[A case of aortic dissection (DeBakey-I) occurring 20 months after aortic valve replacement].

Simple aortic valve replacement was performed in a 59-year-old man whose ascending aorta was moderately dilated (45 mm) because he had no characteristics of Marfan's syndrome or other connective tissue diseases. However, about 20 months later, reoperation needed to be performed for aortic dissection of DeBakey type I. The pathological findings of the aortic wall obtained at the initial operation revealed cystic medial necrosis. The occurrence of aortic dissection after aortic valve replacement is uncommon but not rare, especially in patients with cystic medial necrosis and/or dilated aortic root. Therefore, in these patients, wrapping or replacement of the ascending aorta may be required at the same time of aortic valve replacement.