Low-dose urokinase infusions to treat fibrinous obstruction of venous access devices in cancer patients

Purpose: This study was undertaken to determine the role of low-dose urokinase infusions in treating fibrinous occlusions of venous access devices (VADs) in cancer patients, Patients and Methods: Forty-two patients with VAD occlusions refractory to routine urokinase instillations were documented by x-ray (cathetergram) to have fibrin sleeves at the catheter tips. They were randomized to receive infusions of either urokinase (40,000 U/h) or urokinase with heparin (320 U/h) through their catheters, After 1, 3, 6, and 12 hours of treatment, the function of the VADs was reassessed, Whenever the obstruction had been relieved, the infusion was stopped and a repeat cathetergram was performed. The status of the unoccluded catheters was followed to determine the longevity of the restored function. Results: Twenty-one catheters were treated with urokinase alone and 21 with the combination of urokinase and heparin. In each group, 16 VADs opened within 12 hours of treatment and five did not, By actuarial analysis, the probability was only 0.28 that a reopened catheter would reocclude within 6 months. Conclusion: Low-dose urokinase infusions can restore function to the majority of catheters occluded by fibrin sleeves. Adding heparin to the urokinase does not enhance the efficacy of the infusions. The restored function often persists until the VADs are removed.