[Surgical treatment in dissecting aneurysm of the infrarenal abdominal aorta--report of two cases].

In this paper, we present two cases of dissecting aneurysm in the infrarenal abdominal aorta and a review of this type of lesion. DeBakey's classification has found wide acceptance since it combines both anatomical description and a basis for management. However, there is another type of the aneurysm, omitted in this classification, which involves the infrarenal segment of the abdominal aorta, the intimal tear being distal to the renal arteries. Its clinical manifestation, therefore, differs from dissecting aneurysm of the thoracic aorta. The incidence of dissecting aneurysm in the lower abdominal aorta in the literature is 2-14%. Sixteen cases of atraumatic dissecting aneurysm in the abdominal aorta, including our two, have been reported in Japan. Radioimaging techniques such as ultrasound, computerized tomography with contrast enhancement and conventional angiography, allow diagnosis of dissecting aneurysm. Computerized tomography with contrast enhancement has led to more frequent preoperative diagnosis of dissecting aneurysm in the abdominal aorta. However, precise visualization of the intimal defect together with the site of entry is a prerequisite of operation. Angiography remains the most suitable method of achieving this end. Although both abdominal and thoracic aortic dissection share a common management in respect to hypotensive therapy, we believe that surgical intervention is required, especially in dissection of the abdominal aorta, with prosthetic replacement of the infrarenal segment and obliteration of any proximal or distal false lumen.