Effect of delayed argatroban treatment on intracerebral hemorrhage-induced edema in the rat.

Studies indicate that thrombin plays an important role in intracerebral hemorrhage (ICH) induced edema formation. However, the time window for administration of a thrombin inhibitor to reduce ICH-induced edema is unknown. Nor is it known whether this time window extends beyond the period when a thrombin inhibitor might exacerbate rebleeding. This study examines whether a thrombin inhibitor, argatroban, can reduce edema formation following intracerebral infusion of 100 microl of blood in the rat, the therapeutic time window for argatroban, and whether argatroban promotes rebleeding. Intracerebral injection of argatroban 3 hours after ICH caused a significant reduction in edema measured at 48 hours. The systemic administration of argatroban (0.9 mg/h) starting 6 hours after ICH also significantly reduced edema formation. There was no protection when the onset of argatroban administration was delayed to 24 hours after ICH. Argatroban did not increase collagenase-induced hematoma volume when given into the clot after 3 hours or given systemically at 6 hours. Our data suggest argatroban may be an effective therapy for ICH-induced edema.