Background and purpose: Early predictors of infarct volume may improve therapeutic decisions in patients with acute cerebral ischemia. We investigated whether measurements of serum astroglial protein S100B can predict a malignant course of infarction in acute middle cerebral artery (MCA) occlusion.
Methods: We included 51 patients (24 women, mean age 69.1+/-12.4 years) admitted within 6 hours after stroke symptom onset caused by proximal MCA occlusion, as shown by magnetic resonance angiography (n=39), intra-arterial angiography (n=4), or transcranial duplex sonography (n=8). Blood samples were drawn at hospital admission and 8, 12, 16, 20, and 24 hours after symptom onset. Serum S100B concentrations were determined using a fully automated immunoluminometric assay. A malignant course of infarction was defined as the occurrence of clinical signs of cerebral herniation within the first 7 days of treatment or the clinical decision to perform decompressive hemicraniectomy caused by critical space-occupying swelling as detected by repeated neuroimaging.
Results: Sixteen patients developed malignant infarction (31%). Beginning with the 12-hour value, mean S100B serum concentrations were significantly higher in patients with a malignant course compared with those without (12 hours 1.23+/-1.24 versus 0.29+/-0.45 microg/L; 16 hours 1.80+/-1.65 versus 0.38+/-0.53 microg/L; 20 hours 1.90+/-1.53 versus 0.44+/-0.48 microg/L; and 24 hours 2.41+/-1.59 versus 0.57+/-0.66 microg/L; all P<0.001). A 12-hour S100B value >0.35 microg/L predicted malignant infarction with 0.75 sensitivity and 0.80 specificity. A 24-hour value >1.03 microg/L provided 0.94 sensitivity and 0.83 specificity.
Conclusions: The serum marker S100B can predict a malignant course of infarction in proximal MCA occlusion. This finding may improve the identification and monitoring of patients at particularly high risk for herniation.