# Castor stent reconstruction of left subclavian artery reduces the incidence of postoperative cerebral infarction of type B aortic dissection with insufficient proximal landing area: a propensity score matched analysis

## TL;DR

Using a Castor stent to reconstruct the left subclavian artery in aortic dissection patients may reduce the risk of postoperative brain infarction compared to partial coverage.

## Contribution

This study demonstrates that Castor stent reconstruction reduces postoperative cerebral infarction in TBAD patients with insufficient proximal anchoring.

## Key findings

- The Castor group had significantly lower risk of postoperative cerebral infarction (HR 0.228, P = 0.013).
- Symptomatic stroke risk was significantly lower in the Castor group (HR 0.102, P = 0.008).
- No significant difference was found in silent brain infarcts between the groups.

## Abstract

Compared with conventional treatment of type B aortic dissection (TBAD) with insufficient proximal anchoring by covering the left subclavian artery (LSA), reconstructing LSA with Castor branch stent is a promising strategy. Prior studies lacked comparisons with partial LSA coverage, so we used propensity score matching analysis (PSMA) to retrospectively evaluate both approaches.

We studied 377 patients with thoracic aortic dissection (TBAD) who underwent thoracic endovascular aortic repair (TEVAR) at one center. Of these, 262 had partial LSA coverage, and 115 had LSA reconstruction with a Castor stent. Using PSMA, we created 92 matched pairs for analysis. Kaplan–Meier and Cox regression analyses were conducted to assess the primary outcome of any postoperative cerebral infarction, encompassing both symptomatic strokes and silent brain infarcts, with each component also evaluated as secondary outcomes. Symptomatic strokes were confirmed by neurological symptoms combined with magnetic resonance imaging (MRI) or computed tomography (CT) scans, while silent brain infarcts were detected through routine postoperative CT/MRI scans for all patients, and both outcomes were included in the primary composite outcome of postoperative cerebral infarction. Additionally, all-cause mortality and postoperative LSA occlusion were examined. The Castor group showed less renal insufficiency (18.7% vs. 38.3%, P < 0.01) and was younger (52 vs. 62 years, P < 0.01). Baseline parameters were balanced after PSMAIn the matched cohort, overall median follow-up was 26 months (IQR 16–38); 30 months (IQR 22–38) for the Castor group and 24 months (IQR 14–36) for the partial coverage group, with total follow-up of 433.8 person-years (232.9 vs. 200.9 person-years). No notable differences existed in the unmatched cohort. Post-PSMA, the Castor group had significantly lower risk of postoperative cerebral infarction (HR 0.228, 95% CI 0.063–0.820, P = 0.013) and symptomatic stroke (HR 0.102, 95% CI 0.013–0.817, P = 0.008), with no difference in silent brain infarcts (HR 0.584, 95% CI 0.097–3.508, P = 0.552).

In TBAD with insufficient proximal anchoring, Castor branch stent reconstruction reduces cerebral infarction over a median follow-up of 26 (IQR 16–38) months (433.8 total person-years), compared to partial LSA coverage.