Distal Stent Graft-Induced New Entry: An Emerging Complication of Endovascular Treatment in Aortic Dissection

Background Aortic dissection is a major cardiovascular disease associated with a high mortality rate. In complicated type B dissection, with favorable anatomy, endovascular surgical repair (thoracic endovascular aortic repair [TEVAR]) is considered the treatment of choice. Intimomedial injury induced by stent graft, or stent graft-induced new entry (SINE), has a clinically significant incidence. SINE can occur at the proximal or distal level of the stent graft. The aim of this retrospective study was to investigate the incidence, mechanism, and predictive factors of late distal SINE. Methods We reviewed 139 discharged patients after TEVAR for type B or residual aortic dissection after type A surgery, from January 2007 to March 2013. Three intervals of computed tomography imaging were collected, including before and after primary TEVAR and with the first detection of distal SINE. Four accessible measurement methods for precise size selection of the stent graft before and after the procedure were analyzed at the distal end level of the primary stent graft. Results Among the 139 patients, only 108 had complete preoperative and follow-up imaging and were enrolled in the study. The mean age of the patients was 59.7 ± 11.7 years, and 92 patients (85.2%) were men. Seventy had type B aortic dissection, and 38 had residual aortic dissection after type A surgery. The mean follow-up period was 36.1 ± 25.7 months. During follow-up, distal SINE occurred in 30 patients (27.8%), and 18 of them (60%) underwent secondary TEVAR whereas the remaining 12 patients were medically treated. No statistically significant differences in demographic and clinical conditions were seen between patients with or patients without SINE. The incidence of SINE was lower for acute than for chronic dissection (16% versus 50%). At the multivariate analysis, the independent factors associated with SINE development were the oversizing ratio of the area (odds ratio 1.858; 95% confidence interval: 1.109 to 3.064; p = 0.018) and of the mean diameter (odds ratio 1.858; 95% confidence interval: 1.109 to 3.064; p = 0.018). Conclusions Type B aortic dissection can be treated effectively with TEVAR. The incidence of distal SINE is not negligible but is not associated with poor outcomes. The main determinant of SINE seems to be an excessive oversizing, which is particularly evident in the distal end. More accurate sizing can be obtained by evaluating the area of the true lumen.