Risk stratification for recurrent venous thromboembolism in unprovoked venous thromboembolism patients

Unprovoked venous thromboembolism (VTE) patients are at much higher risk of a recurrent VTE event than provoked VTE patients. Oral anticoagulation therapy (OAT) after a first unprovoked VTE has proved to effectively reduce the risk of recurrence during therapy however this benefit is lost after discontinuing OAT. A minimum of 6 to 12 months of OAT is recommended for first unprovoked VTE patients to prevent recurrence. However, there is evidence indicating that some patients are at ongoing high risk of recurrent VTE after discontinuation of therapy and that these patients may need indefinite anticoagulation to effectively prevent recurrences. Several risk factors for recurrent VTE have been identified that may be helpful to physicians when deciding whether OAT should be continued or discontinued in unprovoked VTE patients after initial therapy. The present article reviews risk factors for recurrent VTE including D-Dimer levels after discontinuation of OAT, elevated levels of Factor VIII, residual venous obstruction, post-thrombotic syndrome, male gender, and older age. Research is also underway to determine the predictive ability of these known VTE recurrence risk factors, combinations of these risk factors and their interrelationships as well as to actively search for additional potential predictors.