Spontaneous aortic dissection in the presence of coexistent or previously repaired atherosclerotic aortic aneurysm.

Acute aortic dissection occurred in 18 patients who had previously diagnosed atherosclerotic aneurysms of the thoracic and/or abdominal aorta. These patients were reviewed to assess the clinical course when these two forms of aortic pathology coexist. Patients were grouped according to status of their atherosclerotic aneurysm (previously repaired vs. untreated) and the segments of the aorta effected by the acute spontaneous dissection. Group 1 patients (n = 5) had previously undergone-abdominal aortic aneurysmectomy (AAA) repair, and the abdominal aortic suture line effectively terminated the dissection process. In Group 2 patients (n = 5), the acute dissection and the atherosclerotic aneurysm involved different segments of the aorta. Group 3 patients (n = 8) experienced spontaneous aortic dissection involving atherosclerotic aneurysms (five infrarenal, three thoracoabdominal), with threatened or actual rupture occurring in six patients, resulting in three deaths. In Group 3 patients, rupture occurred both at the atherosclerotic aneurysm (four patients) and at the site of the aortic intimal tear of the dissection (two patients) after AAA repair. The use of Magnetic Resonance Imaging (MRI) has proven to be highly accurate in delineating the nature and extent of pathology in recently encountered patients with complicated aortic disease. Coexistence of atherosclerotic aneurysm and acute dissection appears to increase the risk of aortic rupture, in both proximal and distal aortic segments.