# Evaluation of perivascular fat density and residual false lumen formation following TEVAR in Stanford type B aortic dissection

## TL;DR

This study shows that the density of fat around blood vessels can predict if a false aortic channel remains after a specific surgery for aortic dissection.

## Contribution

PVAT attenuation metrics HUΔ and HUratio are identified as novel non-invasive predictors of residual false lumen after TEVAR in TBAD patients.

## Key findings

- Patients with residual false lumen had significantly higher HUΔ and lower HUratio compared to those with closed false lumen.
- HUΔ and HUratio were confirmed as independent predictors of residual false lumen formation after TEVAR.
- Optimal cut-off values for HUΔ and HUratio were identified with high sensitivity and specificity for predicting residual false lumen.

## Abstract

This study aims to investigate the role of perivascular adipose tissue (PVAT) attenuation in predicting residual false lumen formation following thoracic endovascular aortic repair (TEVAR) in patients with Stanford Type B aortic dissection (TBAD). The focus is on the association between PVAT attenuation (HUΔand HUratio) and postoperative outcomes, particularly the development of residual false lumen.

A retrospective analysis was conducted on 132 patients who underwent TEVAR for TBAD at Fujian Provincial Hospital between 2016 and 2024. Patients were classified into two groups based on postoperative imaging findings: those with residual false lumen and those with completely closed false lumen. Data collected included demographic, biochemical, and imaging parameters. PVAT was assessed using computed tomography angiography (CTA), with the TotalSegmenter deep learning model used for automatic segmentation. Two indicators-Hounsfield unit difference (HUΔ) and Hounsfield unit ratio (HUratio)-were calculated.

Patients with residual false lumen showed significantly higher HUΔ (8.75 ± 3.29 vs. 5.16 ± 2.84, P < 0.001) and lower HUratio (0.73 ± 0.13 vs. 0.85 ± 0.11, P < 0.001) compared to those with closed false lumen. Multivariate logistic regression identified HUΔand HUratio as independent predictors of residual false lumen formation after TEVAR. ROC curve analysis revealed optimal cut-off values for predicting residual false lumen: HUΔ > 7.170 (sensitivity 0.895, specificity 0.762) and HUratio ≤ 0.790 (sensitivity 0.947, specificity 0.667).

PVAT attenuation, reflected by HUΔ and HUratio, serves as a significant, non-invasive imaging biomarker for predicting residual false lumen formation after TEVAR in TBAD patients. These findings suggest that preoperative evaluation of PVAT characteristics can help identify high-risk patients and guide postoperative management strategies. Further prospective studies are needed to validate these findings and explore the potential of PVAT modulation in improving long-term outcomes following TEVAR.