Object. Although upregulated adhesion molecule expression has been demonstrated in experimental models of subarachnoid hemorrhage (SAH) and in the cerebrospinal fluid of patients with aneurysmal SAH, the clinical significance of these proinflammatory findings remains unclear. The authors hypothesize that 1) serum levels of soluble intercellular adhesion molecule-1 (ICAM-1) are increased in all patients with aneurysmal SAH shortly after the hemorrhagic event, and 2) elevated soluble ICAM-1 values are associated with poor patient outcome, even when controlling for the severity of the initial hemorrhagic insult.
Methods. One hundred one patients were prospectively enrolled and stratified according to their admission Hunt and Hess grade and functional status at discharge (modified Rankin Scale [mRS] score). Soluble ICAM-1 levels were determined every other day for 12 days post-SAH by using the enzyme-linked immunosorbent assay. Early soluble ICAM-1 levels (post-SAH Days 2–4) were increased compared with levels in control patients without SAH (p < 0.05). Patients with aneurysmal SAH who had a poor outcome (mRS Grades 4–6) had significantly higher soluble ICAM-1 levels over the first 2 weeks post-SAH compared with patients who had a good outcome (mRS Grades 0–3, p < 0.01). This association with outcome was predicted by late increases (Day 6, p = 0.07; Days 8–12, p < 0.05) rather than early increases (p = not significant) and was best seen in patients with Hunt and Hess Grades I and II, in whom only those with poor outcomes demonstrated delayed ICAM-1 elevations (p < 0.05).
Conclusions. These data demonstrate a correlation between soluble ICAM-1 levels and functional outcome following aneurysmal SAH that appears to be, at least in part, independent of the initial hemorrhage.