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Totally implanted venous access systems are widely used in cystic fibrosis and have a low incidence of complications. Whilst local venous thromboses are described with these devices, we have found no previous reports of permanent superior vena caval occlusion.
A woman with cystic fibrosis (CF) had been colonized with Pseudomonas aeruginosa for many years. She required frequent intravenous antibiotic therapy and because of poor peripheral venous access a Port-a-Cath was inserted into the left subclavian vein in March 1994, when she was 19. When not in use, the port was flushed routinely every four weeks by a trained CF nurse using 5 mL heparin solution (1000 U/mL). During use, the device was flushed before and after each access with 5 mL heparinized saline (10 U/mL). In hospital this was done only by designated CF nurses; at home it was done by the patient, after full training.
In September 1995 the patient reported swelling of her arms and face and dilation of the veins on her chest. Superior vena-caval obstruction was diagnosed. Her coagulation profile was normal and blood cultures were negative. Angiography revealed thrombus in the superior vena cava (SVC). Streptokinase (25 000 U) was administered via the Port-a-Cath, and she was anticoagulated with heparin and then warfarin to maintain an international normalized ratio of 2-3 times normal. The symptoms of SVC obstruction resolved and the Port-a-Cath remained patent.
In March 1996 the Port-a-Cath became obstructed once again despite adequate anticoagulation and negative blood cultures, and patency could not be restored with urokinase (25 000 U) instilled into the Port-a-Cath line. The device was therefore removed and a new Port-a-Cath was inserted into the right subclavian vein at the same procedure. Thereafter, anticoagulation with warfarin was maintained. However, in October 1996 the replacement Port-a-Cath became occluded, with symptoms of recurrent SVC obstruction. Magnetic resonance scans revealed that the SVC was blocked in its middle third by organizing thrombus (Figure 1). Despite repeated streptokinase administration into the Port-a-Cath and adequate anticoagulation with warfarin, the catheter remained unuseable and was removed. In 1998 warfarin therapy was stopped and the patient has been maintained on aspirin ever since. The development of collateral venous drainage temporarily improved peripheral venous access. However, over the subsequent four years it has been increasingly difficult to achieve peripheral venous access, and a repeat MRI scan in December 2000 confirmed the persistence of SVC obstruction preventing the use of upper-body central venous cannulation.
Long-term venous access was first described in 1968, when total parenteral nutrition was administered via percutaneous cannulation of the subclavian vein with an externally exiting catheter. By 1973, less thrombogenic silicone rubber catheters were in use. These were further modified by increasing the bore size, and in 1979 Hickman1 developed a novel subcutaneous placement, whereby subcutaneous tunnelling and the associated fibrous adhesions to the Dacron cuff helped reduce infection rates.
Subsequently, central venous access devices have been designed to be totally implanted beneath the skin, with access accomplished by a percutaneous Huber point needle which pierces the silicone septum without coring it out. These totally implanted venous access systems (TIVAS) are favoured by patients because they impose no restrictions on activity or clothing. Once inserted, TIVAS are designed to remain in situ for several years, with a mean survival time exceeding thirty months2. They also have a lower incidence of complications than their external ring counterparts.
Local sepsis has been reported in up to one-third of cases3,4; systemic sepsis is uncommon4 but may require device removal3. Mechanical complications occur in up to half2,4 and include migration, perforation and fragmentation of the septum. In one patient the catheter was severed at the point of entry into the subclavian vein, with migration of the distal 10 cm into the right ventricle5.
Thrombotic events range from obstruction of the system with intraluminal thrombus, reported in 8-40% of cases, to subclavian vein thrombosis in 5%2,3. Thrombolytic agents restore patency in up to two-thirds of these cases2. One CF patient with protein S deficiency developed recurrent deep venous thrombosis when a TIVAS was placed in the left long saphenous vein6. Whilst SVC thrombosis is well described with Hickman catheters, it is rare with TIVAS and only three cases of transient SVC obstruction have been reported. In two of these the obstruction was not confirmed by imaging techniques; all three patients responded well to thrombolytic therapy and anticoagulation.
In our patient, we have demonstrated a new complication of TIVAS insertion—persistent SVC obstruction. This occurred despite adequate care of the port by both patient and CF staff, and persisted despite subsequent full anticoagulation. Whilst the SVC obstruction may have temporarily and paradoxically improved venous access by the development of collateral veins, it is a worrying complication in a CF patient who now once more has very poor peripheral venous access and who at some stage may need heart—lung transplantation. This patient requires frequent courses of intravenous antibiotics to treat her CF chest disease, and venous access has now become extremely difficult. In view of her persistent SVC obstruction, upper-body central vein cannulation is not a viable option. It has been suggested that permanent central venous access may be possible by inserting TIVAS into the inferior epigastric vein7, but we are reluctant to consider this in view of her recurrent thrombotic events and the potential for infection associated with lower abdominal implantation.