Outpatient diagnosis of pulmonary embolism: the MIOPED (Manchester Investigation Of Pulmonary Embolism Diagnosis) study

Background and objectives: Pleuritic chest pain, a symptom of pulmonary embolism, is a common presenting symptom in the emergency department. The aim of this study was to validate an algorithm for the diagnosis of pulmonary embolism in emergency department patients with pleuritic chest pain. Methods: This was a prospective, diagnostic cohort study conducted in a large UK city centre emergency department. A total of 425 patients with pleuritic chest pain presenting to the emergency department between February 2002 and June 2003 were recruited. Patients scoring a low modified Wells clinical probability of pulmonary embolism, who had a normal latex agglutination D-dimer, were discharged. All others followed a diagnostic imaging protocol to exclude and diagnose pulmonary embolism using PIOPED interpreted ventilation-perfusion scanning, CT pulmonary angiography, and digital subtraction pulmonary angiography. All patients were followed up for three months for evidence of pulmonary embolism or deep vein thrombosis. An independent adjudication committee reviewed all deaths. Results: A total of 408 patients completed the diagnostic algorithm; 86.5% (353/408) were investigated as outpatients, 5.4% (22/408) were diagnosed as having pulmonary embolism, and 98.8% (403/408) were followed up for three months. Of the 381 patients without pulmonary embolism who completed follow up, the incidence of thromboembolic disease was 0.8% (95% CI 0.3% to 2.3%): two patients had pulmonary embolism and one had a deep vein thrombosis. Conclusions: The MIOPED ( Manchester Investigation Of Pulmonary Embolism Diagnosis) diagnostic protocol can safely exclude pulmonary embolism in outpatients with pleuritic chest pain.