Assessment of Neurone-Specific Enolase, Glial Fibrillary Acidic Protein and S100 B as Spinal Cord Ischemia Biomarkers in Patients Undergoing Open and Endovascular Complex Aortic Surgery: A Single-Center Experience

Abstract

Despite all efforts, spinal cord ischemia (SCI) is a relevant and feared complication after open and endovascular thoracoabdominal aortic aneurysm (TAAA) repair. Besides the established correlation of motor evoked potentials (MEPs) and SCI, the usage of biomarkers for early detection of SCI intraoperatively and postoperatively after TAAA surgery is scarcely described in literature. The methods include retrospective assessment of 33 patients (48.48% male) undergoing open and endovascular TAAA repair between January 2017 and January 2018. Levels of the biomarkers neurone-specific enolase (NSE), glial fibrillary acidic protein (GFAP), and S100B were correlated with a decrease of the amplitude of the MEPs of more than 50%, indicating SCI. Linear mixed models were applied to test for differences in the biomarker levels between open and endovascular surgery and between different times of measurement. Post hoc analyses were performed using Tukey's multiple comparisons test. Logistic regression models were used to investigate the association between GFAP, NSE, and S100B levels at different times and a significant decrease in MEP or in-hospital mortality. Altogether, 19 patients were treated by endovascular repair; 14 patients were treated by open repair; 5 patients were treated because of a type I TAAA; 7 received treatment because of a type II TAAA; 7, 10, and 4 patients received type III, IV, or V TAAA repair, respectively. In-hospital mortality was 18.18% (n=6); 5 of these patients were treated because of symptomatic TAAA. MEP decrease could be observed in 18 cases (54.5%), with 16 (48.4%) recovering during the intervention. SCI could be observed in 9.09% (n=3), 2 endovascular repairs leading to paraplegia and one open repair leading to paraparesis. All biomarkers showed increasing levels over time, with no statistically significant difference between open and endovascular repair. The difference in NSE and S100B levels between the different times of measurements was statistically significant (P<0.0001, P=0.0017, respectively). In a univariable logistic regression analysis, no correlation with the end points "significant decrease in MEP" or "in-hospital mortality" was observed for any of the assessed biomarkers. SCI-related biomarkers, namely NSE and S100B, show a relevant increase directly after open and endovascular TAAA surgery, while no clear association between these biomarker levels and an intraoperatively measurable indicator for SCI could be observed.