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Retrospective application of the YEARS algorithm to an ambulatory PE clinic cohort

Background: Despite routine use of the Wells score and D-Dimers (DD), high proportions of CTPAs are negative, increasing unnecessary exposure to the risks of CT contrast and radiation. Variable presentation and high perceived risk of missed PEs makes risk stratification complex. The YEARS algorithm offers a more specific tool to reduce the number of CTPAs performed without increased risk. Methods: This audit applied the YEARS algorithm to ambulatory patients who had undergone CTPA for suspected PE, treated based on Wells score and DD. Patients were stratified as either high or low risk by the presence of any one of the YEARS items: clinical signs of DVT, PE the most likely diagnosis, haemoptysis. DD cut offs for ruling out PE were applied: ≤500 ng/mL for high risk and ≤1000 ng/mL for low risk. The outcome measures were the number of positive CTPAs missed and the number of CTPAs avoided. Results: 1527 events were reviewed with 485 (32%) included in our analysis. Detailed findings are shown in figure 1. Two CTPAs (0.4% of scans) were positive for PE, which may not have been performed using the YEARS algorithm (one sub-segmental PE and one PE with atypical history and borderline DD of 990 ng/mL). Application of the YEARS algorithm would have avoided 121 (25%) of all CTPAs. Conclusion: In this audit, application of the YEARS algorithm potentially reduced CTPAs by 25% without significant increased risk.