Goals of work: To evaluate differences in success rate between two dosages of intraluminal urokinase (IL-UK) for treatment of withdraw occlusion in central venous catheters (CVC) and to confirm the efficacy of a salvage protocol with low-dose systemic urokinase (S-UK) in case of failure of IL-UK or of complete catheter obstruction.
Patients and methods: All malfunctioning or occluded partially implanted indwelling catheters inserted in a 29-month period in children with cancer at two tertiary care centers (Genoa and Turin) in Italy were eligible for this study. In cases of withdraw occlusion, IL-UK was used as first-line treatment with different schedules of administration in the two centers: a 5,000 IU/ml dose was used in Genoa and a 25,000 IU/ml dose in Turin (Protocol A). In case of failure of the front-line protocol or in case of complete CVC occlusion, S-UK at 1,000 IU/kg per hour for 3 h was used as a salvage protocol in both centers (Protocol B).
Main results: There were 81 episodes of malfunction and three of occlusion recorded in 68 CVCs. Protocol A was successful in 75 (92.5%) of the malfunction episodes. In particular, the dose of 5,000 IU of IL-UK was successful in 42 (89%) CVCs while the 25,000 IU dose resolved 33 (97%) of the episodes (not significant). The six patients with CVC refractory to IL-UK and the three subjects with complete CVC occlusion were treated with S-UK. Patency was obtained in seven cases (78%); the remaining two catheters had to be removed.
Conclusions: We found that 5,000 IU of IL-UK were as effective as 25,000 IU to resolve withdrawal occlusion in partially implanted CVCs and that systemic treatment with urokinase may rescue a significant proportion of CVCs refractory to IL-UK or that are apparently completely occluded.