[Mechanical complications at implantation sites].

Mechanical complications of implanted venous access devices are more common than suggested by the literature. Among them, the most severe is catheter embolism, which is due primarily to costoclavicular pinch-off syndrome (POS). POS occurs mainly after infraclavicular approach of the subclavian vein, the incidence being 8/1000 in our experience. Clinical and radiological findings suggestive of rupture should be well known since they require removal of the device. Other access sites (internal jugular vein, cephalic vein, subclavian vein by the supraclavicular approach) seem preferable for long-term catheterization. Loss of adaptation between the site and catheter, precipitated by inopportune attempts at relieving obstruction or by a defective connector, is the second most common cause of embolism. Irrespective of the cause, the embolized fragment must be removed using vascular interventional radiological techniques in order to avoid severe thrombo-embolism. Thrombo-embolism can also result from secondary migration into a vein adjacent of a catheter that was properly positioned initially. This complication can be produced by forceful injections or by intrathoracic pressure changes generated by coughing or intrathoracic disorders. Clinicians should watch carefully for the evidence of central venous line dysfunction that usually accompanies these complications.