Six-week low-molecular-weight heparin versus 12-week warfarin for calf deep vein thrombosis: A randomized,...

Area of Science:

• Cardiology
• Hematology
• Vascular Medicine

Background:

• Current guidelines recommend 3-month anticoagulant therapy for isolated distal deep vein thrombosis (IDDVT).
• Shorter treatment durations are common in clinical practice, necessitating evaluation of alternative regimens.
• Low-molecular-weight heparin (LMWH) and vitamin K antagonists (VKA) are standard anticoagulants.

Purpose of the Study:

• To compare the efficacy and safety of a 6-week LMWH regimen versus a 12-week VKA regimen for IDDVT.
• To assess non-inferiority of intermediate-dose LMWH over 6 weeks compared to standard VKA treatment.
• To evaluate the composite endpoint of recurrent venous thromboembolism (VTE).

Main Methods:

• A multicenter, open-label, randomized trial involving 260 outpatients with symptomatic IDDVT.
• Patients were randomized to receive either LMWH followed by VKA for 12 weeks or LMWH for 6 weeks (intermediate dosage).
• Primary endpoint: composite of recurrent IDDVT, proximal DVT, or pulmonary embolism (PE) over 6 months follow-up. Study stopped prematurely due to slow recruitment.

Main Results:

• The primary efficacy outcome occurred in 10.8% of patients on LMWH versus 3.8% on VKA (risk difference 0.069).
• IDDVT recurrence was significantly higher in the LMWH group (10.0%) compared to the VKA group (3.1%; p=0.024).
• Clinically relevant bleeding rates were similar between groups (1.6% LMWH vs. 0.8% VKA).

Conclusions:

• Twelve-week VKA treatment appears superior to 6-week LMWH in reducing VTE recurrence risk for outpatients with IDDVT.
• The 6-week LMWH regimen showed a trend towards increased VTE recurrence.
• Further research may be needed to optimize anticoagulant duration for IDDVT, considering the study's premature termination.