Anticoagulation for Patients with Venous Thromboembolism: When is Extended Treatment Required?

Abstract

The need for extended venous thromboembolism (VTE) treatment beyond 3 to 6 months is usually determined by balancing the risk of recurrence if treatment is stopped against the risk of bleeding from continuing treatment. The risk of recurrence, and in turn the decision to extend, can be determined through the nature of the index event. Patients with VTE provoked by surgery or trauma (major transient risk factors) are recommended to receive 3 months of anticoagulation therapy because their risk of recurrence is low, whereas patients with VTE provoked by a major persistent risk factor, such as cancer, or those considered to have "unprovoked" VTE, are recommended to receive an extended duration of therapy based on an established high risk of recurrence. Nonetheless, recent evidence and new guidance identify that this approach fails to consider patients with risk factors classed as minor transient (e.g., impaired mobility and pregnancy) or minor persistent (e.g., inflammatory bowel disease and congestive heart disease). Indeed, the risk of recurrence with respect to VTE provoked by minor persistent risk factors has been demonstrated to be not dissimilar to that of VTE without identifiable risk factors. This review provides an overview of the available data on the risk of recurrence according to the underlying cause of VTE, a critical evaluation of evidence from clinical studies on the available anticoagulants for extended VTE treatment, models of risk prediction for recurrent VTE and bleeding, and guidance on how to apply the evidence in practice.

Keywords: anticoagulants; recurrence; risk assessment; risk factors; venous thromboembolism.

Fig. 1

Decision tree for continued anticoagulation in patients with VTE. ^a Major persistent conditions include active cancer and antiphospholipid antibody syndrome. ^b Minor persistent defined as inflammatory bowel disease, lower extremity paralysis or paresis, congestive heart failure, BMI >30 kg/m ² , creatinine clearance <50 mL/min, family history of VTE, hereditary thrombophilia and acquired thrombophilia. Minor transient defined as immobilization, travel >8 hours and leg injury with impaired mobility. BMI, body mass index; DVT, deep vein thrombosis; HERDOO2, Hyperpigmentation, Edema, or Redness in either leg; D-dimer level ≥ 250 μg/L; Obesity with body mass index ≥ 30; or Older age, ≥ 65 years; VTE, venous thromboembolism.