Risk stratification is one of the cornerstones of the management of acute pulmonary embolism (PE) and may affect the choice of both diagnostic and therapeutic strategies. Critical steps requiring risk stratification in patients with acute PE include identification of patients at very high risk of early mortality requiring immediate diagnostic and rescue therapies; identification of patients at low-risk of complications who can be treated as outpatients and identification of normotensive patients with an increased risk of complications requiring reperfusion therapy or close monitoring.