Long-term predictors of descending aorta aneurysmal change in patients with aortic dissection.

OBJECTIVES: We sought to demonstrate the long-term natural course of descending aorta dilation after acute aortic dissection (AD) and identify early predictors for late aneurysmal change.

BACKGROUND: Aneurysmal dilation of the aorta is a critical late complication in AD patients.

METHODS: Contrast-enhanced computed tomography (CT) was performed during the acute phase in 100 AD patients, comprising 51 type 1 who underwent ascending aorta surgery and 49 type 3 AD patients. Clinical observation was conducted for 53 +/- 26 months, and CT was repeated for 31 +/- 27 months.

RESULTS: Aneurysm (diameter > or =60 mm) occurred in 14.4%, 8.2%, 4.1%, and 3.1% of patients at the upper descending thoracic aorta (UT), mid descending thoracic aorta (MT), lower descending thoracic aorta (LT) and abdominal aorta (AA), respectively. Of 53 patients in whom CT was repeated for > or =2 years, the rates of aorta diameter enlargement at the UT, MT, LT, and AA levels were 3.43 +/- 3.66 mm/year, 3.21 +/- 2.70 mm/year, 2.62 +/- 2.19 mm/year, and 1.93 +/- 3.13 mm/year, respectively (p < 0.01), and aneurysm developed in 15 (28%). The initial false lumen diameter at the UT, the aorta diameter at the MT, and Marfan syndrome were independent predictors of late aneurysm. A > or =22-mm initial false lumen diameter at the UT predicted late aneurysm with a sensitivity of 100% and a specificity of 76%. The patients with initial UT false lumen diameter > or =22-mm (n = 42) showed higher event rate (aneurysm or death) than others (n = 58) (p < 0.001).

CONCLUSIONS: The UT is the major site of late aneurysmal dilation. A large UT false lumen diameter on the initial CT portends late aneurysm and adverse outcome warranting early intervention.