Predictors of Failure of Medical Management in Uncomplicated Type B Aortic Dissection

Background: Optimal medical therapy (OMT) for uncomplicated type B aortic dissection (uTBAD) provides excellent short-term outcomes but is associated with a high incidence of failure. This study identified predictors of aortic intervention and mortality in uTBAD patients undergoing OMT. Methods: A retrospective review of the Emory University School of Medicine aortic database identified 314 uTBAD patients undergoing OMT from 2000 to 2016. Two hundred sixty-three (84%) patients had imaging at presentation analyzed for maximum aortic diameters (ADs), false lumen (FL) status, and visceral vessel perfusion. Cox proportional hazards models were constructed to estimate hazards ratios (HRs) and identify predictors of OMT failure. Results: The mean age of patients was 58 ± 12 years, and 67% were men. FL status was patent in 59.4%, partially thrombosed in 39.8%, and completely thrombosed in 0.8% of patients. Over a median follow-up of 5.6 (interquartile range, 1.4 to 8.5) years, 44.9% of patients failed OMT and underwent intervention (n = 58 open, n = 83 endovascular). The estimated incidence of OMT failure was 46%. Multivariate analysis identified the presence of diabetes, renal failure, DeBakey 3B dissection, and a descending thoracic AD of 4.5 cm or greater (HR, 1.39; 95% confidence interval, 1.24 to 1.56; p < 0.001) to be independent predictors of failure of OMT. FL status or the distribution of visceral vessels arising from the FL did not predict OMT failure. Conclusions: There is a significant incidence of OMT failure in uTBAD patients. A descending thoracic AD of 4.5 cm or greater at the time of diagnosis is an independent predictor of failure of OMT.