Acute Pulmonary Embolism: A Comprehensive Overview of Pathophysiology, Diagnosis, Risk Stratification, and Evidence-Based Management

Acute pulmonary embolism (PE) remains a major cardiovascular emergency and a leading cause of preventable in-hospital mortality worldwide. As the third most common acute cardiovascular syndrome after myocardial infarction and stroke, PE imposes a substantial burden on healthcare systems. This comprehensive review synthesizes current evidence on the etiology, pathophysiology, clinical presentation, diagnostic evaluation, and management of acute PE, with an emphasis on risk-stratified, guideline-directed care.

PE most commonly arises from lower-extremity deep vein thrombosis, with the classic Virchow triad of hypercoagulability, venous stasis, and endothelial injury providing a durable conceptual framework for understanding thrombotic risk. The clinical presentation is notoriously nonspecific—ranging from subtle dyspnea to sudden cardiac death—which continues to make timely diagnosis a daily challenge in emergency medicine and inpatient care. Missed or delayed diagnosis carries grave consequences: untreated PE carries a mortality of approximately 30%, whereas prompt, appropriate therapy reduces that figure to around 8%.

Modern diagnostic strategies integrate clinical probability assessment using validated tools such as the Wells criteria and Geneva score with D-dimer testing and definitive imaging, most commonly computed tomographic pulmonary angiography. Risk stratification into high-risk (hemodynamically unstable), intermediate-risk (submassive, with right ventricular dysfunction or biomarker elevation), and low-risk categories is the essential first step in management. Anticoagulation remains the cornerstone of treatment for all patients without contraindications. For high-risk PE, systemic thrombolysis or mechanical reperfusion (catheter-directed or surgical embolectomy) can be life-saving, though these interventions carry important bleeding risks that must be weighed carefully.

Long-term management requires individualized decisions regarding the duration of anticoagulation, balancing the risk of recurrent venous thromboembolism against bleeding risk. Unprovoked PE and persistent risk factors such as active cancer generally warrant extended therapy. The emergence of pulmonary embolism response teams has improved interdisciplinary coordination and outcomes. This review provides clinicians with a practical, evidence-based framework for recognizing, risk-stratifying, and managing acute PE across the spectrum of disease severity.