Abstract 19240: Operative Indication for Chronic Dissecting Aneurysm in Descending Thoracic and Thoracoabdominal Aorta

Abstract

Background: Because of a lack of information about the rupture size of chronic dissecting descending thoracic and thoracoabdominal aneurysms, we evaluated the natural history of those aneurysms. Patiens and Methods: Data on 422 patients (mean age, 63.3 ± 11.3; 272 male) with chronic dissection in descending thoracic and thoracoabdominal aorta treated at our institution from 2007 to 2014, were analyzed. Patients with connective tissue disorder, impending rupture of aneurysms, infected aneurysms, and an acute dissection without aneurysms were excluded. Chronic dissection was defined as a dissection more than 2 weeks from symptom onset. The aneurysm diameter at the time of the rupture was measured on CT scan in ruptured aneurysms group (n=21), and initial aneurysmal diameter on CT scan in non-ruptured aneurysms group (n=401). The measurements were performed at maximum short axis diameter of the aneurysm on three-dimensional CT. Results: Midian size of all aneurysms was 4.5 cm (range 3.5 to 9.0 cm) and that of in ruptured aneurysms was 5.9 cm (range 4.5-8.0 cm). The location of aneurysms was descending aorta in 303 patients, thoracoabdominal aorta in 119. Aortic surgery was performed in 150 patients (urgent in 20, elective in 130). Hospital mortality rate were 20% (5/20) in patients with ruptured aneurysms and 2.3% (3/130) in patients with non-ruptured aneurysms. Figure shows the incidences of rupture according to the aneurysm size. The incidence of a rupture increases with larger aortic size. At 3.5 to 3.9 cm, 4.0 to 4.4 cm, 4.5 to 4.9 cm, 5.0 to 5.4 cm, 5.5 to 5.9 cm and more than 6.0 cm, the incidence of rupture was 0%, 0%, 1.2%, 10.2%, 14.3% 20.8%, respectively. The aneurysms more than 5.0 cm were ruptured in 15.1% of patients. Conclusions: Because an elective operation is associated with low mortality, operative indication of chronic dissecting aneurysm in descending and thoracic-abdominal aorta should be considered when its size is 5.0 cm or larger in good-risk patients.