Extended Anticoagulation After Pulmonary Embolism: A Multicenter Observational Cohort Analysis.

Background Pulmonary embolism (PE) has a long-term risk of adverse events, which can be prevented by extended anticoagulation. We compared clinical characteristics and outcomes between patients treated with 2-year extended anticoagulation and those who were not, in a population who had completed an initial phase of 3 to 6 months of anticoagulant therapy after acute PE. Methods and Results Observational cohort analysis of patients with PE who survived an initial phase of 3 to 6 months anticoagulation. Primary efficacy outcome was all-cause death or recurrent venous thromboembolism. Primary safety outcome was major bleeding. In total, 858 (71.5%) patients were treated with and 341 (28.5%) were treated without extended anticoagulant therapy during the active study period. Age <65 years, intermediate-high or high-risk index PE, normal platelet count, and the absence of concomitant antiplatelet treatment were independently associated with the prescription of extended anticoagulation. The mean duration of the active phase was 2.1±0.3 years. The adjusted rate of the primary efficacy outcome was 2.1% in the extended group and 7.7% in the nonextended group ( P <0.001) for patients treated with extended anticoagulant therapy. Rate of bleeding were similar between the extended anticoagulant group and the nonextended group. Conclusions Extended oral anticoagulation over 2 and a half years after index PE seems to provide a net clinical benefit compared with no anticoagulation in patients with PE selected to receive extended anticoagulation. Randomized clinical trials are warranted to explore the potential benefit of extended anticoagulation in patients with PE, especially those with transient provoking factors but residual risk.