真性腹部大動脈瘤部位より発症した大動脈解離の2例

Two Cases of Aortic Dissection Originating in Abdominal Aortic Aneurysm

　真性腹部大動脈瘤より大動脈解離を発症した稀な2例を経験した．症例1は76歳の男性．主訴は下腹部痛．CTとDSAより紡錘状の腹部大動脈瘤より発症した血栓閉鎖型の大動脈解離（Stanford B型）と診断した．保存的な治療中に破裂し，Y字グラフト置換術を行った．症例2は66歳，女性．主訴は全身倦怠感．腹部に拍動性腫瘤が触知され，当院紹介となった．CTとMRAとDSAを施行し，腹部限局性の動脈解離を伴う真性腹部大動脈瘤と診断しY字グラフト置換術を行った．真性大動脈瘤と動脈解離の合併の報告は比較的少ない．両者の発症機転が異なるためと考えられる．また，Stanford B型の動脈解離は保存的療法でも予後が良いとされるが，真性動脈瘤より発症した場合には破裂の危険が高く，早期の外科的療法が考慮されるべきである．

We reported two cases of aortic dissection originat- ing in abdominal aortic aneurysms (AAA). Case 1. In a 76-year-old man a type B dissection originated in AAA. He was treated conservatively, but he developed an aortic rupture 3 days after the onset. Subsequently, he underwent emergency surgery and recovered. Case 2 A 66-year-old woman was diagnosed as having an abdomial aortic dissection originating in AAA. She was treated surgically, her operative findings agreed with the preoperative diagnosis.

It is generally considered that type B dissection should be treated medically. However, if the aortic dissection originates in or involves AAA, it must be treated surgically to prevent aortic rupture.