PEDIS Study is an observational, cross-sectional, multicenter Italian study conducted in a consecutive series of patients who refer to the Emergency Departments (either spontaneously or sent by their attending physicians) for the recent (less than one months) development of exertional dyspnea.

The general aim of the study is to assess the prevalence of PE in the overall population referring to the Emergency Departments without potential explanations for dyspnea

PEDIS Study is an observational, cross-sectional, multicenter and no Profit Study.

600 consecutive patients referring to the Emergency Departments of the participating centers because they have developed one or more episodes of exertional dyspnea since less than one month will be enrolled. All eligible patients will be interviewed and examined by trained study physicians. The presence of already known potential explanations for the dyspnea will be assessed. In addition, symptoms of the lower extremities will be elicited, as well as the presence of risk factors for venous thromboembolism (VTE).

The presence or absence of pulmonary embolism will be assessed with the use of a validated algorithm based on pre-test clinical probability and D-dimer result. In patients in whom the pre-test clinical probability is low and the D-dimer result is negative, no further testing will be done, and PE will be considered excluded. In patients with high clinical probability, positive D-dimer result, or both, computed tomography (CT) pulmonary angiography will be performed

The primary study objective is to evaluate Prevalence of PE in the overall population

Inclusion Criteria:

• Age older than 18 and younger than 75
• Recent (less than one month) development of exertional dyspnea
• Able to provide informed consent

Exclusion Criteria:

• Anticoagulation required for other indications
• Contraindication to CT angiography (allergy to the contrast dye, severe renal failure [creatinine clearance < 30 ml/min])
• Involvement in simultaneous clinical trials
• Unable to provide their written informed consent

All consecutive patients who refer to the Emergency Departments of the participating centers will be eligible for the study provided they are older than 18 and younger than 75 years, and have developed one or more episodes of exertional dyspnea since less than one month.