Diameter changes of the thoracic aorta caused by acute type B aortic dissection.

Background: The impact of type B acute aortic dissection (TBAAD) on historical pre-TBAAD diameters of the thoracic aorta is rarely reported. The aim of this study was to assess the extent of changes in aortic diameters induced by dissection, measured with a computed tomography (CT) scan obtained before and after TBAAD.

Methods: Between January 2004 and December 2014, CT angiography of 50 non-Marfan patients with nonbicuspid aortic valves diagnosed with TBAAD were compared to historical CTs on file.

Results: The ascending aorta and proximal arch showed negligible change. The proximal, mid, and distal aorta diameters changed compared with predissected values (107.7 ± 4.8%, 109.3 ± 4.9%, and 105.7 ± 5.8%, respectively). Neither sex, false lumen status, or mural calcification, nor prior thoracoabdominal aortic ectasia, correlated with the diameter change. Age ≥80 years in the proximal descending aorta did correlate with the diameter change (110.7 ± 4.0% vs 106.1 ± 4.6% p = 0.01).

Conclusions: Although identifying predicting factors for an aortic diameter increase all along with the thoracic aorta was still challenging, the degree of diameter change by aortic dissection was 105.7% to 109.3% in descending thoracic aorta, most prominent in middle descending aorta.