# Perioperative Cerebral Protection and Monitoring of Acute Stanford Type A Aortic Dissection: A Retrospective Cohort Study

## TL;DR

This study shows that near-infrared spectroscopy monitoring during aortic dissection surgery can help predict and reduce brain-related complications.

## Contribution

The study introduces procedure-specific thresholds for cerebral desaturation that guide real-time clinical decisions during aortic dissection surgery.

## Key findings

- ΔNIRS correlated with lower temperatures in Total-Arch and Arch-Stent procedures.
- Higher ΔNIRS values were linked to increased risk of major adverse cardiovascular events.
- Procedure-specific ΔNIRS thresholds were identified to predict stroke and MACE risk.

## Abstract

Background: Optimal cerebral protection strategies for acute Stanford type A aortic dissection (aTAAD) surgery remain controversial. This study aimed to evaluate the role of near-infrared spectroscopy (NIRS)-guided monitoring and its association with clinical outcomes. Methods: We retrospectively analyzed 619 patients undergoing aTAAD surgery (Hemi-Arch, Total-Arch, or Arch-Stent procedures). Intraoperative cerebral oxygenation was monitored using NIRS, with the magnitude of desaturation quantified as ΔNIRS. We assessed correlations between ΔNIRS and nasopharyngeal temperature, employed generalized additive models (GAM) to analyze nonlinear relationships with major adverse cardiovascular events (MACE), and used piecewise logistic regression to identify procedure-specific ΔNIRS risk thresholds. Results: ΔNIRS showed a significant positive correlation with lower temperatures in Total-Arch (R = 0.486, p < 0.001) and Arch-Stent (R = 0.216, p < 0.001) groups. GAM analysis revealed a nonlinear, accelerating relationship between higher ΔNIRS and increased log odds of MACE in Hemi-Arch and Total-Arch groups. Procedure-specific ΔNIRS thresholds were identified: 8.5% for Hemi-Arch, 19.6% for Total-Arch, and 20.9% for Arch-Stent. Patients with ΔNIRS above these thresholds had significantly higher rates of stroke and MACE. Conclusions: This study identifies ΔNIRS as a significant, procedure-dependent intraoperative monitoring indicator in aTAAD surgery, and the proposed risk thresholds provide a rationale for real-time NIRS-guided clinical decision-making.