Prior to the development of anticoagulant therapy, untreated venous thromboembolism (VTE) was often fatal with up to 30% of cases dying [34]. Anticoagulant therapy effectively treats the symptoms of VTE and decreases recurrent VTE and death, but anticoagulation increases the risk of major haemorrhage, which can be fatal in up to 25% of cases [34]. Understanding the balance of risk and benefit of treatment options helps to inform management decisions [34]. The risk and benefit balance is best evaluated from two perspectives:

The disease phase:

  • Acute (first 5-10 days)
  • Long-term (first 3 months)
  • Extended (beyond 3 months)

The disease aetiology:

  • Initial VTE was provoked (by transient risk factors)
  • Initial VTE was unprovoked
  • VTE was associated with malignancy

The acute and long-term phases are treated the same for provoked and unprovoked VTE. Aetiology becomes relevant for the extended phase; malignancy-associated VTE has different recommendations in all phases of treatment [34].