Biomarkers in Patients With Acute Ischaemic Stroke Undergoing Thrombectomy Compared With Controls: A Pilot Study

Detection of cerebral ischaemia is challenging in patients who are anaesthetised, sedated or have reduced levels of consciousness, as neurological examination is difficult or even impossible to assess. Furthermore, as some patients cannot be transported for radiology, for example during surgery, a reliable blood biomarker for detecting acute cerebral events would be of considerable clinical value. We aimed to compare levels of brain injury biomarkers glial fibrillary acidic protein (GFAP), neurofilament light chain (NfL), and total tau (tau) in patients with acute ischaemic stroke (AIS) undergoing endovascular thrombectomy under general anaesthesia or sedation to controls undergoing non-cerebral surgery under general anaesthesia. These biomarkers were chosen because previous studies have demonstrated their potential as blood biomarkers of acute cerebral injury and ischaemic stroke.

In this prospective, observational pilot study, conducted at the Sahlgrenska University Hospital, Gothenburg, Sweden, between 2021 and 2024, GFAP, NfL, and tau were analysed using the Simoa Neurology 4-plex assay, before thrombectomy or surgery and at 2- and 24 h thereafter.

Blood samples from 21 patients with AIS and 19 controls were analysed. GFAP concentrations in patients with AIS increased significantly from baseline to 24 h (median 301.0 → 1443.0 pg/mL; p = 0.001) and were higher than in controls at all time points (p < 0.01). In the controls there was no significant increase in GFAP from baseline to 24 h (p = 0.449). NfL and tau increased significantly in patients with AIS (p = 0.001 and 0.002) but also in the controls (p = 0.001 and 0.047).

GFAP and NfL concentrations were higher in patients with acute ischaemic stroke than in surgical controls at all sampling time points, whereas tau differed only after 24 h. Unlike NfL and tau, GFAP did not increase significantly in controls, suggesting that it may be less influenced by anaesthesia and surgery. These findings support further evaluation of GFAP as a potential biomarker of acute cerebral injury in perioperative and critical care settings.

A biomarker of ischaemic cerebral injury could be attractive to support treatments to protect brain health during anaesthesia and surgery. In a pilot study, glial fibrillary acidic protein emerged as a potential candidate as it was increased in patients undergoing endovascular thrombectomy for large-vessel ischaemic stroke compared to anaesthetised patients undergoing non-cerebral surgery.

ClinicalTrials.gov identifier: NCT03919370.