YEARS Algorithm Versus Wells' Score: Predictive Accuracies in Pulmonary Embolism Based on the Gold Standard CT Pulmonary Angiography*

Objectives: This study retrospectively applied Wells' score and YEARS algorithm to the same sample of patients to evaluate the predictive performance of each when compared with the gold standard CT pulmonary angiography. Design: Retrospective analytical study. Setting: A tertiary University Hospital in Ireland. Patients: Data from 794 patients who underwent CT pulmonary angiography to rule out pulmonary embolism. Interventions: Patients were analyzed using retrospective application of both Wells' score and YEARS algorithm. Sensitivity, specificity, and diagnostic odds ratio were calculated and compared. Measurements and Main Results: Of 794 scans, 78 (9.8%) were positive for pulmonary embolism. The YEARS algorithm was more sensitive than the Wells' score (97.44% vs 74.36%) but was less specific (13.97% vs 33.94%). Furthermore, the diagnostic odds ratio of YEARS was higher than Wells' score (6.27 vs 1.48). YEARS provides better negative predictive value (98% vs 92.4%), and both scores have poor positive predictive value (10.9%). Conclusions: Both scores successfully exclude pulmonary embolism, although YEARS has a better negative predictive value. Both exhibit poor positive predictive value.