Prevalence of pulmonary embolism among patients with recent onset of dyspnea on exertion. A cross-sectional study

Background: Exertional dyspnea is a frequently encountered complaint in clinical practice. However, the prevalence of pulmonary embolism (PE) among patients with dyspnea on exertion has not been reported. Objective: The objective of this study was to assess the prevalence of objectively confirmed PE among consecutive patients visiting an emergency department because of recent onset of exertional dyspnea. Methods: Patients aged <= 75 years with recent (<1 month) marked exertional dyspnea had a systematic workup for PE, irrespective of concomitant signs or symptoms of venous thromboembolism and alternative explanations for dyspnea. PE was excluded on the basis of a low pretest clinical probability and normal age -adjusted D-dimer. All other patients had computed tomography pulmonary angi-ography. An interim analysis after inclusion of 400 patients would stop recruit-ment if the 95% confidence interval (CI) of the PE prevalence had a lower limit exceeding 20%. Results: The study was prematurely terminated after the inclusion of 417 patients. In 134 patients (32.1%), PE was excluded based on low clinical probability and normal D-dimer. PE was found in 134 (47.3%) of the remaining 283 patients, for an overall prevalence of 32.1% (95% CI, 27.8-36.8). PE was present in 40 of 204 (19.6%) patients without other findings suspicious for PE and in 94 of 213 patients (44.1%) with such findings. PE involved a main pulmonary artery in 37% and multiple lobes in 87% of the patients. Conclusion: The angiographic demonstration of PE is common in patients presenting with recent onset of marked exertional dyspnea, including 20% without other findings suggesting pulmonary embolism.