Incidence of ultrasound-detected asymptomatic long-term central vein catheter-related thrombosis and fibrin sheath in cancer patients.

BACKGROUND: Most central venous catheter (CVC)-related deep vein thromboses (DVT) are asymptomatic and their incidence and clinical relevance are still under debate. Data on CVC-related fibrin sheaths are scarce. We investigated the incidence of asymptomatic DVT and fibrin sheaths in cancer patients with long-term CVC implantation who underwent Doppler ultrasound surveillance at 1, 6, and 12 months after implantation. Effects of low-weight molecular heparin (LWMH) therapy on DVT and fibrin sheaths were also analyzed.
MATERIAL AND METHODS: This prospective study was performed on a large cohort (n = 400) of patients with cancer aged >18 requiring long-term CVC implantation for chemotherapy infusion. CVC was implanted by a trained qualified staff, according to standardized protocol in a specific surgery. Patients underwent ultrasound examination at 1 and 6 months after CVC implantation to detect 'early' (1 month) and 'late' (6 months) asymptomatic DVT or fibrin sheaths incidence. Sixty-nine patients underwent US examination also 12 months after CVC implantation.
RESULTS: The incidence of CVC-related thrombosis was 0.10 events per 1000 catheter days. Anticoagulation therapy with LWMH resolved 50% of DVT, but no CVC needed removing. Incidence of new onset fibrin sheaths was 0.71 events per 1000 catheter days. Fibrin sheaths resolution occurred independently of LWMH therapy. DISCUSSION: The incidence of asymptomatic DVT in our patients with long-term CVC is very low and does not represent per se an indication for removal of functioning CVC in patients with cancer. Fibrin sheaths are frequent (13%) and never associated with CVC dysfunction.
CONCLUSION: Asymptomatic DVT and fibrin sheaths do not represent per se an indication for removal of functioning CVC in cancer patients who need central vein access.