[Venous thromboembolism associated with long-term use of central venous catheters in cancer patients].

Increased incidence of cancers and the development of totally implanted venous access devices that contain their own port to deliver chemotherapy will lead to a greater than before numbers of central venous catheter-related thrombosis (CVCT). Medical consequences include catheter dysfunction and pulmonary embolism. Vessel injury caused by the procedure of CVC insertion is the most important risk factor for development of CVCT. This event could cause the formation of a fresh thrombus, which is reversible in the large majority of patients. In some cases, thrombus formation is not related to catheter insertion. The incidence of CVC-related DVT assessed by venography has been reported to vary from 30 to 60% but catheter-related DVT in adult patients is symptomatic in only 5% of cases. The majority of patients with CVC-related DVT is asymptomatic or has nonspecific symptoms: arm or neck swelling or pain, distal paresthesias, headache, congestion of subcutaneous collateral veins. In the case of clinical suspicion of CVC-related deep venous thrombosis (DVT), compressive ultrasonography (US), especially with doppler and color imaging, currently is first used to confirm the diagnosis. Consequently, contrast venography is reserved for clinical trials and difficult diagnostic situations. There is no consensus on the optimal management of patients with CVC-related DVT. Treatment of CVC-related VTE requires a five- to seven-day course of adjusted-dose unfractionated heparin or low molecular weight heparin (LMWH) followed by oral anticoagulants. Long-term LMWH that has been shown to be more effective than oral anticoagulant in cancer patients with lower limb DVT, could be used in these patients. The efficacy and safety of pharmacologic prophylaxis for CVC related thrombosis is not established and the last recommendations suggest that clinicians not routinely use prophylaxis to try to prevent thrombosis related to long-term indwelling CVCs in cancer patients. Additional studies performed in high risk populations with appropriate dosage and timing will help to define which patients could benefit from prophylaxis.