Impact of initial aortic diameter and false-lumen area ratio on Type B aortic dissection prognosis

OBJECTIVES: Medical treatment is the gold standard for uncomplicated acute Type B aortic dissection (ATBAD). Although endovascular treatment could become an alternative therapy, it is unclear which ATBAD patients should undergo endovascular intervention. We aimed to evaluate the outcomes of patients with uncomplicated ATBAD and identify the risk factors for major adverse events. METHODS: We retrospectively reviewed 134 consecutive patients who underwent initial treatment for uncomplicated ATBAD between 2004 and 2015. Follow-up rate was 98.5%, and the median follow-up period was 47 months. We evaluated the incidence of major adverse events (aortic-related death, aortic surgery and dilated aorta >55 mm) and identified the predictors of major adverse events using multivariable analysis. RESULTS: In-hospital mortality rate was 0.7% (1/134). During follow-up, 46 patients had major adverse events. The 1-, 3-, and 5-year rates of freedom from major adverse events were 79.8%, 71.4%, and 63.6%, respectively. The independent risk factors for major adverse events were initial aortic diameter <40mm (hazard ratio 3.735, 95% confidence interval 1.888-7.390; P < 0.001) and false-lumen diameter < truelumen diameter (hazard ratio 3.411, 95% confidence interval 1.491-7.806; P = 0.004). CONCLUSIONS: Initial aortic diameter <40mm and false-lumen diameter < true-lumen diameter are predictors of major adverse events after uncomplicated ATBAD. Patients with these risk factors may benefit from early endovascular intervention. Clinical registration number: UMIN 000025388, https://upload.umin.ac.jp/cgi-open-bin/ctr-e/ctr-view.cgi?recptno=R000029229.