Seven-year trends in computed tomography (CT) pulmonary angiography utilisation and predictors of positivity in a large emergency department.

Abstract

<h4>Aim</h4>To evaluate trends in computed tomography pulmonary angiography (CTPA) utilisation in an emergency department (ED) and identify factors associated with pulmonary embolism (PE) detection.<h4>Materials and methods</h4>This retrospective study analysed CTPA exams from 2017-2023 at a quaternary urban ED. CTPA volumes were normalised to total ED visits and ED CTs. Logistic regression assessed predictors of positivity. CTPA-per-visit trends were modelled with negative-binomial regression.<h4>Results</h4>CTPA volume rose 49% from 2,467 in 2017 to 3,684 in 2023. Positivity rates remained stable (mean 9.1%, range 8.3%-10.6%, p=0.55). CTPA use peaked at 10.0% of ED CTs in 2021, declining to 8.3% by 2023 (p=0.30). CTPAs per 1,000 ED visits increased from ∼22 in 2017 to ∼40 in 2021, then fell to ∼31 in 2023 (p=0.75). Male patients had higher odds of a positive result (aOR 1.222, 95% CI: 1.115-1.339), as did Black (aOR 1.222, CI: 1.058-1.412) vs White patients. Asian patients had lower odds (aOR 0.647, CI 0.489-0.857). Overnight exams were less likely to yield PE (aOR 0.830, CI 0.730-0.945). Higher body mass index (BMI) (aOR 1.014, CI 1.006-1.022) and cancer history (aOR 1.185, CI 1.039-1.352) were also predictive. Ordering provider training level (MD/DO, NP, PA) did not affect diagnostic yield.<h4>Conclusion</h4>Over a seven-year period (2017-2023), annual CTPA volume and utilisation rate increased, but the positivity rate remained stable at ∼9%. Male sex, Black race, higher BMI, cancer history, and daytime imaging were associated with higher odds of PE. Provider training level was not associated with diagnostic yield.