Abstract
Background Both the YEARS algorithm and the pulmonary embolism (PE) rule-out criteria (PERC)
were created to exclude PE with limited diagnostic tests. A diagnostic strategy combining
both scores might save additional computed tomography pulmonary angiography (CTPA)
scans, but they have never been evaluated in conjunction.
Aim The aim of this study was to determine the safety and efficiency of combining YEARS
and PERC in a single diagnostic strategy for suspected PE.
Methods The PERC rule was assessed in 1,316 consecutive patients with suspected PE who were
managed according to YEARS. We calculated the absolute difference (with 95% confidence
interval [CI]) in failure rate and the number of ‘saved’ CTPAs for the scenario that
PE would have been ruled out without CTPA in the absence of all PERC items.
Results Using the YEARS algorithm, PE was diagnosed in 189 patients (14%), 680 patients (52%)
were managed without CTPA and the 3-month rate of venous thromboembolism in patients
in whom PE was ruled out was 0.44% (95% CI: 0.19–1.0). Only 6 of 154 patients (3.9%;
95% CI: 1.4–8.2) with no YEARS items who were referred for CTPA would have been PERC
negative, of whom none were diagnosed with PE at baseline or during follow-up (0%;
95% CI: 0–64). Applying PERC before YEARS in all patients would have led to a failure
rate of 1.42% (95% CI: 0.87–2.3%), 0.98% (95% CI: 0.17–1.9) more than shown in patients
managed by YEARS.
Conclusion Combining YEARS with PERC would have yielded only a modest improvement of efficiency
in patients without a YEARS item and an unacceptable failure rate in patients with
≥ 1 YEARS item.
Keywords
pulmonary embolism - diagnosis - PERC - clinical decision rule - pulmonary embolism
rule-out criteria
