with acute pulmonary embolism.