Objective Choosing Wisely Australia was launched in 2015 to reduce unnecessary investigations and treatments. This study attempts to reduce over-testing (and thereby minimise incidental findings) with computerised tomography pulmonary angiography (CTPA) in patients presenting to the emergency department (ED) of Northern Hospital in Victoria, Australia.

Methods Records of 358 patients who had CTPA at Northern Health ED were collected from 1st July to 31st October 2017 as a pre-implementation cohort. A clinical decision pathway, following a protocol validated at Melbourne Eastern Health, published by Buntine et al. (1), that included Wells score, PERC and D-dimer was applied retrospectively to test justification for the use of CTPA in these patients. The same pathway was implemented in February 2019 at Northern Health for patients presenting to the ED with suspected pulmonary embolus. Audit was repeated for the 260 patients who underwent CTPA between 1st March to 31st May 2019. Implementation involved staff education, appropriateness monitoring and CTPA ordering changes. IBM SPSS Statistics 25 was used to conduct univariate as well as manual back-step multivariate logistic regression analysis.

Results CTPA imaging yield (percentage positive) increased from 7.26% to 11.54% (p = 0.07). CTPA imaging rate decreased from 1.10% to 0.94% (p = 0.06). CTPA appropriateness increased from 29.05% to 64.23% (p<0.01). Appropriate CTPAs had a yield of 14.39% compared to 4.90% of inappropriate CTPAs (p<0.01). An appropriate CTPA had a 3.20 odds ratio for positive CTPA (p<0.01) on multivariate logistic regression analysis.

Conclusion Pathway use has been associated with a change of practice. Although improvements in imaging yield and rate were not statistically significant, appropriately ordered CTPAs had a significant odds ratio for positive CTPA. Northern Health ED is one of the busiest in the country with significant access block. This may have contributed to clinicians ordering inappropriate CTPAs instead of waiting for D-dimer results, which reduced the effectiveness of the intervention. Continued pathway use will further reduce unnecessary imaging to improve patient care, reduce unnecessary radiation exposure and minimise incidental findings.

Reference

1. Buntine P, Thien F, Stewart J, Woo YP, Koolstra M, Bridgford L, et al. Effect of a clinical flowchart incorporating Wells score, PERC rule and age-adjusted D-dimer on pulmonary embolism diagnosis, scan rates and diagnostic yield. Emergency Medicine Australasia: EMA. 2018.