To address the lack of information about the size of ruptures associated with chronic dissection in the descending and thoracoabdominal aorta, we evaluated the natural history of this pathology.Methods and Results—
We analyzed data from 571 patients (mean age, 69.4±11.6 years) with unrepaired chronic aortic dissection in the descending or thoracoabdominal aorta with a maximal aortic diameter of ≥3.5 cm from 2007 to 2014. This was a cross-sectional study. Data on the timing of computed tomographic scan were as follows: for ruptured cases: at the time of rupture; for nonruptured cases: the initial aortic diameter. Patients with connective tissue disorders were excluded. The primary end point was evidence of aortic rupture on computed tomographic images. The median maximal diameter was 4.3 cm (limits, 3.5–9.0 cm) for all aortas and 5.6 cm (n=31; limits, 3.6–8.0 cm) for ruptured aortas. For aortic diameters of 4.0 to 4.4, 4.5 to 4.9, 5.0 to 5.4, 5.5 to 5.9, and 6.0 to 6.4 cm, the incidence of rupture was 0%, 3.3%, 15.3%, 18.8%, and 28.6%, respectively. The risk factors for rupture were absence of hypertension, chronic heart failure, chronic-phase dissection, and Yale index.Conclusions—
The risk of aortic rupture increased with an aortic diameter of ≥5.0 cm in patients with chronic aortic dissection in the descending or thoracoabdominal aorta. We would recommend 5.0 cm as an acceptable size for elective resection of subacute or chronic aortic dissection in the descending or thoracoabdominal aorta.