Treatment of acute deep venous thrombosis (DVT) has the following objectives:

• To prevent pulmonary embolism (blood clot in the lung), which can result in death

• To prevent recurrent DVT

• To prevent postphlebitic or post-thrombotic syndrome (edema, pain, increased pigment and hardening of the skin of the lower leg, skin ulceration, and itchiness)

The wearing of compression stockings significantly decreases post-thrombotic syndrome.

Standard treatment for acute DVT is with unfractionated heparin for 5 days by continuous intravenous infusion, with warfarin started on day 1 or 2 and continued for 3 months. Heparin is continued until the INR (international normalized ratio) is within the therapeutic range (2–3) for 2 days. Unfractionated heparin is monitored by means of activated partial thromboplastin time (aPTT) values. aPTT indicates the time it takes for blood clots to form when certain specific conditions exist.