Clinical approach in deep vein thrombosis

Deep venous thrombosis (DVT) is part of disease called venous thromboembolism (VTE) and is a life threatening condition that can lead to death. The annual incidence is 67 per 100,000 among general population. The primary mechanism is the Virchow triad, which are venous stasis, vessel wall injury, and hypercoagulable state. A balance between thrombogenesis and the body's protective mechanisms (inhibitors of coagulation and the fibrinolytic system) has the important role of venous thrombosis incidence. There are several factors that might contribute to this event, such as genetic factors, and acquired factors (long-haul air travel, cigarette smoking, pregnancy, obesity, oral contraceptive, post-menopausal hormone replacement, surgery, trauma, and others medical conditions like antiphospholipid antibody syndrome, cancer, hypertension, and chronic pulmonary obstructive disease). The clinical evaluation is very challenging since the symptoms and signs are non-specific. Patients usually have a cramp in the lower calf that persists for several days. Physical findings can shows mild palpation discomfort in the lower calf. In massive DVT, patient presents severe thigh swelling and marked tenderness when palpating the inguinal area and common femoral vein. The diagnosis can be established via clinical prediction rules, D-dimer (a degradation product of a cross-linked fibrin blood clot) testing, and imaging examination like compression ultrasonography with Doppler. It has been well established that a clinical prediction rule that takes into account signs, symptoms and risk factors can be applied to categorize patients as having low, moderate or high probability of DVT. The differential diagnoses for DVT are ruptured Baker's cyst, cellulitis, and post-phlebitic syndrome/venous insufficiency. The main goal of DVT management is to prevent the extension of thrombus and pulmonary embolism in the short-term and to prevent recurrent events in the long-term. The standard therapy for DVT is heparin (unfractionated heparin/UFH or low molecular weight heparin/LMWH). The advantage of UFH is that it has a short half-life. Its anticoagulant effect abates after several hours. The disadvantage of UFH is that achieving aPTT target can be difficult and may require repeated blodd sampling and heparin dose adjustment every 4-6 hours. The route of administration and efficacy of LMWH make this the preferred anticoagulant. Based on a meta-analysis comparing the effectiveness of LMWH at a fixed dose with UFH at an adjusted dose, significantly fewer deaths, major hemorrhages and recurrent venous thromboembolisms occurred with the LMWH.