Central vein stenosis (CVS) is a well-known complication of central venous catheterization, especially after insertion of temporary hemodialysis catheters (tHDC). Incidence and prevalence differ between studies, and exact figures are hard to tell since proper venographies seldom are performed unless the patient is symptomatic.

Most tHDC are placed in the jugular or femoral veins as catheters in the subclavian veins have been shown to result in CVS to a greater degree. However, some studies are equivocal and there are several advantages with the subclavian vein such as a lower risk for infectious and thrombotic complications, longer durability (thereby avoiding placement of a new catheter with repeated tissue trauma), increased comfort during insertion and use, less effect on blood flow if the patient moves the head, easier to mobilize.

The studies on CVS incidence originate from the 1990s when ultrasound-guided insertions were unheard of and polyurethane catheters were prevalent. The investigators believe that there is less tissue trauma when using ultrasound guidance in real-time. Furthermore, CVS is less common when silicone catheters are used instead of polyurethane catheters.

To avoid unnecessary vascular trauma and patient suffering, any pre-existing CVS should ideally be detected before cannulation attempts. A CT scan of the chest with IV contrast is preferred, but this exposes the patient to ionized radiation, is time-consuming and (although debated) may cause contrast-induced nephropathy. A brief ultrasound examination to verify central venous patency would be useful provided it is shown to have an adequate sensitivity for stenosis detection.

This is a multicentric, prospective, randomized, controlled, assessor-blinded, non-inferiority trial. Patients will be enrolled in three hospitals (Lund, Malmö, Helsingborg) in southern Sweden. The trial is investigator-initiated and non-commercial. The radiologist interpreting CT venographies will be blinded to study group allocation, whereas the patient, the treating physicians and other care providers will not be blinded.

Patients will be randomized to receive a silicone tCDC either in the right subclavian vein (intervention) or in the right internal jugular vein (control). All catheterizations will be performed in a standardized manner. A questionnaire regarding the patient's experience of the catheterization procedure is handed out as soon as possible, preferably immediately after catheterization if the clinical situation permits.

Follow-up is carried out 3-6 months after the removal of the catheter to eliminate transitory thrombosis. A CT venography with a customized protocol for this study will be performed to look for CVS. An ultrasound examination of the central veins is performed and compared to the findings of the CT venography.

Inclusion Criteria:

• Adults (18 years of age or older).
• In need of a tCDC with an expected treatment time of at least 7 days.
• Informed consent.

Exclusion Criteria:

• Intravenous pacemaker or a PICC-line via right-sided central veins in situ.
• Known right-sided CVS.
• AV fistula on the right upper extremity.
• History of central venous vascular interventions including stents, dilatations and more (but not previous central venous catheterization).
• Central venous catheter in the right internal jugular vein or in the right subclavian vein in situ.
• Either the right jugular vein or the right subclavian vein unavailable for catheterization due to, e.g., local skin infection, thrombosis or inability to visualize the vein with ultrasound.
• Known allergy to iodinated contrast agents.
• BMI >35 kg/m2.
• No study physician available for the catheterization.