What is the optimal duration of treatment for DVT? An update on evidence-based medicine of treatment for DVT.

Venous thromboembolism, including deep venous thrombosis (DVT) and pulmonary embolism, represent a major source of morbidity and mortality today. Incidence of DVT is estimated to be 56 to 160/100,000 population per year. Systemic anticoagulation with low molecular weight heparin or unfractionated heparin with initiation of oral vitamin K antagonist therapy has been shown to be beneficial in preventing pulmonary embolism and reducing extension and recurrence of DVT. The duration of anticoagulation following an episode of DVT is determined by the greatest predictors of recurrence. These include the presence of reversible risk factors, nonreversible risk factors, and no risk factors (idiopathic or unprovoked DVT). Short durations of anticoagulation are only appropriate for calf DVTs in patients with reversible risk factors. Patients with nonreversible risk factors, such as malignancy and certain inherited thrombophilias with a strong family history of venous thromboembolism will require lifelong anticoagulation. Those with proximal DVT due to reversible risk factors require 3 to 6 months of anticoagulation. Patients with idiopathic DVT require reassessment of risk-to-benefit ratio of hemorrhage from oral vitamin K antagonist therapy compared to reducing risk of recurrence and frequently require prolonged oral anticoagulant therapy. Monitoring with d-dimer and serial ultrasounds may offer an individualized approach to therapy.

East AT ，Wakefield TW 《-》

[The optimal duration of anticoagulant treatment following pulmonary embolism].

The optimal course of oral anticoagulant therapy is determined according to the risk of recurrent venous thromboembolism after stopping therapy and the risk of anticoagulant-related bleeding. Clinical risk factors appear to be important in predicting the risk of recurrence whereas the influence of biochemical and morphological tests is uncertain. The risk of recurrent venous thromboembolism is low when the initial episode was provoked by a reversible major risk factor (surgery): 3 months of anticoagulation is sufficient. Conversely, the risk is high when venous thromboembolism was unprovoked or associated with persistent risk factor (cancer): 6 months or more prolonged anticoagulation is necessary. After this first estimation, the duration of anticoagulation may be modulated according to the presence or absence of certain additional risk factors (major thrombophilia, chronic pulmonary hypertension, massive pulmonary embolism): 6 months if pulmonary embolism was provoked and 12 to 24 months if pulmonary embolism was unprovoked. If the risk of anticoagulant-related bleeding is high, the duration of anticoagulation should be shortened (3 months if pulmonary embolism was provoked and 3 to 6 months if it was unprovoked). Lastly, if pulmonary embolism occurred in association with cancer, anticoagulation should be conducted for 6 months or more if the cancer is active or treatment is on going. Despite an increasing knowledge of the risk factors for recurrent venous thromboembolism, a number of issues remain unresolved. Randomised trials comparing different durations of anticoagulation are needed.

Couturaud F 《-》

Venous thromboembolism: risk factors for recurrence.

Zhu T ，Martinez I ，Emmerich J 《-》

Risk of venous thromboembolism recurrence: high negative predictive value of D-dimer performed after oral anticoagulation is stopped.

Palareti G ，Legnani C ，Cosmi B ，Guazzaloca G ，Pancani C ，Coccheri S ... -  《THROMBOSIS AND HAEMOSTASIS》

How should we determine length of anticoagulation after proximal deep vein thrombosis of the lower limbs?

Siragusa S ，Caramazza D ，Malato A 《-》