Central venous catheters are intravenous devices whose distal end must be located at the atrio cava junction (union of superior vena cava and right atrium). They allow the infusion of irritant drugs, with a pH < 5 or > 9 or hyperosmolar > 600 mosm/l, in patients that sometimes have challenging vascular access.

To use these products safely, it is important to verify that they are well-located in the vein. To make sure the product is well-positioned in the bloodstream, the nurse must verify that saline can be injected easily and if a blood reflux is obtained by aspiration. They are associated with many complications such as extravasation.

Venous catheter dysfunctions can be defined by an inability to aspirate or a difficulty/inability to inject. It can be quantified by a type of Catheter Injection and Aspiration (CINAS) scale (1). This dysfunction prevents the use of the venous line and therefore, requires the cause to be identified.

Several types of complications can lead to central venous catheter dysfunctions. They include mechanical problems, thrombotic problems (phlebitis), occlusion, fibroblastic sheath, etc. The anatomical pathology, physiology and treatments are different.

Mechanical complications

Mechanical causes (catheter migration, kinks, etc.) lead to a displacement of the distal tip, which is no longer at the atrio-caval junction, a position where dysfunctions and thrombosis are more frequent. Their identification requires a chest x-ray.

Other trivial causes that may be hidden under the dressing, such as plicatures, poorly positioned clamps, and blind plugs, must be eliminated.

Thrombosis

Catheter-related thrombosis (2,3) (thrombosis and phlebitis are different things) is a blood clot inside of a vein that occurs in the veins through which the catheter passes.

Catheter-related thrombosis (2,3) is an inflammatory disease of the vein. The different aetiologies are reported below:

It is indeed a disease of the vein.

Diagnosis is ensured using an ultrasound of the vessels or a CT scan with contrast in particular to observe the retro-sternal vessels. Clinical signs may be absent or insidious and characterized with an absence of venous return on the line and may be revealed by signs of very variable intensity: redness, an inflammatory cord, a large painful arm, collateral circulation or even a pulmonary embolism.

Thrombosis can be partial or total, regress with treatment or stabilize by partially or totally occluding the large vessels, leading in its complete form to a superior venous syndrome.

Fibrin sleeve

One of the most frequent causes of central venous catheter dysfunctions is fibrin sleeve (5,6).

Fibrin sleeve is constant and begins as soon as the catheter is inserted. Its exuberant proliferation occurs not infrequently and for reasons that are not well-known. It is initially a proliferation of smooth muscle cells carried away by the needle during puncture. During its evolution with time, these cells are transformed into fibroblastic cells and then, are progressively replaced by collagen. In its ultimate phase, this fibroblast mat can form a flap at the distal end of the catheter and prevent easy blood return.

The patient is always asymptomatic. The diagnosis is based on the opacification of the catheter showing a thickening of the catheter and possibly an exit of the contrast product mimicking a catheter rupture.

In 2022, the diagnosis can also be made by ultrasound when it shows a border > 1 mm around the catheter that leaves the wall of the vein free (6). This is a “catheter wall disease”. Treatment is aimed solely at restoring the patency of the catheter. In the vast majority of cases, patency is restored during pulsed, low-pressure rinsing with physiological saline using 10-ml syringes (7). It is the mechanical action that will release the valve.

When using “Powercathers” (also called high-pressure catheters), a high-pressure pulsed rinsing can be performed. In the hands of experts in interventional radiology and/or with precious large-calibre catheters (dialysis), a stripping of the fibrin sleeve can be proposed. The fibrin sleeve is then released into the pulmonary circulation without any manifestation.

It is important to note that in pure forms, fibrin sleeve is not an indication for fibrinolytics. It is the mechanical action that can destroy the flap. Sometimes, however, an occlusion by a clot can be associated with the fibrin sleeve and be accessible to these agents.

Catheter occlusion

Catheter occlusion is the last aetiology responsible for dysfunctions in central venous catheters. It is an obstruction in the catheter lumen. It may be linked to blood clotting during a reflux), or drug-induced (precipitation during the concomitant use of incompatible drugs, lipidic during parenteral nutrition). In the latter case, injection is progressively difficult. It is therefore a “catheter lumen disease”.

Diagnosis is confirmed when the catheter is completely obstructed and by eliminating other diagnoses (migration, rupture, plicatures). The prognosis involves the catheter clearance and the correct performance of the treatment (chemotherapy, parenteral nutrition, hydration, etc.).

It may require the removal and insertion of another catheter, which is sometimes difficult and entails inconvenience and risks for the patient. Depending on the context, a fibrinolytic lock may be performed. A good methodology for its success is essential. It is compulsory to try to treat a complete drug precipitation even if a lock with a basic or acidic solution is theoretically possible. Treatment with a 70% ethanol lock can also theoretically be proposed for lipid occlusions.

Prevention of these occlusions is essential. It is based on pulsed rinsing, which must be performed by the nurse at each shift, after each medication and each blood reflux (7). Here again, when using “Powercathers” or high-pressure catheters, and only with these catheters, high-pressure pulsed rinsing can be attempted to remove the occlusion.

The wrong use of the same terminology for different entities such as catheter thrombosis or catheter occlusion by radiologists, cardiologists, angiologist, or anaesthesiologist often leads to a wrong answer in the necessary treatment. Thus, long, expensive, and sometimes dangerous anticoagulant treatments are prescribed for fibrin sleeve. Desobstructions by fibrinolytics are used for mechanical or phlebitic problems, or fibrin sleeve. These products put a strain on our budgets and, above all, can be inappropriate.

All in all, central venous catheters dysfunctions disrupt patients’ lives and the organization of care and care units. Furthermore, they can affect the life of the venous line and sometimes the patient. They require a diagnostic approach at the time of their occurrence and an adapted treatment.

The functional character of the catheter can now be demonstrated by a cardiac echography with direct visualization of the solution immediately after its injection (8), thus avoiding many complementary examinations and delays in the initiation of treatments.

Bibliography

1- Goossens GA, De Waele Y, Jérôme M, Fieuws S, Janssens C, Stas M, et al. Diagnostic accuracy of the Catheter Injection and Aspiration (CINAS) classification for assessing the function of totally implantable venous access devices. Support Care Cancer. févr 2016;24(2):755‑61.

2- Balsorano P, Virgili G, Villa G, Pittiruti M, Romagnoli S, De Gaudio AR, et al. Peripherally inserted central catheter–related thrombosis rate in modern vascular access era—when insertion technique matters: A systematic review and meta-analysis. J Vasc Access. janv 2020;21(1):45‑54.

3- Verso M, Di Nisio M. Management of venous thromboembolism in cancer patients: Considerations about the clinical practice guideline update of the American society of clinical oncology. Eur J Intern Med. janv 2020;71:4‑7.

4- Raskob GE, van Es N, Verhamme P, Carrier M, Di Nisio M, Garcia D, et al. Edoxaban for the Treatment of Cancer-Associated Venous Thromboembolism. N Engl J Med. 15 févr 2018;378(7):615‑24.

5- Xiang DZ, Verbeken EK, Van Lommel ATL, Stas M, De Wever I. Composition and formation of the sleeve enveloping a central venous catheter. J Vasc Surg. août 1998;28(2):260‑71.

6- Trezza C, Califano C, Iovino V, D’Ambrosio C, Grimaldi G, Pittiruti M. Incidence of fibroblastic sleeve and of catheter-related venous thrombosis in peripherally inserted central catheters: A prospective study on oncological and hematological patients. J Vasc Access. 12 août 2020;112972982094941.

7- O’Grady NP, Alexander M, Burns LA, Dellinger EP, Garland J, Heard SO, et al. Summary of Recommendations: Guidelines for the Prevention of Intravascular Catheter-related Infections. Clin Infect Dis. 1 mai 2011;52(9):1087‑99.

8- Protocole Echotip ; La Greca JVA 2021 doi :10.1177/11297298211044325