Time-to-Start of Anticoagulant Therapy and Mortality in Pulmonary Embolism

BACKGROUND: Pulmonary embolism (PE) is a significant cause of mortality. Prior studies indicate initiation of anticoagulant therapy in the emergency department (versus after admission) could decrease mortality. Therefore, time-to-start of anticoagulant therapy may be a modifiable risk factor contributing to PE-related mortality. OBJECTIVES: We aimed to quantify the association between delay in the time from presentation with symptoms of acute PE to start anticoagulant therapy with the risk of PE-related mortality. PATIENTS/METHODS: We conducted a multi-center, retrospective cohort study of patients presenting with acute intermediate- or high-risk PE who received initial treatment with low-molecular-weight or unfractionated heparin from 6/2020-9/2024. Logistic regression quantified the association between 30-day PE-related mortality and time from presentation to anticoagulant initiation. RESULTS: 562 patients met inclusion criteria. 11% (n=64) died within 30-days from a PE-related cause. The geometric mean time from acute care presentation to start of anticoagulant therapy was 225 minutes in survivors versus 284 minutes in those who died (p=0.067). Controlling for PE severity, simplified pulmonary embolism severity index (sPESI), renal function, thrombectomy, and anticoagulant type, each doubling in time to anticoagulant therapy start had a 1.38-fold increased odds of PE-related death (95% CI: 1.05-1.82, p=0.021). Among intermediate-risk patients (n=434), each doubling in time to anticoagulant therapy start had a 2.4-fold increased odds of PE-related death (95% CI: 1.44-3.96, p<0.001). CONCLUSIONS: In patients presenting to the acute care setting with intermediate- or high-risk PE, delay in start of anticoagulant therapy was independently associated with increased odds of PE-related mortality. Quality improvement initiatives reducing time-to-start of anticoagulant therapy are warranted.