What is the role of anticoagulation in the treatment of calf vein deep venous thrombosis (DVT)?

Updated: Nov 09, 2018
  • Author: Donald Schreiber, MD, CM; Chief Editor: Barry E Brenner, MD, PhD, FACEP  more...
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Answer

Answer

Treatment of isolated calf vein deep venous thrombosis (DVT) is best individualized, taking into account local preferences, patient reliability, the availability of follow-up care, and an assessment of ongoing risk factors. Despite the lower (but not 0) risk of pulmonary embolism (PE) and mortality associated with calf vein DVT, current guidelines recommend short-term anticoagulation for 3 months in symptomatic patients, albeit with a relatively low Grade 2B recommendation. Asymptomatic patients with isolated calf vein DVT do not require anticoagulation, and surveillance ultrasound studies over 10-14 days to detect proximal extension is recommended instead. At certain centers, patients with isolated calf vein DVT are treated with full anticoagulant therapy.

With the introduction of low-molecular-weight heparin (LMWH) or fondaparinux, selected patients qualify for outpatient treatment only if adequate home care and close medical follow-up can be arranged. As discussed, subcutaneous unfractionated heparin (UFH) may be substituted for LMWH or fondaparinux if insurance issues are a limiting factor. Outpatient therapy with UFH carries a higher risk of heparin-induced thrombocytopenia and remains a second-line drug.

While the patient is initiating therapy with warfarin, the prothrombin time (PT) or international normalized ratio (INR) must be monitored closely (daily or alternate days) until the target is achieved, then weekly for several weeks. When the patient is stable, monitor monthly. Inability to monitor INR precludes outpatient treatment of DVT.

Patients with suspected or diagnosed isolated calf vein DVT may be discharged safely on a nonsteroidal anti-inflammatory drug (NSAID) or aspirin, with close follow-up care and repeat diagnostic studies (ie, ultrasonography) in 7 days to evaluate for proximal extension. Patients with suspected DVT but with negative initial noninvasive study results need to be reassessed by their primary care provider within 7 days. Patients with ongoing risk factors need to be reevaluated at 1 week to detect proximal extension because of the limited accuracy of noninvasive tests for calf vein DVT.


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