重症下肢虚血が診断の契機となった高安動脈炎による腹部大動脈縮窄症の1例

Coarctation of the Abdominal Aorta Caused by Takayasu Arteritis Complicated with Critical Limb Ischemia: A case report

要旨　腹部大動脈縮窄症は大動脈縮窄症全体の0.5～2%と稀な疾患である．今回，重症下肢虚血を契機に診断に至った高安動脈炎によると考えられる腹部大動脈縮窄症例を経験したので報告する．症例は41歳，女性．下肢末梢の紫紅色斑および潰瘍の精査，加療目的に入院となった．ABIは右0.43，左0.37と低下していた．大動脈造影にて腎動脈分岐部遠位より両総腸骨動脈分岐部までの腹部大動脈に限局性の狭窄病変を認め，腹部大動脈縮窄症と診断した．治療は，病変部中枢側腹部大動脈より両側外腸骨動脈にY字人工血管を用いてバイパス手術を施行したが約5カ月後グラフト閉塞を来したため，再手術では病変部を切除し人工血管置換術を施行した．手術で得られた切除腹部大動脈縮窄部の病理所見像より成因は高安動脈炎と考えられた．

　A 41-year-old woman was admitted to our hospital for critical limb ischemia. She had suffered from eight months of intermittent claudication and the new occurrence of ischemic ulcer on the bilateral lower extremities. The ankle-brachial pressure index(ABI) on the right was 0.43 and on the left was 0.37, respectively. Preoperative arteriography demonstrated localized coarctation of the abdominal aorta right below the level of the renal arteries, and the patient underwent aorto-bilateral external iliac bypass of these arteries. However, five months after the operation, occlusion of the bypass graft was radiologically diagnosed. Bifurcated graft replacement of the infra-renal aorta to the bilateral common iliac arteries was, therefore, performed. The intermittent claudication subsided, and the bilateral ABI improved after the second operation. From the result of pathological examination of the resected aorta, the etiology of aortic coarctation in the present case was considered to be Takayasu arteritis. Coarctation of the abdominal aorta is a relatively rare disease, the incidence of which is reported between 0.5 and 2 % of all aortic coarctation. Also, the unusual manifestation of aortic coarctation, through critical limb ischemia justifies the report of our case.