The Impact of Oversizing in Thoracic Endovascular Aortic Repair on Long-Term Outcomes in Uncomplicated Type B Aortic Dissection: A Single-Center Retrospective Study.

Purpose: The purpose of this study was to assess the impact of oversizing in thoracic endovascular aortic repair (TEVAR) on early and long-term survival and major adverse events in patients with uncomplicated type B aortic dissection (TBAD).

Methods: Between January 2010 and December 2018, 226 patients who were diagnosed with uncomplicated TBAD and received TEVAR were analyzed retrospectively. The patients were divided into ≤5% oversizing (n=153) and >5% oversizing (n=73) groups. Primary end points were all-cause and aortic-related mortalities. Secondary end points were procedure-related complications, including retrograde type A aortic dissection (RTAD), endoleak, distal stent-induced new entry (SINE), and late reintervention. All-cause and aortic-related mortalities were assessed using the Kaplan-Meier survival method, while procedure-related complications were evaluated using a competing risk model with all-cause death as a competing risk.

Results: Mean oversizing was 2.1%±1.5% in the ≤5% oversizing group and 9.6%±4.1% in the >5% oversizing group. Differences in the 30-day mortality and adverse events between the 2 groups were statistically insignificant. The freedom from all-cause mortality was comparable between the ≤5% oversizing group and the >5% oversizing group (≤5%: 93.3% at 5 years, >5%: 92.3% at 5 years, p=0.957). No significant difference was observed between both groups in the freedom from aortic-related mortality (≤5%: 95.0% at 5 years, >5%: 96.7% at 5 years, p=0.928). However, the competing risk analyses revealed that the cumulative incidence of RTAD was statistically significantly greater in the >5% oversizing group than in the ≤5% oversizing group (≤5%: 1(0.7%) at 5 years, >5%: 6(6.9%) at 5 years, p=0.007). All RTADs occurred within a year of TEVAR. The differences in the cumulative incidences of type I endoleak, distal SINE, and late reintervention were not significant between the 2 groups.

Conclusion: The differences in the 5-year all-cause mortality and aortic-related mortality between patients with uncomplicated TBAD who received TEVAR with ≤5% oversizing and those who got TEVAR with >5% oversizing were insignificant. However, oversizing >5% was considerably associated with an increased risk of RTAD within a year of TEVAR, suggesting that oversizing ≤5% may be the appropriate size for TEVAR in patients with uncomplicated TBAD.

Clinical impact: For patients with uncomplicated TBAD, choosing oversizing ≤5% in endovascular treatment is beneficial to reduce the risk of postoperative retrograde type A aortic dissection. This finding provides a basis for stent size selection in endovascular repair. In addition, one year after TEVAR is the main time period for postoperative retrograde type A aortic dissection, and attention should be paid to the management and follow-up of this period.