A prospective, randomized, blinded, and placebo-controlled trial of intraoperative intra-arterial urokinase infusion during lower extremity revascularization. Regional and systemic effects

This study was designed to evaluate the safety and regional and systemic effects of three doses of urokinase (UK) infused into the distal arterial circulation during routine operative lower extremity revascularization.

One hundred thirty-four patients were prospectively randomized to receive one of three bolus doses of UK (125,000, 250,000, or 500,000 U) or placebo (saline) infused into the distal circulation before lower extremity bypass for chronic limb ischemia. Regional (femoral vein) and systemic (arm) blood was sampled before drug infusion, prereperfusion, and postreperfusion, and systemic blood samples were obtained 2 hours postreperfusion. Assays evaluated plasma levels of fibrinogen, fibrin(ogen) degradation products (FDP), fibrin breakdown products (D-dimer and fragment B-beta 15-42), and plasminogen. Patients were monitored for clinically evident bleeding complications. The Wilcoxon rank-sum test was used to compare different drug doses with the placebo.

Intraoperative bolus UK infusions produced no significant fibrinogen breakdown compared with placebo. There was a dose-related decline in plasminogen levels, which became significant at a dose of 500,000 U of UK (p < 0.001). There were dose-related increases in plasma FDP, which became significant at dose of 250,000 and 500,000 U (p < or = 0.005), and in plasma D-dimer, which were significant at all UK doses (p < 0.001). The changes in plasma fibrinogen and markers of fibrin breakdown were similar in the regional and systemic circulations. There was no increase in operative blood loss, blood replaced, or wound hematoma formation. There was an unexplained increased mortality in the placebo group (21.1% vs. 2.0%, p = 0.033).

Intraoperative bolus UK infusion is safe, with no significant fibrinogen depletion or increased operative blood loss or wound hematoma formation. Dose-related plasminogen activation resulted in significant breakdown in cross-linked fibrin in the distal circulation. Intraoperative bolus UK infusion may be valuable as an adjunct in patients with chronic occlusive disease who are undergoing revascularization. Detailed randomized studies are indicated to establish clinical efficacy.