Endothelial cell activation after subarachnoid hemorrhage

OBJECTIVE: Evidence from animal experiments suggests that endothelial cell activation plays a pathogenetic role in the development of cerebral ischemia after subarachnoid hemorrhage (SAH). We measured plasma concentrations of two markers of endothelial cell activation, i.e., ED1-fibronectin (ED1-fn) and von Willebrand factor (vWf), among patients with aneurysmal SAH. We analyzed the relationships of concentrations to initial clinical conditions, treatment modalities, and the occurrence of delayed cerebral ischemia. METHODS: We collected 123 blood samples from 27 patients with aneurysmal SAH. Aneurysms were treated surgically in 19 cases, were treated endovascularly in 7 cases, and remained untreated in I case. Twelve patients developed symptomatic delayed cerebral ischemia. RESULTS: Initial concentrations of ED1-fn (4.3 +/- 3.7 mug/ml) and vWf (17.8 +/- 8.2 mug/ml) were higher than the reference values (ED1-fn, 1.7 +/- 0.9 mug/ml, P < 0.001; vWf, 11.5 +/- 5.2 μg/ml, P = 0.003). Concentrations were higher among patients in poor clinical condition at admission, compared with patients in good clinical condition (mean difference, ED1-fn, 5.7 μg/ml, P = 0.04; vWf, 10.4 μg/ml, P = 0.02). Levels of both markers increased significantly after surgery (mean increase, ED1-fn, 7.5 μg/ml, P = 0.01; vWf, 13.2 μg/ml, P = 0.05) and after ischemic episodes (mean increase, ED1-fn, 8.3 μg/ml, P = 0.02; vWf, 5.0 μg/ml, P = 0.04). CONCLUSION: Plasma concentrations of markers of endothelial cell activation were increased early after SAH and were significantly associated with the clinical condition at admission. We also observed a significant increase in concentrations after surgery and after ischemic episodes. Whether endothelial cell activation is a causal or indirectly related factor in the pathogenesis of delayed cerebral ischemia after SAH is still uncertain.