Question 2; Doppler ultrasonography reveals thrombosis of both distal legs and no mass demonstrated in the abdomen. What is the proper duration of warfarin treatment in this patient?
Ans: At this point, the patient need to be investigated for possible primary causes of DVT i.e. malignancy / inflammatory or autoimmune diseases / acquired hypercoagulable state. Furthermore, pulmonary embolism should be excluded by using CTPA as well (Tachypnea may suggest PE in this case).
According to the recommendation of ASH2020; guidelines for managements of VTE, any DVT cases (both provoked/unprovoked DVT) should be initially prescribed with a short course of anticoagulant. Thus, this patient should be advised to be initially treated with LMWH for 3-5 days and then continue the treatment with warfarin for 3-6 months as a primary treatment.
After finishing the primary treatment, the patient will be subsequently evaluated by the doctor whether she needs the further indefinite antithrombotic therapy for secondary prevention or not. The decision will be made based on the type of DVT. ( The DVT and/or PE patients with transient risks factors usually do not require antithrombotic therapy after completion of primary treatment. However, for unprovoked DVT/PE cases or those with known chronic risk factors i.e. autoimmune disease, inflammatory bowel disease, the ASH guidelines suggest the use of indefinite antithrombotic therapy in order to prevent recurrent VTE.
Ref: Thomas L. Ortel et al,American Society of Hematology 2020 guidelines for management of venous thromboembolism: treatment of deep vein thrombosis and pulmonary embolism. Blood Adv 2020; 4 (19): 4693–4738. doi: https://doi.org/10.1182/bloodadvances.2020001830