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Clinical Question
Can a clinical prediction rule safely help pregnant women avoid unnecessary imaging for the evaluation of suspected pulmonary embolism?
Bottom line
The YEARS algorithm adapted for pregnancy safely identifies approximately 40% of women who are clinically suspected of having pulmonary embolism (PE) as not requiring computed tomographic (CT) imaging. 1b
Reference
Study design: Decision rule (validation)
Funding: Government
Setting: Inpatient (any location)
Synopsis
Several clinical prediction rules have been developed to aid in the diagnosis of PE, such as the Wells, Geneva, and Pisa scores. However, all of them carry a caution against use in pregnant women. The YEARS algorithm is one such prediction rule, and was adapted by the authors as follows for use in pregnant women: (1) Count the number of YEARS criteria (clinical signs of deep vein thrombosis [DVT], hemoptysis, or PE felt to be most likely diagnosis) and order a D-dimer test. (2) If clinical signs of DVT, perform compression ultrasonography, and if the result is abnormal, begin anticoagulation. (3) If the ultrasound result is normal, count YEARS criteria. (4) If 1 to 3 YEARS and D-dimer >= 500 ng/mL OR if 0 YEARS criteria and D-dimer > 1000 ng/mL, perform CT pulmonary angiography and treat accordingly. (5) If 1 to 3 YEARS and D-dimer < 500 ng/mL OR if no YEARS and D-dimer < 1000 ng/mL, consider PE ruled out. The algorithm performed well in the prospective validation study, which enrolled 498 pregnant women with clinically suspected PE and a mean age of 30 years and a median duration of pregnancy of 25 weeks. Among the 299 women with 1 to 3 YEARS criteria and D-dimer >= 500 ng/mL OR if 0 YEARS criteria and D-dimer > 1000 ng/mL (the high-risk group) for whom CT angiography was recommended,16 had a PE and 283 had an uneventful follow-up. Among the 195 women with 1 to 3 YEARS criteria and D-dimer < 500 ng/mL OR no YEARS and D-dimer < 1000 ng/mL (the low-risk group), one had a DVT diagnosed during follow-up but none had a PE diagnosed. CT pulmonary angiography was avoided in 39% of patients (65% in the first trimester, 32% in the third trimester) while maintaining safety standards.
Reviewer
Mark H. Ebell, MD, MS
Professor
University of Georgia
Athens, GA