右側大動脈弓に発症したDeBakey IIIb型急性大動脈解離の1例

A Case of DeBakey Ⅲb Type Acute Aortic Dissection Associated with the Right-sided Aortic Arch

　発症早期より多臓器虚血を呈したDeBakey　Ⅲb型急性大動脈解離が右側大動脈弓に合併した1例を経験した．右側大動脈弓解離を合併した例は極めて稀であり，その報告も少ない．症例は61歳，男性で，胸背部痛，腹痛および両下肢痛を主訴に当科を受診した．胸腹部X線CTおよび血管造影で右側大動脈弓部遠位部〜右総腸骨動脈までの解離を認め，右側大動脈弓に発症したDeBakey　Ⅲb型急性大動脈解離と診断した．横隔膜レベル以下の偽腔は血栓閉塞しており，腹腔動脈，左腎動脈，下腸間膜動脈は造影されなかった．腹部大動脈分岐部に狭窄，右総腸骨動脈に閉塞を認めた．多臓器虚血を呈し，DICも伴っていたため緊急手術を行った．既に腸管壊死状態であり，結腸全切除と右腋窩動脈—両側大腿動脈バイパス術を行い，下肢血流は改善した．しかし，術後2日目に腎不全で死亡した．発症早期より多臓器虚血を伴う急性大動脈解離では，より迅速かつ的確な診断と治療を必要とする．

We encountered a case of DeBakey Ⅲb type acute aortic dissection in the right-sided aortic arch with multiple organ ischemia immediately after onset. Aortic dissection in the right-sided aortic arch as a complica-tion is extremely rare, and there are few reports of such cases. A 61-year-old man was examined in our depart-ment with chest and back pain, abdominal pain and pain in both legs as his chief complaints. In thoracoab-dominal X-ray CT and angiography, dissection was confirmed from the distal right aortic arch to the right common iliac arteries, and DeBakey Ⅲb type acute aortic dissection associated with the right-sided aortic arch was diagnosed. False lumen below the diaphragm level showed thrombotic obstruction, and the celiac, left renal and inferior mesenteric arteries were not imaged. Stenosis of the abdominal aortic bifurcation and obstruction of the right common iliac artery were found. Because of multiple organ ischemia and disseminated intravascular coagulation, an emergency operation was performed. The intestines were already in a necrotic condition. Palliative total colectomy and axillo-bifemoral bypass grafting were performed. Blood circu-lation to the legs improved, but the patient died of renal failure 2 days postoperatively. More rapid and reliable diagnosis and treatment immediately after onset are required in case of acute aortic dissection associated with multiple organ ischemia.