Impact on early outcome after endovascular repair of type B dissection without proximal landing zone using Castor single-branched stent graft-a retrospective cohort study.

Background: The early safety and efficacy of Castor branch stents have been demonstrated. However, the effect of aortic arch morphology on endovascular therapy remains an unresolved issue. This study aims to assess the impact of aortic arch morphology on the early outcomes of endovascular repair using Castor stent graft in patients who have acute type B aortic dissection involving the left subclavian artery (LSA).

Methods: This is a retrospective cohort study. From January 2019 to December 2021, forty-one patients scheduled for thoracic endovascular aortic repair (TEVAR) of TBADs from Beijing Anzhen Hospital were enrolled in this retrospective cohort study and divided into two groups based on the length of the proximal landing zone left common carotid artery-LSA (PLZ LCCA-LSA), specifically the distance between the LCCA and the LSA (group A ≤10 mm and group B >10 mm). The study recorded technical success, mortality and aortic-related post-operative adverse events. Morphological indices were analyzed including the bird-beak configuration. The bird-beak configuration refers to the wedge-shaped gap between the undersurface of the endograft and the lesser curvature of the arch. The relationship between the risk of bird-beak configuration and PLZ was assessed with logistic regression analysis. Meanwhile, the relationship between the risk of aortic-related adverse events and bird-beak configuration was assessed with logistic regression analysis. Follow-up data were analyzed by Kaplan-Meier life table analysis.

Results: The study included 41 patients with a mean age of 63.1±9.2 years, of which 80.5% were male. 18 patients from group A and 23 patients from group B were included in the comparative analysis. There were no significant differences in aortic-related adverse events, bird-beak phenomenon and re-intervention between groups A and B in 30-day outcomes. Six-month outcomes: aortic-related adverse events and the bird-beak phenomenon were observed in 11 (26.8%) and 12 (29.3%) patients, respectively. There was a significant difference in the occurrence of aortic-related adverse events (P=0.036) and bird-beak phenomenon (P=0.002) between groups A and B. In comparison to group B, the aortic-related adverse event rate was significantly higher in group A, with event-free rates of 83.3%, 83.3%, and 72.2% at 1, 3, and 6 months, respectively (P=0.020). Multivariable logistic regression analyses revealed that PLZ LCCA-LSA length [odds ratio (OR) 0.79; 95% CI: 0.64 to 0.97; P=0.026] was significantly associated with the occurrence of the bird-beak configuration, and bird-beak (OR 17.19; 95% CI: 2.24 to 131.81; P=0.006) was a significant risk factor for aortic-related adverse events.

Conclusions: TEVAR with LSA revascularization has good early outcomes. However, it is more susceptible to aortic adverse events when the PLZ LCCA-LSA is less than 10 mm in length. This should be carefully considered, taking into account the risks and benefits.