RESPECTED-Long: A Retrospective Longitudinal Cross-Sectional Single Centre Study Finds Increasing Emergency...

Increasing ED-CT Pulmonary Angiography (CTPA) use raises concerns about overuse and low yield. CTPA numbers at Sir Charles Gairdner ED were seemingly increasing. This single-site, retrospective, observational study looked for increasing usage over ten years, and whether lower yields suggested over-testing.

Two linked hypotheses: (1) CTPA rates increased over a decade and (2) if CTPA is increasing significantly, yield reduces suggesting overuse. For Hypothesis 1, ED-CTPA per 1000 attendances 2014-2023 were calculated from radiology imaging data. For Hypothesis 2, 2023/24 CTPA results were reviewed for demographics, PE diagnosis, imaging quality, and largest vessel with PE, using similar methods to previous studies. We calculated 700 cases needed reviews if CTPA increased 5%-6% annually (previous regional studies) and yield decreased inversely. Statistical analysis compared rates over time and compared 2012-2013 versus 2023-2024 for Hypothesis 1. For Hypothesis 2, analysis was for difference in proportions for yield (and largest vessel with PE) versus previous 2012-2013 data.

Rates of ED-CTPA increased 65% over 2014-2023 but yield was stable (16.3% vs. 15.7%). PE diagnoses increased by over 60% (1.3-2.1 PE/1000). Large vessel PE (≥ lobar) decreased significantly (59.9%-40.5%), intermediate-vessel PE increased (20%-35.1%), but small vessel PE was unchanged (19.2 vs. 24.3%). Women ≤ 50 years had significantly lower yield (5.4%).

CTPA use increased markedly, without expected decreased yield. Increased PE diagnosis rates suggest maintained diagnostic discrimination. Large vessel PE proportions reduced, but small PE rates didn't increase significantly. Younger women seem over-investigated with low yield (5.6%) versus all other groups.