Approach to VTE treatment

Anticoagulant therapy is indicated for the treatment of most cases of venous thromboembolism (VTE) (ie deep vein thrombosis [DVT] or pulmonary embolism [PE]) because it is highly effective in preventing thrombus extension and recurrence.

Before starting anticoagulant therapy, collect blood to measure the patient’s activated partial thromboplastin time (APTT), international normalised ratio (INR), full blood count, kidney function and liver biochemistry. Perform a serum beta human chorionic gonadotrophin (hCG) test for patients of childbearing potential. More extensive testing is rarely indicated.

To provide appropriate treatment, determine whether the reported site of the thrombus is a deep or superficial vein. For a list of the major deep and superficial veins of the lower and upper limbs, see Major deep and superficial veins of the lower and upper limbs.

Treatment of DVT depends on its anatomical extent, which must be determined by imaging with compression ultrasound. In proximal DVT of the lower limbs, the thrombus is present in the popliteal or a more proximal deep vein. In distal DVT of the lower limbs, the thrombus only occurs in deep veins distal to the popliteal vein.

For upper-limb and lower-limb proximal DVT, or PE, use anticoagulant therapy (unless the patient has an absolute contraindication). Anticoagulant therapy effectively reduces the incidence of death in patients with PE and decreases the likelihood that PE will occur in patients with proximal DVT.

There is less evidence to guide treatment of distal lower-limb DVT; anticoagulant therapy is the favoured treatment, but compression ultrasound surveillance is an alternative for carefully selected patients. See Approach to treatment of distal lower-limb deep vein thrombosis for more information.

VTE can occur at sites other than the lower limb (eg axillary or subclavian vein thrombosis, splanchnic vein thrombosis)—for advice on management, see VTE at sites other than the lower limb.

Direct-acting oral anticoagulants (DOACs) are the preferred anticoagulants for the acute treatment of VTE in most patients. Warfarin is the preferred oral anticoagulant in patients with concomitant severe kidney impairment or another indication for warfarin (eg antiphospholipid syndrome). Parenteral anticoagulants are preferred for the acute treatment of VTE in pregnant or breastfeeding patients and patients with severe kidney impairment or decompensated cirrhosis.

The duration of anticoagulant therapy is influenced by the presence or absence of provoking factors, the patient’s risk factors for recurrence of VTE or bleeding, and patient preference. Extended therapy can be considered for some patients.

Thrombolytic therapy and interventional procedures are used in addition to anticoagulant therapy for some haemodynamically unstable patients with PE, and for some patients with DVT.

Post-thrombotic syndrome can occur in patients with DVT despite anticoagulant therapy (see Post-thrombotic syndrome). For patients with proximal DVT, seek specialist advice regarding thrombolytic therapy and interventional procedures.

Superficial vein thrombosis can be complicated by VTE or thrombus extension, so anticoagulant therapy may be warranted—see Superficial vein thrombosis for an approach to management.

For information on the use of anticoagulants in patients who are undergoing surgery or a procedure, see Periprocedural management of antithrombotic therapy.

The use of anticoagulants in patients with palliative care needs can be complex; the risk of developing VTE, the burden of treatment and the goals of care must be considered when preventing or treating thromboembolic events while minimising the bleeding risk. See Venous thromboembolism in the Palliative care guidelines for more information.