Author: Michael Hunt, M.D. Educational Pearls In the recent YEARS study, investigators checked every patient with suspicion for PE with a D-dimer, using a modified Wells score for risk stratification. The goal of the study was to show that CT scan usage could safely reduced using this screening method. The Wells Criteria measures they used to stratify risk were: PE mostly likely dx, hemoptysis, and evidence of DVT. If the d-dimer was 1, but the patient had none of the Wells criteria, the patient did not get a CT. If the patient had any of the criteria, but the d-dimer was only 0.5, the patient did not get a CT scan. The investigators reduced  CT usage by 14% using the new criteria, with no significant increase in morbidity and mortality. References: van der Hulle et al. Simplified diagnostic management of suspected pulmonary embolism (the YEARS study): a prospective, multicentre, cohort study. The Lancet. 2017