Background and Purpose--After aneurysmal subarachnoid hemorrhage (SAH), elevated D-dimer levels have been associated with poor clinical condition and outcome. We tested prospectively whether D-dimer values affect outcome after SAH independently of severity of bleeding.

Methods--Previous diseases, and clinical as well as radiological variables, were recorded for 136 patients with SAH admitted within 48 hours after bleeding. Plasma D-dimer was measured in the morning after aneurysm occlusion and at discharge 10 to 12 days after SAH. Factors predicting poor outcome according to the Glasgow Outcome Scale at 3 months after SAH and appearance of cerebral infarction were tested with multiple logistic regression.

Results--Patients with poor outcome had higher D-dimer values than did those with favorable outcome: after surgery, a median 1250 (25th and 75th percentiles 675 and 2900) µg/L versus 720 (350 and 1119) µg/L (P=0.001); and at discharge, 1150 (624 and 2875) µg/L versus 360 (330 and 600) µg/L (P<0.001), respectively. In repeated-measures ANOVA, D-dimer decreased more rapidly (P=0.022) in those with favorable outcome. After simultaneous adjustment for several factors affecting outcome, plasma D-dimer after surgery remained a significant predictor for poor outcome (odds ratio, 1.63 per mg/L; 95% CI, 1.03 to 2.60; P=0.038) but neither for delayed ischemia nor, on follow-up computed tomography in survivors, for cerebral infarction.

Conclusions--Elevated plasma D-dimer after admission independently predicts poor outcome, suggesting that prolonged excess thrombin generation may impair outcome. Repeated high plasma D-dimer values can be useful in discovering patients at increased risk for poor outcome.