From Equipoise to Evidence: Pre-Trial Setup of the European Uncomplicated Type B Aortic Repair Clinical Trial

Background Optimal management of uncomplicated type B aortic dissection (uTBAD) remains debated. While thoracic endovascular aortic repair (TEVAR) promotes false lumen thrombosis (FLT) and remodeling, the early clinical profile and long-term benefits in routine practice need further investigation. The pre-trial setup of the European Uncomplicated Type B Aortic Repair (EU-TBAR) program prospectively collated multicenter outcomes to evaluate real-world clinical outcomes of TEVAR for uTBAD across European centers, and to identify independent predictors of mortality, reintervention, and aortic remodeling to inform the design of a definitive randomized EU-TBAR trial. Methods Multicenter observational cohort of consecutive patients undergoing TEVAR for uTBAD and related descending thoracic pathology across European centers. Standardized electronic case-report forms captured demographics, presentation, imaging, procedural details, and outcomes. Primary outcomes were in-hospital and follow-up mortality; secondary outcomes included complications, reintervention, and aortic remodeling. Multivariable logistic regression identified predictors of mortality, reintervention, and remodeling. Results We analyzed 263 patients (mean age 61.4 ± 13.4 years; 79.5% male) from six countries. In-hospital mortality was 9.9%, and mortality during follow-up was 14.1% (median follow-up time ≈ 1 year). Postoperative acute kidney injury (AKI) was the strongest independent predictor of death (odds ratio [OR] 9.93, P < 0.0001); additional predictors included AKI at presentation (OR 4.24, P = 0.012), syncope (OR 3.15, P < 0.0001), and ventilation for >48 hr (OR 2.69, P = 0.024). Higher hemoglobin (OR 0.74 per g/dL, P < 0.0001) and estimated glomerular filtration rate (OR 0.79 per 10 units, P < 0.0001) were protective; reintervention was associated with lower mortality (OR 0.26, P = 0.013). Reintervention occurred in 18.3% at a median of 168 days; discharge endoleak (present in 18.3%) tripled reintervention odds (OR 3.08, P = 0.003). Imaging at discharge and follow-up was performed in 70.7% and 63.9%, respectively. At follow-up, FLT was complete in 42.1% and partial in 39.3%. Remodeling was associated with beta-blockers (descending aorta OR 3.58, P = 0.009), prior thoracic surgery (suprarenal OR 5.47; infrarenal OR 8.33; both P = 0.008), and targeted branch stenting (e.g., celiac OR 31.0, P = 0.016). Female sex independently predicted FLT (OR 11.53, P = 0.022). Survival was lower for emergent cases (65% vs 79–78%; P = 0.039) and in patients with postoperative AKI (36% vs. 86%; P < 0.001). Conclusion This pre-trial setup and analysis successfully confirm the feasibility and methodological foundation for the definitive EU-TBAR trial. There is a clinical equipoise across European centers, with significant practice variation justifying a randomized trial comparing pre-emptive TEVAR versus medical management for uTBAD. Key mortality predictors provide objective criteria for patient selection, while the reintervention rate establishes important trial endpoints.