[21] Fibrin begins to build up on the catheter soon after insertion, sometimes developing into a sheath that may completely encase the catheter. In this case, infusions still may be possible ...

Catheter occlusion was defined as "complete ... occlusion due to clotted blood or fibrin sheath, as found by radiography, venography, or physical examination. [25] Hypersensitivity to alteplase ...