Duration of anticoagulant therapy for VTE

The duration of anticoagulant therapy for venous thromboembolism (VTE) (ie deep vein thrombosis [DVT] or pulmonary embolism [PE]) is influenced by the presence or absence of provoking factors, the patient’s risk factors for recurrence of VTE or bleeding, and patient preference.

Examples of provoking factors include major surgery, hospitalisation with immobilisation, estrogen-containing therapy, and pregnancy and the postpartum period.

Common factors that predict recurrence of VTE are listed in Common factors predicting recurrence of venous thromboembolism.

Assess the risk of bleeding. Factors that predict an increased likelihood of bleeding include a prior bleeding episode, active peptic ulcer disease and oesophageal varices.

Suggested durations of anticoagulant therapy to treat acute VTE are outlined in Suggested duration of anticoagulant therapy to treat acute venous thromboembolism.

Figure 1. Common factors predicting recurrence of venous thromboembolism. Ortel, 2020Tran, 2019

unprovoked VTE:

no major provoking factor in the 3 months before the diagnosis of VTE (eg surgery with general anaesthesia for 30 minutes or more, confined to a hospital bed for 3 days or more with acute illness)
no minor transient provoking factor in the 2 months before the diagnosis of VTE (estrogen-containing therapy, pregnancy and the postpartum period, leg injury associated with decreased mobility for 3 days or more)

proximal DVT or PE (rather than distal DVT)

persistent risk factors, such as:

active cancer [NB1]
inflammatory bowel disease
autoimmune disorders (eg antiphospholipid syndrome, rheumatoid arthritis)
ongoing immobility

male sex

certain thrombophilias—antithrombin deficiency, protein C or S deficiency [NB2]

Note:

DVT = deep vein thrombosis; PE = pulmonary embolism; VTE = venous thromboembolism (ie DVT or PE)

NB1: Active cancer is defined as patients receiving cancer treatment, those diagnosed with cancer in the past 6 months, or with progressive or advanced disease Lyon, 2022.

NB2: The common thrombophilias—factor V Leiden and prothrombin gene mutation heterozygosity—have very little effect on VTE recurrence rates, and do not influence the decision to use extended anticoagulant therapy. Thrombophilia testing is usually not helpful but can be considered for patients with a strong family history of VTE in a first-degree relative.

Tran, 2019

Table 1. Suggested duration of anticoagulant therapy to treat acute venous thromboembolism
Clinical situation [NB1]	Duration of therapy
Proximal DVT or PE that was unprovoked or associated with a transient (nonsurgical) risk factor DVT or PE associated with active cancer Lyman, 2021	3 to 6 months, followed by consideration of extended therapy
Proximal DVT or PE caused by major surgery or trauma that is no longer present	3 months
Distal DVT that was unprovoked	3 months
Distal DVT caused by a transient provoking factor	6 weeks
DVT = deep vein thrombosis; PE = pulmonary embolism Note: NB1: For a definition of unprovoked DVT or PE and examples of provoking factors, see Common factors predicting recurrence of venous thromboembolism.