Ascending Aortic Diameter
Several papers have investigated geometric changes induced by aortic
dissection, mostly focusing on measurements of aortic diameter. In a
multi-center retrospective study, Rylski et al. characterized the
morphologic changes induced by aortic dissection by comparing
pre-dissection CTAs with post-dissection CTAs in 63 non-Marfans,
non-bicuspid aortic valve patients. They determined that aortic
dissection changes aortic geometry, noting significant increases in
diameter, ellipticity, volume, and tortuosity after aortic dissection.
Interestingly, they determined that post-dissection increases in aortic
diameter were most pronounced in the mid-ascending aorta, where average
maximum diameter was 32% larger after aortic
dissection9. In his study on ascending aortic length,
Wu et al. found 10 patients with pre-dissection CT scans and noted an
average aortic diameter increase of 0.8 cm13.
Therefore, it is not surprising that in our study ATAAD patients had
significantly greater ascending aortic diameter compared with controls.
We evaluated diameter at the STJ and PAB and found that the diameter of
the ascending aorta was greater at the PAB. Additionally, we found that
a cutoff of 5.5 cm diameter at either site along the ascending aorta was
highly specific for ATAAD and was not present in any of the controls.
However, only 18% of cases had a maximum ascending aortic diameter
>5.5 cm, which further reinforces the need for more
sensitive screening criteria.