Predictive factors for rupture of thoracoabdominal aortic aneurysm.

PURPOSE: To identify the predictive risk factors for rupture of thoracoabdominal aortic aneurysms (TAA).
METHODS: Thirty-one patients with TAA who did not have the indications for surgical repair of the aneurysm were selected. Inclusion criteria were maximum diameter less than 60 mm, refusal of surgical treatment, and high surgical risk. The selected patients participated in a prospective follow-up study for a median period of 47 months and underwent at least two thoracoabdominal computed tomographic scans a year to measure transverse and anteroposterior diameters. Identification of the predictive factors associated with rupture was undertaken with multivariate analysis by means of Cox regression model.
RESULTS: During the study period five patients underwent elective repair, six died of unrelated causes, nine had aneurysms that ruptured (all with diameters greater than 50 mm), and 11 reached the end of the study without rupture or surgical management. Initial anteroposterior diameter and annual growth rate of the anteroposterior diameter were the variables associated with rupture of the TAA according to the multivariate statistical analysis by means of Cox regression model.
CONCLUSION: We recommend elective repair for a fit patient with asymptomatic TAA with an initial anteroposterior diameter of 50 mm only when there is an annual growth rate of at least 10 mm. Patients with similar diameters but with smaller annual growth rates should be treated conservatively and undergo thoracoabdominal computed tomography every 6 months. Patients with an initial anteroposterior diameter of 60 mm and an annual growth rate of 6 mm should undergo surgical treatment. These guidelines for elective repair of TAA are based on the results of a relatively small series and have to be carefully individualized for each patient.