Impact of Early versus Late Intervention on Outcomes for Acute Pulmonary Embolism

Objectives While anticoagulation is standard for most patients with pulmonary embolism (PE), those with intermediate- or high-risk submassive PE may benefit from advanced therapies such as percutaneous mechanical thrombectomy (PMT). Although early intervention has been advocated in the surgical era, its role in percutaneous strategies remains uncertain, with no consensus definition of "early" intervention. We examine the association between time-to-intervention and patient outcomes following PMT for submassive PE. Methods We conducted a retrospective review of patients aged 18–100 years who underwent PMT for acute PE at a single tertiary cardiovascular hospital between January 2023 and December 2024. Diagnosis was confirmed by CT pulmonary angiography, echocardiography, hemodynamic monitoring, & hematologic biomarkers (e.g., troponin, BNP). Patients were stratified using PESI score classification. Device selection was at the discretion of the proceduralist (vascular surgeon or interventional cardiologist). Time-to-intervention was defined as the interval from emergency department admission to procedure start time and was stratified into three categories (early; 0-6 hours, mid; 7 – 24 hours, or late; >24 hours). Primary outcome was in-hospital mortality; secondary outcomes included hospital length of stay, 30-, 180- and 360-day mortality. Results A total of 148 patients met inclusion criteria. Median time-to-intervention was 20.8 hours. There was no significant difference in baseline demographics between the 3 treatment groups. There was a total of 3 (2.1%) in-hospital mortality events, with no statistically significant difference for in-hospital mortality between all three categories (early 0%, mid 4.7%, late 0 %, p = [0.2065]). There was no additional mortality difference at 30 days, 6 months, or 12 months in any of the treatment groups. Early intervention group had statistically significantly higher PESI scores, troponin & BNP values, and right heart strain on echo, without a change in clinical outcomes. The only statistically significant difference in outcome was in length of stay (LOS). Median LOS for the late cohort was 4 days, while only 2 and 2.5 days for the early and middle cohorts resulting in a statistical difference only between the early and late groups respectively, (p=0.0164). Conclusions In this single-center retrospective study, early intervention with PMT for acute PE was not associated with improved mortality, although treatment >24 hours extended the hospital length of stay. These findings suggest that patient outcomes are not dependent on early intervention and may rely more on patient selection and procedural efficacy, underscoring the need for prospective trials to clarify the role of time-to-intervention in PMT.