Thromb Haemostasis
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Multicenter Study
Validity and clinical utility of the simplified Wells rule for assessing clinical probability for the exclusion of pulmonary embolism.
The recently introduced simplified Wells rule for the exclusion of pulmonary embolism (PE) assigns only one point to the seven variables of the original Wells rule. This study was performed to independently validate the simplified Wells rule for the exclusion of PE. We retrospectively calculated the prevalence of PE in the "unlikely" probability categories of the original Wells (cut-off < or =4) and the simplified Wells rule (cut-off < or =1) in 922 consecutive patients with clinically suspected PE from a multicenter cohort study. ⋯ The proportions of patients in whom further tests could safely be withheld based on PE "unlikely" and a normal D-dimer test was 28% (95%CI, 25-31%) using the original and 26% (95%CI, 24-29%) using the simplified Wells rule. In this external retrospective validation study, the simplified Wells rule appeared to be safe and clinically useful, although prospective validation remains necessary. Simplification of the Wells rule may enhance the applicability.