Pulmonary Embolism as a Cause of COPD Exacerbations

Inclusion Criteria: * Confirmation of COPD according to SEPAR-ALT criteria: post-bronchodilator forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) \< 0.7; * Hospital admission because COPD exacerbation without initial clinical suspicion of PE in the Emergency Department (according by the Emergency Department physician evaluation). Exclusion Criteria: * Contraindication to multidetector computed tomographic angiography (allergy to intravenous contrast medium, or renal failure defined as a creatinine clearance less than 30 mL/min, according to the Cockcroft-Gault formula) * Informed consent denied * Pregnancy * Life expectancy less than 3 months * Anticoagulant therapy at the time of hospital admission * Diagnosis of pneumothorax, or pneumonia (fever, and purulent sputum, and new infiltrate in chest X-ray) * Diagnosis of lower respiratory tract infection (fever \[\>37.8ºC\], increased sputum volume and/or increased sputum purulence). * Indication of invasive mechanical ventilation at the time of hospital admission; * Impossibility for follow-up.