In a prospective study involving pregnant women with suspected pulmonary embolism (PE), the authors used clinical based criteria from the established YEARS algorithm (clinical signs of deep-vein thrombosis, hemoptysis, and pulmonary embolism as the most likely diagnosis). They additionally measured the d-dimer level. They ruled out PE if none of the three criteria were met and the d-dimer level was less than 1000 ng/per milliliter or if one or more of the three criteria were met and the d-dimer level was less than 500 ng per milliliter. For all the patients in whom PE had not been ruled out underwent CT pulmonary angiography (CTPA). The primary outcome was the incidence of venous thromboembolism at 3 months. The secondary outcome was the proportion of patients in whom CTPA was not indicated to safely rule out PE. Using the above criteria CTPA was avoided in 65% of patients who began the study in the first trimester and in 32% who began the study in the third trimester.
Comment
This prospective study provides evidence that a combined assessment of clinical based variables plus d-dimer levels could safely exclude PE in pregnant women. The above beneficial effect is critical since it eliminates the radiation exposure.