Indwelling Subclavian Catheters and a Visit with the "Pinched-off Sign"

From the Department of Surgery, Division of Surgical Oncology, University of Calgary. Calgary, Alberta, Canada.

Percutaneously inserted indwelling subclavian vein silastic catheters have revolutionized the administration of chemotherapeutic agents. complications associated with insertion of such lines have always included bleeding, pneumothorax, haemothorax, arterial cannulation, and catheter displacement. Recently a patient receiving 5-fluorouracil and folinic acid for 11 months for small bowel carcinoma experienced a catheter fracture with distal segment embolization in the right atrium. A literature survey revealed 13 cases where mechanical shearing forces on the catheter caused by compression of the catheter between the clavicle and first rib were thought to be the cause for this complication. Interestingly all cases involved patients receiving chemotherapy. Radiologically, potential candidates for catheter fracture can be identified by the pinch-off sign with bending and pinching of the catheter at the thoracic inlet. Recommendations are for more lateral insertions of such percutaneouslhy placed catheters and if the pinched-off sign is seen, then said catheters should be followed radiologically and probably should not remain in situ for longer than 6 months.

Central venous silastic catheters are now frequently used whenever long-term venous access is deemed necessary for total parenteral nutrition or chemotherapy. Use of the percutaneous technique using a split-sheath introducer has been advocated as a rapid and highly effective method for inseertion of such lines 1,2,3. Whereas embolication of catheter tips during placement of subclavian cathers in a well-recognized risk 4, spontaneous fracture and embolization of implanted silastic catheters has rarely been reported. In this paper, I present a patient who had an indwelling Port-A-Cath® system for 11 months and who developed a catheter fracture at the junction of the first rib and the clavicle along with distal catheter embolization. In addition, a literature review along with a review of mechanisms involved is presented.

Case Presentation In December 1986, a female patient was diagnosed at age 33 years with a small bowel adenocarcinoma. This could not be completely resected although the bulk of the disease was removed, and she was placed on intravenous chemotherapy receiving one course per month. She did well until August of 1988 when a laparotomy was performed for an obstructed kidney requiring a left nephrectomy. In November 1988, she presented with a small and large bowel obstructions; a sigmoid colostomy along with 5 small bowel resections were carried out, and a Port-A-Cath® was also inserted in the right subclavian vein using a percutaneous technique. A chest X-ray obtained post-operatively confirmed proper positioning of the catheter (Fig. 1).

*Fig. 1.* Postero-anterior (left) and lateral (right) chest X-rays are shown demonstrating the kink in the silastic catheter (arrows, left frame and inset).
Post-operatively, she was placed on high-dose folinic acid and 5-fluorouracil (5-FU) given at monthly intervals until October 1989 when an attempt at flushing her Port-A-Cath® created intense pain along the course of the subcutaneous catheter. A chest X-ray done at that time revealed that the catheter had fractured at the junction of the first rib and clavicle and that the distal segment had embolized into the right atrium (Fig. 2).

*Fig. 2.* Postero-anterior (left) and lateral (right) chest X-rays done when the patient experienced pain during flushing demonstrating catheter fracture (arrow, left frame) and embolization of distal fragment (arrow, right frame).
The embolized segment was easily removed percutaneously through the right femoral vein; 2 weeks later a new Port-A-Cath® was inserted in the left subclavian vein and removal of the right venous access was also carried out. Examination of the tip of the catheter disclosed a pattern consistent with a fracture secondary to mechanical shearing forces associated with a compressed fish-mouth appearance at the fracture (Fig. 3).
*Fig. 3.* Proximal portion of fractured catheter showing ragged edges consistent with shearing of silastic material and fracture.

A review of all cases of fractured indwelling subclavian catheters inserted into the subclavian vein using the percutaneous approach is presented in Table 1. Two cases were reported by Aitken and Minton 5, 8 by Rubenstien et al. 6, 1 by Brincker and Saeter 7, 1 by Prager and Hertzberg 8, and 1 by Carr 9. If we include the case presented in this paper, the total is now 14. It should be noted that all 14 cases occurred in patients receiving chemotherapy. Although some of the fractures occurred within weeks of insertion (4 weeks), most occurred later with the present case occurring at 11 month. The mean time of insertion before fracture was 6.5 months with a median of 6 months. Where documented, the catheter took on the shape of a fish-mouth at the fracture site documenting compression between the first rib and clavicle. This was also associated with a kink of the catheter that could be visualized on chest X-ray in cases where such radiographs were available. There was no difference in the incidence of catheter fractures between the left and right subclavian veins (left: 5, right: 4, not documented: 5). Catheter size was only available in 4 cases but fractures occurred even when small catheters were inserted (1.0 mm = 3 French). Although most of the fractured catheters were of the Hickman® type, this probably reflects the standard of practice at the time of the published reports. One Broviac ® catheter, one vascular access port, one Infusa-Port ® , and one Port-A-Cath® have also been reported. In all cases reported, transvenous extraction of the embolized segment was successfully carried out.

Catheter embolization for implanted venous access devices is an uncommon event. If we include the case presented in this paper, there are now 14 well-documented cases (Table 1). Even with such a small number, the major risk factors are now apparent. In previous reports by Atiken and Minton 5 and Prager and Hertzberg 8, microscopic and structural analysis indicated that the fracture probably occurred at the site of a pre-existing kink in the catheter. In our own case, the kink could be seen on X-ray films prior to catheter fracture (Fig. 1, insert). Atiken and Minton 5, Rubenstein et al. 6, and Prager and Hertzberg 8, postulated that movement of the clavicle produced intermittent compression of the catheter as it passed over the first rib resulting in shearing forces that weakened the catheter and resulted in subsequent separation. Despite this very plausible postulate, it is most striking to me that all fractures documented thus far have been in patients receiving chemotherapy. Information regarding signs and symptoms associated with catheter embolization is extrememly limited. Patients reports by Prager and Hertzberg 8 and Carr 9 experienced chest discomfort which was spontaneous. The patient reported herein had pain on flushing of the Port-A-Cath® along the tunneled catheter. Most patients, however, were asymptomatic. In all cases documented in Table I except for the case presented by Brincker and Saeter 7, the catheters were retrieved percutaneously and this should be the preferred approach in view of recent technological advances. 10, 11, 12

The percutaneous subclavian method has gained wide acceptance because of ease of insertion. Despite this new complication of catheter fracture, this approach is still preferred as the complication appears to occur in less than 1% of all insertions 6. The following precautions may help minimize the problem: 1) the subclavian puncture should be made at the mid-clavicular location rather than more medially; 2) fluoroscopic assessment at the time of insertion and a chest X-ray in the upright position should be done to look for catheter kinking; 3) in kinking is identified then a chest X-ray at 2 monthly intervals should be done to identify progressions of kinking; 4) if any evidence of kinking is seen on follow-up chest X-ray, the catheter should probably be removed before 6 months has elapsed, as the mean time to fracture in this reivew was 6.5 months, and then replaced if necessary with another catheter.

Medial insertion of silastic subclavian catheters using the percutaneous technique can lead to compression and fracture of such catheters. Chest X-rays to identify catheter compression should be carried out; if such compression is seen, then catheters should be changed before 6 months has elapsed as they are liable to fracture and undergo distal venous embolization. Embolized fragments should be removed percutaneously.

Acknowledgments: The author wishes to thank Ms. Rejeanne Barolet for her excellent secretarial assistance. This research was made possible through a grant from a Alberta Heritage Foundation for Medical Research.