1st June 2023

Venous thrombosis

Venous thrombosis includes both deep vein thrombosis (DVTs) and pulmonary emboli (PEs). Treatment of confirmed PEs/proximal DVTs is with anticoagulation; the first-line choice in these cases is either apixaban or rivaroxaban. If these medications are not suitable for any reason then low molecular weight heparin (LMWH) should be given for 5 days, then replaced by dabigatran or edoxaban. Alternatively, LMWH can be given alongside warfarin for >5 days (or until the INR is >2 on 2 consecutive readings) and then warfarin can be continued alone.

NICE guidelines for the investigation of unprovoked DVT advise a full medical history and physical examination, and full blood tests should be sent for FBC, U+E, LFTS, PT and APTT.  Patients should not be offered further investigations for cancer unless relevant symptoms or signs are apparent.

If a patient has an unprovoked PE/DVT, their ongoing risk of VTE versus their bleeding risk (e.g. using the HAS-BLED score) is assessed to decide whether anticoagulation should be continued for longer than 3 months (or 6 months for active cancer patients). If the DVT/PE was provoked, healthcare professionals can consider stopping anticoagulation once the patient has completed 3 months (for patients with active cancer, this decision should take place after 3-6 months). Again, the risk vs benefit of anticoagulation should be considered.

Risk factors

Strong risk factors include:

• Thrombophilia
• Trauma
• Following a period of immobility
• Malignancy
• Previous VTE
• Post-surgery

Weaker risk factors include:

• Myeloproliferative diseases, congestive heart failure, COPD, inflammatory bowel disease, some neurological diseases, obesity, increasing age, pregnancy/postnatal period, history of varicose veins, first degree relative with VTE, extended travel, HRT and oestrogen-containing contraceptive pills.