Simplified Diagnosis of Acute PE: The YEARS Study
What is the validity of a simple diagnostic algorithm (the YEARS clinical decision rule) for diagnosis of acute pulmonary embolism (PE)?
The authors performed a prospective, multicenter, cohort study in 12 hospitals with consecutive patients suspected of presenting with acute PE between October 5, 2013 and July 9, 2015. Patients were managed based on the YEARS clinical decision rule, which involves clinical signs of deep vein thrombosis, hemoptysis, if PE is the most likely diagnosis, and the D-dimer concentration. Acute PE was thought to be “ruled out” if no clinical items were present and the D-dimer concentration was <1000 ng/ml or in patients with 1+ clinical items, but a D-dimer concentration of <500 ng/ml. All other patients underwent computed tomography pulmonary angiogram (CTPA). The primary outcome was the number of independently adjudicated venous thromboembolism (VTE) events within 3 months.
A total of 3,465 patients were enrolled in the study, of whom 456 (13%) were diagnosed with PE at baseline. Of the remaining 2,946 (85%) patients who were “ruled out” for acute PE at baseline and left untreated, 19 patients were diagnosed with symptomatic VTE within 3 months (0.61%, 95% confidence interval, 0.36-0.96). CTPA was not indicated in 1,651 (48%) of patients based on the YEARS algorithm as compared to 1,174 (34%) of patients based on a Wells’ rule and fixed D-dimer threshold of 500 ng/ml.
The authors concluded that the use of the YEARS diagnostic algorithm can safely exclude patients with PE and may decrease the use of CTPA studies as compared to the Wells’ criteria and fixed D-dimer threshold.
Testing for suspected PE is a common occurrence in emergency departments. However, many patients with low probability Wells’ scores and positive D-dimer tests or intermediate-high probability Wells’ scores undergo CTPA testing, perhaps unnecessarily. The YEARS diagnostic algorithm applies simple clinical criteria to a two-tiered D-dimer threshold to further reduce the use of CTPA testing while still having very high negative predictive ability for acute PE. Since the inception of this study, an age-adjusted D-dimer threshold (age x 10 for age 50+) has been introduced and may further reduce the use of CTPA testing in low-risk patients (JAMA 2014;311:1117-24). Clinicians should maintain a high degree of suspicion for possible acute PE, but use a validated diagnostic approach (e.g., Wells’ or YEARS) along with a D-dimer (perhaps with age-adjusted threshold) to appropriately select patients for CTPA testing.
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