Analysis of Risk Factors for Aortic Enlargement in Patients with Chronic Type B Aortic Dissection

Objectives: Uncomplicated type B aortic dissection is generally treated with medical management including antihypertensive therapy. The purpose of this study is to investigate risk factors associated with the aortic enlargement in medically treated patients. Methods: Between July 2004 and April 2016, 127 consecutive patients with acute type B aortic dissection were treated in our institution. Of these, 104 patients diagnosed with uncomplicated type B dissection were managed medically as an initial treatment. According to the diameter of the dissected aorta, these patients were retrospectively placed into 2 groups: 1) enlargement group (group E: n= 36); and 2) unchanged group (group U: n= 68). Results: There was statistically significant difference regarding the initial diameter of the dissected aorta (group E: 42 +/- 7 mm, group U: 36 +/- 7 mm) (p< 0.01). As regards the aneurysm growth rate, a significant difference between both groups was noted (group E: 10 +/- 32 mm/half-year, group U - 3 +/- 19 mm/half-year) (p< 0.05). In all 104 patients, 42 patients (40.4%) had patent false lumen with the average number of 1.5 intimal tears. Multivariate analysis showed the relationship for aortic enlargement were patent false lumen (p< 0.05, 95% CI 0.407-0.935) and initial aortic diameter (p< 0.01, 95% CI 1.076-1.158). Aortic event free survival (1/5/10 years) was 100/86/77% in group E and 92/79/79% in group U, respectively no differences between two groups (p= 0.747). Conclusions: The medically managed patients with uncomplicated chronic type B dissection showed excellent survival rate during long-term follow-up. The results of surgical or endovascular treatment in patients underwent initial medical therapy were also satisfactory. The patent false lumen and aortic diameter at the onset may impact on aortic enlargement. Considering our results, the feasibility of elective endovascular repairs in stable dissection remains controversial even in the endovascular era. (This is a translation of Jpn J Vasc Surg 2018; 27: 55-60.)