Grant: Travel Awards - Institute Community Support

Venous thromboembolism (VTE) is a series of conditions where a blood clot forms in a patient's veins. VTE is the third most common cardiovascular disorder in the world, with pulmonary embolism - the most severe form of VTE - being the third most common cause of cardiovascular death overall. About half of cases of VTE are unprovoked, with no clear contributory factor that led to the diagnosis. Blood thinners, or anticoagulants, are the mainstay of treatment for VTE. While highly effective, bleeding is their most common and serious complication. In patients with unprovoked VTE, decision-making around how long patients should be treated requires balancing the risk of another clot from forming, with the risk of bleeding while on anticoagulation. We sought to analyze whether a patient's D-dimer level - a blood test that is often measured to screen whether patients might have a VTE - might predict the risk of major bleeding. We analyzed two large studies of individuals with unprovoked VTE, who continued anticoagulation after 3 months of initial treatment. We found that individuals with higher on-treatment D-dimer levels were nearly five times more likely to experience major bleeding compared to those with the lowest on-treatment D-dimer levels. This remained consistent after we adjusted for age, sex, and anticoagulant type across the two groups. We demonstrate that D-dimer levels may be a useful measure to determine the risk of a patient experiencing major bleeding while on extended anticoagulation treatment for unprovoked VTE. This underscores the need to personalize anticoagulant duration in unprovoked VTE to optimize their benefit while reducing the risk of complications.