Diagnostic Performance of Pulmonary Embolism Imaging in Patients with History of Asthma

Asthma and pulmonary embolism (PE) can present with overlapping symptoms, and distinguishing between these 2 conditions can be challenging. Asthma may limit imaging for PE because of either worsened ventilation defects on ventilation-perfusion scanning (VQ) or increased motion artifacts on CT pulmonary angiography (CTPA). Methods: We identified adults evaluated for PE with VQ or CTPA from 2012 to 2016. Patients with chronic lung disease (other than asthma) were excluded. Studies were classified as negative, positive, or nondiagnostic. Follow-up of negative cases was reviewed to determine the rate of repeat exams (within 1 wk) and the false-negative rate (defined as diagnosis of venous thromboembolism within 90 d). Results: We reviewed 19,412 adults (aged 52 ± 18 y, 70% women) evaluated for PE (60% with VQ, 40% with CTPA); 23% had a history of asthma. Nondiagnostic results were comparable for those with and without asthma for both VQ (asthma, 3.3%; nonasthma, 3.8%; P = 0.223) and CTPA (asthma, 1.6%; nonasthma, 1.5%; P = 0.891). A history of asthma was not associated with a higher rate of repeat exams after negative imaging for VQ (asthma, 1.9%; nonasthma, 2.1%; P = 0.547) or CTPA (asthma, 0.6%; nonasthma, 0.6%; P = 0.796), nor was a history of asthma associated with a higher false-negative rate for VQ (asthma, 0.4%; nonasthma, 0.9%; P = 0.015) or CTPA (asthma, 1.9%; nonasthma 1.5%; P = 0.347). Conclusion: A history of asthma in the preceding 10 y was not associated with impaired diagnostic performance of PE imaging for either VQ or CTPA.