Chronic subdural hematoma (CSH) is characterized by a net increase of volume over time. Major underlying mechanisms appear to be hemorrhagic episodes and a continuous exudation, which may be studied using labeled
proteins to yield an exudation rate in a given patient. We tested the hypothesis that the concentration of
vascular endothelial growth factor (
VEGF) in
hematoma fluid correlates with the rate of exudation. Concentration of
VEGF was determined in 51 consecutive patients with CSH by the sandwich immune
enzyme-linked
immunosorbent assay technique. Mean values were correlated with exudation rates taken from the literature according to the appearance of CSH on computed tomography (CT) images. The CT appearance of each CSH was classified as hypodense, isodense, hyperdense, or mixed density. Mean
VEGF concentration was highest in mixed-density
hematomas (22,403±4173 pg/mL; mean±standard error of the mean; n=27), followed by isodense (9715±1287 pg/mL; n=9) and hypodense (5955±610 pg/mL; n=18)
hematomas. Only 1 patient with hyperdense
hematoma fulfilled the inclusion criteria, and the concentration of
VEGF found in this patient was 24,200 pg/mL. There was a statistically significant correlation between
VEGF concentrations and exudation rates in the four classes of CT appearance (r=0.98). The current report is the first to suggest a pathophysiological link between the
VEGF concentration and the exudation rate underlying the steady increase of
hematoma volume and CT appearance.With this finding, the current report adds another piece of evidence in favor of the pathophysiological role of
VEGF in the development of CSH, including mechanisms contributing to
hematoma growth and CT appearance.