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

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.

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.

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).

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.