# Evaluation of Spinal Cord Blood Supply with Hyperspectral Imaging of the Paraspinous Musculature During Staged Endovascular Repair of Thoracoabdominal Aortic Aneurysm: A Sub-Study of the Prospective Multicenter PAPA-ARTiS Trial

## TL;DR

This study explores using hyperspectral imaging to monitor spinal cord blood supply changes during aortic aneurysm repair procedures.

## Contribution

The novel use of hyperspectral imaging for non-invasive spinal cord collateral network monitoring during thoracoabdominal aortic aneurysm repair is demonstrated.

## Key findings

- Hyperspectral imaging detected significant changes in tissue oxygenation after endovascular repair procedures.
- StO2 increased immediately after stentgrafting but decreased later, with thoracic regions showing higher oxygenation than lumbar regions.
- MIS2ACE priming showed better recovery of tissue oxygenation compared to stentgraft priming after definitive repair.

## Abstract

Background/Objectives: Our aim was to assess the feasibility of hyperspectral imaging (HSI) to detect changes in tissue oxygenation (StO2) of the back, as non-invasive spinal cord collateral network (CN) monitoring during staged endovascular repair (ER) of thoracoabdominal aortic aneurysm (TAAA). Methods: Between September 2019 and June 2021, 20 patients were treated for TAAA and underwent HSI. They were randomized 1:1 to minimally invasive staged segmental artery coil embolization (MIS2ACE) (n = 10) and staged stentgraft implantation (n = 10) as priming methods. HSI of paravertebral regions was taken during each procedure and up to 10 days after. The primary endpoint was the identification of StO2 changes after ER of TAAA. Results: TAAA Crawford Type II (n = 17) and Type III (n = 3) were treated. After stentgrafting, StO2 increased immediately (p < 0.001), followed by a decrease after 5 days (p < 0.001) and 10 days (p = 0.028). StO2 was significantly higher in the thoracic compared to the lumbar region. There was no significant difference between MIS2ACE and the first stentgrafting for StO2 (p = 0.491). Following MIS2ACE, definitive ER caused a significant decrease in StO2 after 5 days (p = 0.021), which recovered to baseline after 10 days (p = 0.130). After stentgraft priming, definitive ER caused a significant decrease in StO2 after 24 h (p = 0.008), which did not return to baseline after 5 (p < 0.001) and 10 days (p = 0.019). Conclusions: HSI detected significant changes in StO2 in the thoracic and lumbar paravertebral regions during ER of TAAA. These preliminary data suggest the efficacy of MIS2ACE in priming the CN before ER of TAAA.