An unresolved complication of the use of totally implantable central venous access ports ... is persistent withdrawal occlusion (PWO), i.e. the unimpeded capacity for infusion of fluids accompanied by the inability to withdraw blood. This study demonstrates the mechanism of persistent withdrawal occlusion and describes a method for resolving this complication. ... In summary, in those patients with central venous access ports, who develop withdrawal occlusion, we have found low dose urokinase infusion effective in resolving withdrawal occlusion by dissolving the fibrin sheath that causes it. This treatment was safe even for compromised cancer patients. We experienced no complications related to urokinase infusion, specifically bleeding. Urokinase was effective in dissolving sheaths that had been present for a prolonged period, and the catheters remained functional for prolonged periods after infusion of urokinase.

Abstracted by permission from The American Surgeon.