D-dimer has high sensitivity for acute pulmonary embolism (PE) diagnosis, but poor specificity – resulting in unnecessary imaging and costs. Age-adjusted (AADD), clinical probability-adjusted (CPADD) and YEARS-algorithm-adjusted (YDD) D-dimer approaches increase specificity, but their relative effectiveness is unclear.

To assess the diagnostic effectiveness of AADD, CPADD, YDD, clinician judgement and novel approaches, and estimate potential cost-savings from the best-performing approach.

Retrospective cross-sectional analysis of consecutive patients attending Canberra Hospital Emergency Department from December 2019–March 2020 with Computerised Tomography Pulmonary Angiography (CTPA) and D-dimer performed for suspected PE. Sensitivities/specificities of approaches were compared. Proportion of avoidable CTPAs and annual cost-savings were calculated using the best-performing approach. 

226 patients (mean age 59.1 years; 61.1% female) were included, with PE diagnosed in 10.6% on CTPA. CPADD (95.8% sensitivity; 62.9% specificity) and YDD (100% sensitivity; 57.4% specificity) were superior to AADD (95.8% sensitivity; 28.7% specificity) and 0.5 mg/L cut-off (100% sensitivity; 16.8% specificity). Clinician judgement had high specificity (79.2%) but poor sensitivity (58.3%). Novel combined approaches using YDD and CPADD with 0.75 mg/L and 1.40 mg/L optimised cut-offs (YDD 0.75/1.40 and CPADD 0.75/1.40) had highest sensitivity and specificity (YDD 0.75/1.40 100% sensitivity, 74.8% specificity; CPADD 0.75/1.40 95.8% sensitivity, 78.7% specificity). YDD 0.75/1.40 approach would have avoided 45.8% of all CTPAs – equating to AUD$253,405 annual cost-savings, with zero missed PEs.

YDD, CPADD and the novel approaches are most effective – potentially avoiding half the CTPAs and saving a quarter-million dollars annually at Canberra Hospital.

Utilising novel D-dimer approaches can potentially improve PE diagnosis and reduce healthcare resource utilisation.

 

Yi Tong Vincent Aw1,2,3, Jessica YH Aw3, Priyaah Sekar4, Teisa Holani5, Craig Wayling4, Hsien Cheun Soo4, Denesh Selvarajah4, Stuart Schembri6,3
 
 

1.     General Medicine Department, Canberra Health Services, Garran, ACT 2605

2.     College of Health and Medicine, The Australian National University, ACT, 2601

3.     ANU Medical School, The Australian National University, Acton, ACT, 2605

4.     Canberra Health Services, Garran, ACT, 2605

5.     Emergency Department, Calvary Public Hospital, Bruce, ACT, 2617

Department of Respiratory and Sleep Medicine, Canberra Health Services, ACT, 2605