Fibrin sheet covering subclavian or femoral dialysis catheters

The fibroblastic sleeve, the neglected complication of venous access devices: A narrative review

The presence of a vascular access device (or of any intravascular foreign body) inside the bloodstream is often associated with the formation of a connective tissue sleeve around the catheter (often named-erroneously-"fibrin sleeve"). Such sleeve is usually a physiological phenomenon with little or no clinical relevance, but its pathogenesis is still unclear, so that it is frequently confused with venous thrombosis; also, its relationship with other major catheter-related complications, such as venous thrombosis and bloodstream infection, is uncertain. This narrative review tries to convey in a systematic form the current knowledge about pathogenesis, incidence, clinical manifestations, diagnosis, and management of this phenomenon.

Usefulness of exchanging a tunneled central venous catheter using a subcutaneous fibrous sheath

OBJECTIVES

The reserve of the venous route to the central veins is important for long-term parenteral nutrition (PN). Frequent catheter-related bloodstream infection (CRBSI) induces occlusion of the venous routes. Therefore, a modified exchange procedure using a tunneled central venous catheter (CVC) with a fibrous sheath was developed to preserve the route to the central veins.

METHODS

Seven patients who required long-term PN received the modified exchange procedure and the outcome of exchanged CVC was retrospectively reviewed.

RESULTS

The procedure was performed 10 times in seven patients. The venous routes were either the subclavicular or the internal jugular vein in all patients. The exchange of the catheter was due to CRBSI or occlusion in almost all patients. The mean duration of new catheter use was 296.2 days following the exchange. Four catheters continued to be used, and the remaining ones were removed. The reasons for removal were severe CRBSI and occlusion, each of which occurred in two catheterized patients, while the reason for removing the remaining catheters was because the patients no longer needed the catheters.

CONCLUSION

The modified catheter exchange using fibrous sheath, even in patients with CRBSI, appears to be an effective procedure for reserving the venous route to the central veins in patients who require either long-term PN or other treatments.

Jugular Vein Catheter Placement: Histologic Features and Development of Catheter-related (Fibrin) Sheaths in a Swine Model

PURPOSE

To evaluate the development and histologic features of jugular vein catheter-related (fibrin) sheaths in a swine model.

MATERIALS AND METHODS

The proposal was approved by the University Committee on the Use and Care of Animals. Tunneled silicone 7-F catheters were placed via a jugular vein in eight swine. The animals were separated into four groups of two pigs each according to catheter indwelling times of 7, 14, 30, and 45 days. After the animals were sacrificed, the catheter, access vein, and cranial vena cava were dissected, removed en bloc, and fixed in formalin. Histologic evaluation was performed by using standard light microscopy on hematoxylin-eosin stained specimens; immunohistochemistry was also performed to confirm specific cell populations.

RESULTS

Catheter-related sheaths that covered 33%-100% of the intravascular catheter length were identified in all eight catheter specimens. After 7 days, catheters had a partial or circumferential mixed cellular and noncellular covering consisting of smooth muscle cells, thrombus, and areas with endothelial cell populations. Sheaths from catheters excised at 14 days were characterized by prominent endothelial cell and smooth muscle cell proliferation. Catheters excised at 30 and 45 days showed less prominent cellularity and more prominent collagen content, in a well-developed sheath, than did those excised at 7 and 14 days. With longer catheter indwelling times, an endothelial layer, indistinguishable from the adjacent vein wall, covered the catheter surface.

CONCLUSION

The sheath that develops around central venous catheters in the swine model consists of cellular and noncellular components. A substantial proportion of the sheath is made up of a smooth muscle cell and collagen layer with overlying endothelial cells.

Thrombolysis for restoration of patency to haemodialysis central venous catheters: a systematic review

Urokinase, previously used to restore patency to thrombosed haemodialysis catheters, is now unavailable in North America. We performed systematic reviews of four questions related to the safety and efficacy of alternative agents for catheter thrombolysis, searching Medline and the Cochrane Controlled Clinical Trials Register. In dialysis patients, large case series have documented that urokinase is safe and effective (>70 % efficacy for catheter instillation, and >80 % for systemic lysis). Experience with streptokinase is limited and allergic complications develop with repeated use. Studies of catheter instillation with 1--2 mg of tPA per lumen reported short-term success in 83--98 % of uses. One non-peer-reviewed study described 44--59 % success using systemic tissue plasminogen activator (tPA), 2.5 mg through each of 2 lumens, over 1 h. Meta-analysis of randomized comparisons of urokinase and tPA as full-dose thrombolytic agents suggested that 1 mg tPA was likely equivalent in thrombolytic potency to 36,000 units urokinase. In nondialysis populations, four case series suggested that catheter instillation with 0.5--2 mg tPA was effective and safe in reestablishing patency, and a randomized controlled trial found 2--4 mg tPA more effective than 5,000--10,000 units urokinase. No complications have been reported in any patient treated with systemic or local tPA for catheter thrombolysis. In studies of fistula thrombolysis with 5--50 mg tPA major complications occurred in one episode in 130 patients treated. This review suggests that 1--2 mg/lumen tPA is a suitable dose for catheter instillation and likely to be more effective than 5000 units/lumen urokinase. Systemic lysis with 5--10 mg tPA is likely to be safe and effective in suitably selected patients. Further studies are needed.

Changes in tunneled catheter tip position when a patient is upright

PURPOSE

To determine the relative changes in position of tunneled catheters from supine to upright patient position and factors affecting catheter tip migration.

MATERIALS AND METHODS

One hundred forty-six different tunneled catheters were placed through the subclavian or jugular veins radiologically, and catheter positions were documented with use of cine radiography at the time of placement. Follow-up chest radiographs were obtained with the patient in the upright position within 48 hours after placement. Catheter tip positions were numbered from 1 to 8, with 1 representing the innominate/superior vena cava junction and 8, the lower right atrium. Patient sex and weight, the site of catheter entry, and the size and type of catheter were correlated with the relative change in position on the follow-up chest radiogrpahs.

RESULTS

There was a statistically significant (P < .0001) change in catheter position on the follow-up chest radiographs, with a mean difference of 1.5 catheter positions (usually mid-right atrium initially to low superior vena cava on follow-up). Catheter tip migration was greater for catheters in the subclavian veins, in females, and in obese patients.

CONCLUSIONS

The catheter tip migrates significantly from the initial position at the time of placement as compared to when the patient assumes the upright position. This knowledge is important in achieving the desired final catheter position.

A surgical technique that allows reuse of an existing venotomy site for multiple central venous catheterizations

During long-term use, central venous catheters are damaged or inadvertently displaced, and replacement is required. The authors developed a technique that allows multiple recatheterizations through an existing venotomy site. The technique is very advantageous for patients who need long-term central venous access.

Transvenous removal of fibrin sheaths from tunneled hemodialysis catheters

PURPOSE

Long-term hemodialysis catheters are prone to significant dysfunction due to fibrin accumulation around their tips. The authors assessed the efficacy of transvenous snare removal of fibrin to prolong function of these catheters.

PATIENTS AND METHODS

Twenty-four procedures were performed in 20 patients with tunneled hemodialysis central venous catheters. Technical success was gauged by venography and the ability to infuse and aspirate catheters. Durable efficacy was assessed by improvement in hemodialysis.

RESULTS

Twenty-two of 24 procedures were performed successfully. In two cases residual material remained despite repeated stripping. Mean preprocedure hemodialysis blood-liters processed per hour increased from 15.1 to 19.1 L/h in the first dialysis session after stripping, and blood flow rates of 300 mL/min or greater were restored. By the fifth dialysis session after stripping, the blood-liters processed per hour dropped to 15.9 L/h as catheter flow rates returned to unacceptable levels.

CONCLUSIONS

Percutaneous fibrin removal with a loop snare provides no durable benefit in improving function of failing hemodialysis catheters.