Restrictive bare stent prevents distal stent graft-induced new entry in endovascular repair of type B aortic dissection

Objective: Distal stent graft-induced new entry (SINE) can occur after thoracic endovascular aortic repair (TEVAR) of type B aortic dissection. This study investigated the mechanism of distal SINE and its prevention using a restrictive bare stent (RBS) technique. Methods: From January 2013 to December 2014, 68 consecutive type B aortic dissection patients received endovascular repair at our center. The RBS technique was used with distal oversizing (between the diameter of the thoracic stent graft and the descending aorta true lumen diameter at the level of the intended distal edge of the thoracic stent graft) > 20%. Results: Twenty-three patients received TEVAR with a single thoracic stent graft (TEVAR group, n = 23); the rest received TEVAR combined with the RBS technique (TEVAR thorn RBS group, n = 45). Four distal SINEs occurred in the TEVAR group. Distal oversizing (69.7% 6 35.5% vs 31.2% 6 24.5%; P = .005) and expansion mismatch ratio (132.2% 6 16.9% vs 106.5% 6 11.6%; P <.05) were significantly higher in the SINE patients. Compared with standard TEVAR, TEVAR thorn RBS was associated with significantly lower distal oversizing (TEVAR vs TEVAR thorn RBS group, 59.8% 6 24.7% vs 16.7% 6 7.6%; P <.05), lower expansion mismatch ratio (113.8% 6 14.6% vs 103.8% 6 11.7%; P = .012), and lower distal SINE rate (4/23 [17.4%] vs 0/45 [0%]; P = .011). Compared with the TEVAR group, the false lumen was reduced significantly at the level of the RBS distal edge (P = .029). Conclusions: Excessive distal oversizing and distal expansion mismatch ratio may contribute to the occurrence of distal SINE. The RBS technique reduced the incidence of distal SINE. Based on our midterm and long-term observations, implantation of an RBS may improve aortic remodeling.