腹部大動脈人工血管置換後遠隔期のStanford B型急性大動脈解離

Stanford Type B Acute Aortic Dissection Complicated by Lower Limb Ischemia Late after Abdominal Aortic Graft Replacement

下肢虚血は急性大動脈解離の重篤な合併症である．腹部大動脈人工血管置換術後遠隔期に解離を発症し下肢虚血を合併した症例の報告は少ない．偽腔の圧排により腹部大動脈人工血管中枢側吻合部で真腔血流途絶が発生すると，重症下肢虚血に陥る1）．腹部大動脈人工血管置換術の際に下腸間膜動脈（IMA）を再建するか否かは，内腸骨動脈血流などに基づいて判断されることが多い．

Leg ischemia is a serious complication of acute aortic dissection. Few cases of lower extremity ischemia due to dissection late after abdominal aortic graft replacement have been reported. Critical limb ischemia occurs when true lumen blood flow is obstructed by the false lumen at the proximal anastomosis of the abdominal aortic graft. Usually, the inferior mesenteric artery （IMA） is reimplanted to the aortic graft to avoid intestinal ischemia. We therein report a case of Stanford type B acute aortic dissection, in which previously reimplanted IMA prevented bilateral lower extremity ischemia. A 58-years-old male with a history of abdominal aortic replacement experienced sudden onset of epigastralgia and subsequent pain in the back and the right lower limb and was admitted to the authors’ hospital. Computed tomography （CT） revealed Stanford type B acute aortic dissection, and occlusion of the abdominal aortic graft, and the right common iliac artery. However, the left common iliac artery was perfused through the reconstructed IMA during previous abdominal aortic replacement. The patient underwent thoracic endovascular aortic repair and thrombectomy, and had an uneventful recovery. For residual arterial thrombi in the abdominal aortic graft, oral warfarin potassium was administered for 16 days until the day of discharge. Since then, the thrombus has dissolved and the patient has been doing well without any lower extremity disorders.