Impact of Oversizing on the Risk of Retrograde Dissection After TEVAR for Acute and Chronic Type B Dissection

To find a suitable rate of thoracic stent-graft oversizing by exploring its association with the occurrence of retrograde type A dissection (RTAD) after thoracic endovascular aortic repair (TEVAR) for type B aortic dissection.

From January 2013 to June 2014, 203 patients (mean age 55 years; 167 men) with type B aortic dissection underwent TEVAR. The mean rate of oversizing at the proximal landing zone was 10% (range 0%-32%). Patients were stratified into 2 groups based on the degree of oversizing: ≤5% (n=105, mean 1.2%±1.5%) and >5% (n=98, mean 18.5%±2.8%). TEVAR-related complications, including RTAD, stent migration, and type I endoleaks, were analyzed.

There were no significant differences in the preoperative proximal landing zone diameters between the groups (31.1 mm for the ≤5% group vs 31.8 mm for the >5% group, p=0.229). The incidence of type I endoleaks over a mean follow-up 15.1±6.4 months was 5.4% [6 (5.7%) in the ≤5% group vs 5 (5.1%) in the >5% group, p=0.847]. The stent migration rate was low in both groups (1% vs 2%, respectively; p=0.521). The occurrence of RTAD [0 in the ≤5% group vs 11 (11.2%) in the >5% group] was significantly associated with the rate of oversizing (p<0.001).

The early and midterm outcomes of this study demonstrate that ≤5% oversizing may be a suitable option for thoracic endografts used to treat type B dissection. The smaller rate of oversizing can lower the incidence of RTAD without increasing stent migration or type I endoleak rates.