Cerebrospinal fluid tissue factor and thrombin-antithrombin III complex as indicators of tissue injury after subarachnoid hemorrhage.

BACKGROUND AND PURPOSE

No marker that reflects and predicts brain injury due to subarachnoid hemorrhage (SAH) and cerebral vasospasm has been reported. We hypothesized that membrane-bound tissue factor (mTF) and thrombin-antithrombin III complex (TAT) in the cerebrospinal fluid (CSF) of patients with SAH become markers indicating brain injury. To evaluate the hypothesis, we correlated levels of mTF and TAT in the CSF of patients with SAH with clinical severity, the degree of SAH, and outcome.

METHODS

We assayed CSF mTF, TAT and myelin basic protein (MBP) in patients with SAH at intervals that included days 0 to 4 and days 5 to 9 after ictus. Classification of clinical severity of disease on admission was based on Hunt and Hess grade, degree of SAH on CT on Fisher's grading, and outcome 3 months after SAH on the Glasgow Outcome Scale.

RESULTS

In the interval from days 0 to 4, mTF and TAT correlated with Hunt and Hess and Fisher grades, and occurrence of cerebral infarction due to vasospasm. Only mTF correlated significantly in this period with outcome. TAT, mTF, and MBP all correlated significantly with each other. From days 5 to 9, only mTF correlated with cerebral infarction, infarction volume, MBP levels, and outcome.

CONCLUSIONS

Both mTF and TAT reflected brain injury from SAH and predicted vasospasm, though mTF was more sensitive and a better predictor of outcome. Unlike mTF, TAT did not correlate with vasospasm during the interval when it most commonly occurs, which raised doubt about thrombin activation as a cause.