# The Effect of Early Anticoagulation Therapy in Acute Pulmonary Embolism: A Retrospective Cohort Study in the Emergency Department

## TL;DR

Starting anticoagulation within two hours of emergency department arrival for acute pulmonary embolism improves survival and reduces hospital stay without increasing bleeding risk.

## Contribution

Demonstrates the clinical benefits of early anticoagulation in acute pulmonary embolism within a real-world emergency department setting.

## Key findings

- Early anticoagulation reduced in-hospital mortality from 17.0% to 7.3%.
- Early treatment decreased ICU admissions and hospital stay by nearly 3 days.
- No significant increase in major bleeding events was observed with early anticoagulation.

## Abstract

Background: Acute pulmonary embolism (PE) is a critical emergency condition that can lead to rapid hemodynamic compromise and death if not treated promptly.

Objective: To assess whether initiating anticoagulation within two hours of emergency department (ED) presentation improves in-hospital outcomes in patients with acute pulmonary embolism.

Methods: This retrospective cohort study was conducted at Fauji Foundation Hospital, Rawalpindi, from December 2024 to June 2025. A total of 345 adult patients diagnosed with acute PE between January 2020 and December 2024 were included. Patients were divided into two cohorts: early anticoagulation and delayed anticoagulation (initiated after four hours). Clinical data, including demographics, comorbidities, hemodynamic parameters, laboratory findings, imaging results, and treatment outcomes, were analyzed.

Results: Out of 345 patients, 192 (55.6%) received early and 153 (44.4%) delayed anticoagulation. The mean age was 54.8 ± 15.2 years, with 215 (62.3%) males. Mortality was significantly lower in the early group, 14 patients (7.3%), compared to 26 patients (17.0%) in the delayed group (p = 0.006). Early anticoagulation also reduced recurrent thromboembolism, occurring in seven patients (3.6%) versus 14 patients (9.2%) in the delayed group (p = 0.03), as well as ICU admissions-47 patients (24.5%) versus 59 patients (38.6%), respectively (p = 0.008). The mean hospital stay was significantly shorter in the early group (5.8 ± 2.9 days) than in the delayed group (8.4 ± 3.6 days, p < 0.001). No significant difference in major bleeding events was observed between groups (p = 0.48).

Conclusion: It is concluded that initiating anticoagulation within two hours of presentation significantly improves survival, decreases recurrence, and shortens hospital stay without increasing bleeding risk. Emergency departments should prioritize rapid diagnostic and treatment pathways to enable early anticoagulation, particularly in resource-limited settings.