THE TREATMENT OF PROXIMAL VEIN-THROMBOSIS WITH SUBCUTANEOUS LOW-MOLECULAR-WEIGHT HEPARIN COMPARED WITH CONTINUOUS INTRAVENOUS HEPARIN

Low-molecular-weight heparin, compared with unfractionated heparin, ha s a higher bioavailability and a more prolonged half-life. There are l imited data comparing the use of low-molecular-weight heparin with unf ractionated heparin for the treatment of deep vein thrombosis. We have compared fixed-dose, subcutaneous low-molecular-weight heparin given once daily with adjusted-dose intravenous heparin given by continuous infusion in a multicenter double-blind clinical trial for the initial treatment of patients with proximal vein thrombosis. Clinical outcomes were objectively documented. Six of 213 patients receiving low-molecu lar-weight heparin (2.8%) and 15 of 219 patients receiving intravenous heparin (6.9%) developed new episodes of venous thromboembolism (p = 0.07; 95% confidence interval for the difference, 0.02%-8.1%). During initial therapy, major bleeding occurred in one patient receiving low- molecular-weight heparin (0.5%) and in 11 patients receiving intraveno us heparin (5.0%), a risk reduction of 91% (p = 0.006). This apparent protection against major bleeding was lost during long-term therapy. M inor bleeding complications were rare. During the period of the study, 10 patients receiving low-molecular-weight heparin (4.7%) died, as co mpared with 21 patients receiving intravenous heparin (9.6%), a risk r eduction of 51% (p = 0.049). This study shows that low-molecular-weigh t heparin is at least as effective as classic intravenous heparin ther apy and that there was a reduction in deaths and bleeding complication s. Furthermore, low-molecular-weight heparin was more convenient to ad minister. The simplified therapy with low-molecular-weight heparin giv en by once-daily subcutaneous injection without monitoring may allow p atients with uncomplicated proximal deep vein thrombosis to be cared f or as outpatients.