Controlled trial of ancrod in ischemic stroke.

In a randomized, single-blind study, 30 patients with acute ischemic stroke were treated with either low-molecular weight dextran and mannitol alone (group A, mean age, 63.3 +/- 11.8 years, n = 15) or in combination with the viper venom enzyme ancrod (group B, mean age, 67.9 +/- 7.6 years, n = 15). Lowering of plasma fibrinogen levels to 100-130 mg/dL with ancrod resulted in a significant reduction of the apparent blood viscosity, ie, of 37% at a shear rate of 0.03 s-1, compared with only 7% in group A. Fibrin degradation products increased considerably from 3.1 +/- 0.4 to 154.3 +/- 31.6 mg/L on day 3, while plasminogen decreased from 98.2% +/- 2.0% to 79.8% +/- 2.9% in group B. Global coagulation and platelet function tests were not influenced by either treatment. Neurological score improved by 1.1 arbitrary units (AU) in group A and by 2.6 AU in group B. Five patients in group A and two in group B died during the first two weeks. This preliminary study indicated a slightly better outcome in the ancrod treated patients. The beneficial effect may be due to the anticoagulative and fibrinolytic activity of ancrod rather than its effect on blood viscosity.