Correlation between intraoperative near-infrared spectroscopy values and neurologic outcomes in patients undergoing total aortic arch replacement using the frozen elephant trunk technique

Objective To correlate intraoperative near-infrared spectroscopy (NIRS) values with neurologic outcomes in patients undergoing total aortic arch replacement using the frozen elephant trunk (FET) technique. Design Retrospective, single-center registry study using a two-way repeated-measures analysis of variance. Setting Between November 2013 and December 2023, 427 patients were treated for acute and chronic aortic pathologies using the FET procedure. Participants A total of 166 patients with complete NIRS data at all predefined time points were included and retrospectively divided into two groups: patients diagnosed by experienced radiologists and clinicians with stroke and without stroke after FET. Measurements Bilateral NIRS values were recorded continuously and at seven critical time points in each patient, and correlations were made between left- and right-sided NIRS values and stroke. Main Results A total of 23 patients (13.9%) were diagnosed with stroke. There was a significantly higher in-hospital mortality in patients with stroke (21.7%) compared with patients without stroke (7.7%, p = 0.037). Left-sided regional cerebral oxygenation did not show significant difference in patients with versus without stroke (p = 0.550). Differences were detected in right-sided regional cerebral oxygenation trends (p < 0.001) and interhemisphere NIRS at specified time points (p = 0.009). The interaction, time × stroke, however, did not show significant results in any analysis (p > 0.05). Conclusion NIRS is a reliable tool to monitor intraoperative frontal lobe cerebral oxygen saturation. However, its use to predict postoperative stroke remains limited. Further refinements are needed to develop the technique into a prediction tool.