September 3, 2018

EM Journal Update: Safety of Using Wells’ Clinical Model With D-Dimer To Manage Patients In The ED With Suspected Pulmonary Embolism

Background: In the US, pulmonary embolism (PE) kills 100,000 people each year and over 360,000 new cases of PE are diagnosed each year (Horlander 2003). Currently, the gold standard for diagnosing PE is the computed tomographic pulmonary angiography (CTPA). Patients with PE present with varying symptoms, from anxiety and tachycardia, to shortness of breath and syncope. Thus, it is difficult to exclude this life-threatening diagnosis and thus far there is no validated method to exclude PE. Prior work from this group derived and validated Wells’ criteria for calculating clinical probability of PE, and using it to determine which patients should get serial ultrasonography, venography, or angiography after an equivocal ventilation perfusion (VQ) scan (Wells 1998). Now, this group examines how the D-dimer assay, together with Wells’ clinical model can help manage PE patients.

March 19, 2018

Background: Pulmonary embolism is the leading cause of death in pregnancy and the puerperium - accounting for nearly 20% of maternal deaths in the United States - making rapid and accurate diagnosis critically important for emergency physicians, OB/GYNs, and all who take care of these women on a regular basis. Unfortunately, typical diagnostic pathways and approaches may not apply in pregnancy, and are made more complicated by the frequency of concerning and suggestive signs and symptoms in this population, particularly dyspnea (a common symptom in pregnancy related to an increase in progesterone levels) and tachycardia (as resting heart rate is typically expected to increase by up to 25% in normal pregnancy).

April 28, 2014

D-dimer testing is sensitive for thrombus formation, and in patients who are not high risk, this test is used to rule-out venous thromboembolism. D-dimer has been shown to increase with age, which can cause a lower specificity (i.e. more false positive tests) in older patients.  Specificity can range from 49 - 67% in patients ≤ 50 years of age, but in older patients (i.e. ≥ 80 years of age) the specificity is quoted as 0 - 18%. The result of this is, older patients often have more diagnostic imaging, but a higher cut-off may lead to increased false negative cases (i.e. missed VTE) and make this strategy less safe. So could age adjusted d-dimer testing increase specificity without affecting sensitivity?