What is the role of heparin in the initial anticoagulation therapy for deep venous thrombosis (DVT)?

Updated: Oct 30, 2020
  • Author: Donald Schreiber, MD, CM; Chief Editor: Barry E Brenner, MD, PhD, FACEP  more...
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Initial anticoagulation therapy to treat DVT traditionally involves continuous intravenous (IV) heparin until adequate systemic anticoagulation is achieved. Rapid anticoagulation is essential within the first 24 hours of diagnosis, reducing the incidence of recurrent venous thrombosis during the first 3 months from 25% to 5%. [6, 7]

Continuous IV heparin for therapy initiation has been increasingly replaced by single or twice-daily subcutaneous (SC) injections of LMWH. LMWH antithrombotic effects correlate with body weight and permit fixed dosing without laboratory monitoring; LMWH also allows for outpatient treatment of uncomplicated DVT. [8, 9, 10] However, IV heparin remains the treatment of choice for those with end-stage renal failure.

Guidelines recommend short-term anticoagulation with LMWH SC, unfractionated heparin (UFH) IV, fixed-dose UFH SC, or fondaparinux SC. [11] Initial treatment with LMWH, UFH, or fondaparinux should continue for at least 5 days and until the international normalized ratio (INR) is 2 or higher for at least 24 hours. A vitamin K antagonist (VKA) such as warfarin should be initiated together with LMWH, UFH, or fondaparinux on the first treatment day. [11]

Patients with recurrent VTE while on treatment with a non-LMWH anticoagulant should be switched to LMWH therapy. [3] Those who suffer recurrent VTE while on LMWH therapy should receive an increased dose of LMWH. [3]

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