Baseline Descending Aortic Diameter Drives Long-Term Failure of Conservative Management in Uncomplicated Type B Aortic Dissection.

Objective Failure of conservative management in patients with initially uncomplicated acute type B aortic dissection (TBAAD) remains clinically relevant. This study evaluated whether commonly cited imaging-based morphologic features are associated with long-term failure of conservative management.Methods This retrospective single-center cohort study included consecutive patients treated for uncomplicated TBAAD between 2000 and 2018 with high-quality baseline computed tomography angiography and ≥1 year of imaging follow-up. Baseline morphologic parameters were assessed with centerline-based analysis and included descending thoracic aortic diameter (DTAD), ascending aortic diameter, true and false lumen dimensions, and primary entry tear (PET) characteristics. Failure of conservative management was defined as the need for surgical or endovascular intervention >3 months after initial presentation. Cox proportional hazards models evaluated associations between morphologic parameters and subsequent intervention.Results Eighty-nine patients (median age 65 years; 65.2% male) were included with a median follow-up of 7.6 years. During follow-up, 33 patients (37.1%) required aortic intervention, mainly due to aneurysmal degeneration or rapid growth. Baseline DTAD was significantly larger in patients requiring intervention (median 41 mm vs. 37 mm; p=0.026). DTAD ≥40 mm was independently associated with intervention (adjusted hazard ratio [HR] 2.15; 95% confidence interval [CI] 1.05-4.42; p=0.037). DTAD analyzed as a continuous variable remained associated with intervention risk (HR 1.09 per mm; 95% CI 1.02-1.16; p=0.011). Other morphologic features were not associated with aortic growth or need for intervention.Conclusion Baseline descending thoracic aortic diameter was the only morphologic imaging feature consistently associated with long-term failure of conservative management in uncomplicated TBAAD.