Predicting the risk of recurrence of venous thromboembolism

Purpose of review Although several clinical studies have investigated the effects of different treatment periods in subjects after a VTE event, the optimal duration of oral anticoagulation is still uncertain. Our review focused on studies that evaluated different risk factors that might be useful to stratify patients into categories at different risk for recurrence. Recent findings The presence of irreversible, persistent, or transient risk factors affects the risk of recurrence. The inherited and acquired thrombophilic conditions that are associated with an increased risk of VTE may also be responsible for an increased risk of recurrence. Although this is still a matter of debate for the more common alterations, it is accepted for antithrombin, protein C, protein S deficiency, homozygous factor V Leiden, double heterozygosity, and antiphospholipid syndrome. It has been shown that high factor VIII levels are associated to increased risk of VTE recurrence. The presence of cancer is one of the most important persistent factors associated with VTE. Several studies have recently shown that D-dimer levels measured during and especially after oral anticoagulation interruption in subjects with a previous VTE, carriers or not of congenital thrombophilia have a high NPV for recurrence. The relation between the persistence of residual venous thrombosis and the risk of VTE recurrence has been investigated in two recent studies and both concluded that the persistence of a residual venous thrombosis is an important risk factor for recurrent thromboembolism and that its assessment may help clinicians modify the duration of anticoagulation in patients with DVT. Summary Both the clinical aspects of the first VTE event and individual characteristics (such as associated diseases, inherited or acquired thrombophilic conditions, altered D-dimer results, or the presence of residual venous thrombosis) concur in determining the recurrence risk of each patient. Whether the evaluation of these risk factors may help to tailor the secondary prevention treatment in each patient should be assessed by specifically designed intervention studies.