Ascending aortic length associates to acute aortic dissection

Background Acute Stanford type A aortic dissection is a life-threatening condition that is challenging to predict and prevent. The risk for aortic dissection is known to increase with ascending aortic (AA) dilatation, which sets indication for preventive aortic replacement. Anyhow, most of the dissections occur before aortic diameter reaches the diameter indications of preventive surgery. Purpose To investigate whether, alongside with aortic dilatation, AA elongation affects the increased risk for aortic dissection. Methods This retrospective study included patients treated for Stanford type A aortic dissection (n=102), patients with AA dilatation (max. diameter > 40 mm) (n=134) and healthy controls (n=191). AA length and dimensions were measured from aortic computed tomography angiography (CTA) images. The AA length was defined as a distance between the aortic annulus to the origin of the brachiocephalic trunk. Results AA length was significantly increased in patients with aortic dissection when compared to patients with AA dilatation and to healthy controls (106.2 ± 15.1 mm vs. 96.8 ± 11.2 mm vs. 82.5 ± 8.1 mm; p<0.001). After adjusting AA length to patient's height, BSA, sex and maximal diameter, adjusted length of AA was 99.8 mm in the dissection group, 94.4 mm in the AA dilatation group and 86.0 mm in healthy controls. Thus, when comparing adjusted AA length between the groups, dissected aortas were 13.8 mm longer than in healthy controls and 5.4 mm longer than in dilated non-dissected aortas (p<0.001). Dilated non-dissected aortas were 8.4 mm longer than in healthy controls (p<0.001). In the dissection cohort, 25/102 (24.5%) patients had maximal AA diameter <55 mm and 16/102 (12.7%) patients had maximal AA diameter ≥55 mm alongside with AA length > 110 mm (Table). By combining 110 mm AA length and <55 mm diameter, 58% of the dissection patients would have been identified instead of using only AA diameter ≥55 mm as a cut-off criteria, based on which only 33% patients met the indication for elective surgery. Conclusions To conclude, AA length seems to be a strong predictor of risk of type A aortic dissection and thus might be used as an additional tool in identifying patients for preventive surgery.Cut off - limits