Ancrod causes rapid thrombolysis in patients with acute stroke

Clot lysis is desirable in patients with thrombi in arteries and arterioles by a safe rapidly-acting thrombolytic agent. Ancrod cleaves fibrinogen; the resulting circulating ancrod-fibrin stimulates fibrinolysis. Ancrod action and effect were studied in 20 patients with acute developing stroke in a double-blind, placebo-controlled study. Patients were randomly assigned to one of two treatment groups, and received either normal saline or ancrod 0.5 mu/kg in normal saline administered as a constant-rate intravenous infusion over 6 hours. Subsequent doses of ancrod (or saline placebo) were determined daily thereafter for a total treatment period of 7 days. Neither bleeding nor re-thrombosis occurred within the 90 day follow-up period. That ancrod acted rapidly was shown by a significant decrease in functional plasminogen activator inhibitor (PA-I) within 60 minutes, and by significant elevations of fibrin(ogen) degradation products (FDP) and D-dimer within 3 and 4 hours. The biological effect of fibrinolysis in ancrod infused patients was demonstrated by a greater improvement in stroke score when compared to those infused with saline.