High-risk pulmonary embolism: Risk stratification and criteria for thrombolysis

Abstract

High-risk pulmonary embolism is a time-critical form of venous thromboembolism in which acute right ventricular failure can progress rapidly from compensated obstruction to shock and cardiac arrest. This narrative review examines how contemporary risk stratification should guide systemic thrombolysis and how bleeding risk modifies reperfusion decisions. A structured literature search conducted in 2026 used PubMed/MEDLINE together with current American Heart Association/American College of Cardiology, European Society of Cardiology, and CHEST guidance, prioritizing guidelines, randomized trials, meta-analyses, registries, and interventional consensus documents. The evidence supports defining high risk by cardiopulmonary consequences rather than clot location or radiological burden alone. Persistent hypotension, obstructive or cardiogenic shock, hypoperfusion, and cardiac arrest identify the groups most likely to require immediate reperfusion. Systemic thrombolysis remains a rapid and widely available option when life-threatening instability is present and bleeding risk is acceptable, whereas routine primary thrombolysis in normotensive patients is not supported because the reduction in hemodynamic deterioration is offset by major and intracranial bleeding. Patients with incipient failure require individualized escalation. When systemic fibrinolysis is contraindicated or unsuccessful, catheter-based therapy, mechanical throm bectomy, surgical embolectomy, and selected mechanical circulatory support should be considered without delaying definitive reperfusion.