IS Case 185: Fibrin sheath
Imaging Sciences URMC 2008
Publication Date: 2009-05-22
A 51-year-old female with history of breast cancer underwent Mediport placement in the right subclavian vein. While in her oncologist's office, the nurse administering chemotherapy noted difficulty injecting through the port and she was unable to aspirate blood from the port.
Catheter malfunction due to poor flow is a commonly encountered problem. When this occurs soon after placement, the etiology is typically technical, while delayed occurrences are usually due to thrombus formation. Although numerous types of thrombus exist, the most common is the fibrin sheath. All catheters eventually develop a fibrin sheath, but the impact is most significant for apheresis and hemodialysis catheters, which must sustain flow rates greater than 300mL/min through the arterial port. When end or side holes of the catheter are covered by the sheath, the sheath acts like a one way valve – there is difficulty aspirating blood, but the catheter can still be injected with relative ease.
Diagnosis can be confirmed via a flow study, which consists of injecting a small amount of contrast in to the catheter during a fluoroscopic run. Imaging findings include retrograde or proximal flow of contrast around the catheter, within the fibrin sheath.
Treatment options are pharmacologic versus mechanical. Pharmacologic therapy includes urokinase administration (5000U or greater) and TPA (2.5mg in 50mL of saline over 3 hours). Mechanical methods consist of fibrin sheath stripping, balloon occlusion catheter internal disruption and exchange of the catheter over guidewires. Fibrin sheath stripping involves introducing a snare through a femoral vein approach, encircling the snare around the catheter and pulling off the fibrin sheath. Immediate technical success rates for each of these techniques are nearly 100%. A possible complication of fibrin sheath stripping is catheter dislodgement.
- Janne d'Othée B, Tham JC, Sheiman RG. Restoration of patency in failing tunneled hemodialysis catheters: a comparison of catheter exchange, exchange and balloon disruption of the fibrin sheath, and femoral stripping. J Vasc Interv Radiol. 2006 Jun;17(6):1011-5. [PMID: 16778235]
- Waldman DL. Interventional Radiology Secrets. Philadelphia: Hanley and Belfus, 2004.