Factors Related to Late False Lumen Enlargement after Thoracic Stent-Graft Placement for Type B Aortic Dissection.

PURPOSE: To evaluate significant factors related to delayed aortic false lumen (FL) enlargement in patients who have undergone thoracic stent-graft placement for type B aortic dissection.

MATERIALS AND METHODS: The study included 62 patients (45 male, 17 female) aged 26-80 years (mean age, 58.1 y) who underwent thoracic endovascular aortic repair for type B aortic dissection at a single institution between January 2005 and May 2015. Mean age of aortic dissections was 5.3 months (range, 0.1-73.3 mo). Maximum aortic diameter at presentation was 41.7 mm ± 8.3. The follow-up period ranged from 3 to 104 months (mean, 27.1 mo). Computed tomographic (CT) angiography studies were reviewed to identify FL diameter enlargements > 5 mm at different levels along and distal to the stent graft. Imaging findings and clinical variables were investigated to determine their correlation with FL enlargement.

RESULTS: No significant difference was found between the ages of aortic dissections in patients with and without FL enlargement (P = .26). On follow-up CT angiography, 16 patients had 2 or more communication channels between the FL and the systemic circulation, 7 of whom showed FL enlargement > 5 mm (P = .007). Twenty-seven patients showed complete FL thrombosis, none of whom had FL enlargement (P < .001).

CONCLUSIONS: Two or more communication channels between the FL and the systemic circulation represent a risk factor for FL enlargement regardless of the age of the dissection. Patients with thrombosis of the FL are less likely to experience FL enlargement.