Background and Purpose--Aneurysmal subarachnoid hemorrhage (aSAH) stands out from other subtypes of stroke because of the high early mortality and the risk of complications. Serum glial fibrillary acidic protein (s-GFAP) concentrations are increased after stroke. The aim of this study was to investigate whether s-GFAP could be used as a marker of brain damage and outcome after aSAH.

Methods--Serum samples were obtained on a regular basis from 116 adults during a 2-week period after aSAH and analyzed using an enzyme-linked immunosorbent assay. The World Federation of Neurological Surgeons scale was used for neurological evaluation. Outcome was assessed after 1 year and categorized according to the Extended Glasgow Outcome Scale.

Results--Increased s-GFAP levels were seen in 81 of the 116 patients. Maximum s-GFAP correlated with World Federation of Neurological Surgeons scale on arrival and on days 10 to 15 (r=0.37, P<0.001 and r=0.47, P<0.001, respectively). Furthermore, maximum s-GFAP levels were increased in the patient group with radiological signs of focal lesions acute or at 1 year, compared with the group without focal lesions (P<0.001 in both comparisons). Patients with secondary events (re-bleeding or ischemia) reached maximum levels later in the series and both maximum and final s-GFAP levels increased compared with the levels in patients without secondary events (P<0.001 in all 3 comparisons). Finally, maximum s-GFAP correlated with outcome (r=-0.48, P<0.001) and s-GFAP was an independent predictor of dichotomized outcome.

Conclusions--s-GFAP provides information about brain injury severity and outcome after aSAH, which can be useful as a complement to clinical data.