Low-Molecular-Weight Heparin for the Out-of-Hospital Treatment of Venous Thrombosis: Rationale and Clinical Results

LMWH preparations have been proven to be safe and effective in the outpatient management of acute DVT. Although LMWHs are more expensive than unfractionated heparin, the lack of need for laboratory monitoring of LMWHs and their potential for outpatient treatment more than offset the drug-related cost difference and result in a net cost savings in favor of LMWHs. LMWHs have undergone limited investigation for the secondary prevention of venous thromboembolism after an initial inpatient course of unfractionated heparin. To date, LMWHs have been given in prophylactic doses in these trials. In this setting, the LMWHs are associated with a similar risk for bleeding as fixed, intermediate-dose unfractionated heparin in patients with a high risk for bleeding. In patients with no increase in bleeding risk, fixed prophylactic-dose LMWH appears to be associated with both a lower risk for bleeding than warfarin (target INR of 2.0 to 3.0) and an increased risk for recurrence, although these findings need to be confirmed in larger trials.