Yield of chest computed tomography angiogram in cystic fibrosis patients with suspected pulmonary embolism

INTRODUCTION: Individuals with cystic fibrosis (CF) may be at increased risk of pulmonary embolism (PE). Symptoms of PE overlap substantially with those of CF respiratory exacerbations. CF patients commonly undergo chest computed tomography (CT) angiograms (CTPA) to evaluate for PE, but little is known about the clinical presentation and diagnosis of PE in this population. OBJECTIVES: The objectives of this study are to determine the diagnostic yield of CTPA for PE in adult patients with CF and assess the utility of the Revised Geneva Score (RGS) in this population. METHODS: Retrospective review of all CTPA results was performed on CF patients with suspected PE at a large CF center from 1 January 2011 through 31 March 2017. Patient demographics, medical history, and presenting signs and symptoms were abstracted by chart review. RESULTS: A total of 103 unique CTPA studies were performed in 68 patients. Most were hospitalized at the time of CTPA, predominantly for respiratory manifestations of CF. CTPA identified four patients with PE. The small number of positive studies precluded analysis of predictors of PE. Fewer PE were diagnosed than predicted by the Revised Geneva Score, which was intermediate probability in 77/103 (75%) patients. CONCLUSION: The prevalence of PE in CF patients undergoing CTPA for suspected PE was 4%, which is lower than predicted by the Revised Geneva Score. This may be due to a large overlap in the signs and symptoms of PE and exacerbations of CF lung disease.