Teaching Case

Fibrin sheath around dialysis catheter tip

The patient was admitted because dysfunction of her permanent percutaneous single lumen dialysis catheter. It was her second catheter within one months because the first one was exchanged for similar problems. Injection into the catheter was always possible but aspiration failed permanently. These clinical findings indicated creation of a fibrin sheath around the catheter. Contrast injection into the catheter revealed that the catheter was patent but there remained a small layer of contrast around the catheter´s tip which did not disappear even after the injection has been stopped. This angiographic finding is typical a fibrin sheath (Fig. 1 a, b). After transfemoral venous access, a 5 F catheter was introduced into the superior vena cava and cavography (Fig. 1 c) excluded formation of a larger thrombus mass around the catheter which would represent the differential diagnosis.

A hydrophilic guidewire was inserted through the dialysis catheter and the tip of the wire was guided into the inferior vena cava . A 15 mm nitinol snare together with a 6 F catheter (Gooseneck Snare, Microvena Inc.) was placed into the inferior vena cava (Fig. 2a) and the tip of the guidewire was caught by closing the snare around it. The guide wire was retrieved together with the snare until the tip of the dialysis catheter was reached by the snare (Fig. 2 b). The snare was opened slightly and advanced over the catheter peeling the fibrin sheath off (Fig. 2c) . About 5 cm more cranial the snare was closed again und pulled over the dialysis catheter in a central direction. This maneuver was repeated three times. Then, blood could be aspirated again through the dialysis catheter. Angiography proved that the fibrin sheath was gone (Fig. 2 d) and the intervention was terminated. Fibrin sheath creation is a possible complication in chronic dialysis catheters. As a first treatment, bolus injection of 5000 IU of urokinase (which is available in Europe) in a volume of 3 to 5 cc is recommended. If this treatment fails, continued infusion of urokinase (15000 IU per hour ) over 6 hours is the next step. If the fibrin sheath has not disappeared thereafter, mechanical peeling may be tried. After mechanical treatment, prevention of sheath formation is important which may be done by routine filling of the catheter by 5000 IU of urokinase in 3 to 5 cc after each dialysis session. Some authors, however, do not recommend fibrinolysis in fibrin sheath formation but favor over the wire exchange of the dialysis catheter. However, although under these circumstances, reoccurrence of fibrin sheath formation is not excluded as it happened in the case presented.