BACKGROUND: The high-risk patient cohort of uncomplicated type B aortic dissections (uTBADs) needs to be clarified. We compared uTBAD patients treated with best medical treatment (BMT), with and without aortic growth, from the Acute Dissection Stent Grafting or Best Medical Treatment (ADSORB) trial database. Furthermore, we looked for trends in outcome for aortic growth and remodeling after BMT and thoracic endovascular aortic repair (TEVAR) and BMT (TEVAR+BMT).

METHODS: BMT patients with available baseline and a 1-year follow-up arterial computed tomography scan were identified. True lumen and false lumen diameter was assessed at baseline and at follow-up. Patients with false lumen growth (group I) and without false lumen growth (group II) were compared. Predictors of false lumen and total lumen (aortic) growth were identified. Lastly, BMT outcomes were compared with BMT+TEVAR for false lumen thrombosis and change in false lumen and total aortic diameter in four sections: 0 to 10 cm (A), 10 to 20 cm (B), 20 to 30 cm (C), and 30 to 40 cm (D) from the left subclavian artery.

RESULTS: The dissection was significantly longer in group I than in group II (43.2 ± 4.9 cm vs 30.4 ± 8.8 cm; P = .002). The number of vessels originating from the false lumen at baseline was identified as an independent predictor of false lumen growth (odds ratio, 22.1; 95% confidence interval, 1.01-481.5; P = .049). Increasing age was a negative predictor of total aortic diameter growth (odds ratio, 0.902; 95% confidence interval, 0.813-1.00; P = .0502). The proximal sections A and B showed complete thrombosis in 80.6% in the BMT+TEVAR group compared with 9.5% in the BMT group. In these sections, changes from patent to partial or partial to complete thrombosis were observed in 90.3% of the TEVAR+BMT group vs 31.0% in the BMT group. In sections C and D, the change in thrombosis was 74.1% for the TEVAR+BMT group vs 20.6% for the BMT group. The false lumen diameter increase at section C was larger in the BMT group. Total lumen diameter decreased in sections A and B in the TEVAR+BMT group compared with an increase in the BMT group (-4.8 mm vs +2.9 mm, and -1.5 mm vs +3.8 mm, respectively). Sections C and D showed minimal and comparable expansion in both treatment groups.

CONCLUSIONS: The new imaging analysis of the ADSORB trial patients identified the number of vessels originating from the false lumen as an independent predictor of false lumen growth in uTBAD patients. Increasing age was a negative predictor of aortic growth. Our analysis may help to identify which uTBAD patients are at higher risk and should receive TEVAR or be monitored closely during follow-up.