[Experimental prevention of deep venous thrombosis with low-molecular-weight heparin using implantable infusion...

We studied the effect of a fractionated heparin, Dalteparine Sodium, on the prevention of thrombosis of veins of the superior vena cava system catheterized by implantable infusion devices. Forty-six patients with solid or lympho-proliferative tumors, whose clinical condition required installation of a such device, were successively included into the study in 1991. The anticoagulant was administered for one month following implantation at the dosage of 2,500 anti-Xa units per day. The development of deep vein thrombosis was investigated by systematic Doppler ultrasound before the first and third months and at 1 year. Three early (D9, D12 and D16) and asymptomatic thrombosis were diagnosed (6.5%). This rate, although clearly more favourable, was not significantly different (p = 0.254) from the rate of 15.2% previously reported in a group of 72 comparable patients, but who did not receive preventive treatment. These results demonstrate the necessity and feasibility of a randomized study on a larger number of patients testing several protocols, before concluding on the efficacy of this type of preventive treatment.