Diagnosis of Pulmonary Embolism During Pregnancy

Background: Data on the optimal diagnostic management of pregnant women with suspected pulmonary embolism (PE) are limited, and guidelines provide inconsistent recommendations on use of diagnostic tests. Objective: To prospectively validate a diagnostic strategy in pregnant women with suspected PE. Design: Multicenter, multinational, prospective diagnostic management outcome study involving pretest clinical probability assessment, high-sensitivity D-dimer testing, bilateral lower limb compression ultrasonography (CUS), and computed tomography pulmonary angiography (CTPA). (ClinicalTrials.gov: NCT00740454) Setting: 11 centers in France and Switzerland between August 2008 and July 2016. Patients: Pregnant women with clinically suspected PE in emergency departments. Intervention: Pulmonary embolism was excluded in patients with a low or intermediate pretest clinical probability and a negative D-dimer result. All others underwent lower limb CUS and, if results were negative, CTPA. A ventilation–perfusion (V/Q) scan was done if CTPA results were inconclusive. Pulmonary embolism was excluded if results of the diagnostic work-up were negative, and untreated pregnant women had clinical follow-up at 3 months. Measurements: The primary outcome was the rate of adjudicated venous thromboembolic events during the 3-month follow-up. Results: 441 women were assessed for eligibility, and 395 were included in the study. Among these, PE was diagnosed in 28 (7.1%) (proximal deep venous thrombosis found on ultrasonography [n = 7], positive CTPA result [n = 19], and high-probability V/Q scan [n = 2]) and excluded in 367 (clinical probability and negative D-dimer result [n = 46], negative CTPA result [n = 290], normal or low-probability V/Q scan [n = 17], and other reason [n = 14]). Twenty-two women received extended anticoagulation during follow-up, mainly for previous venous thromboembolic disease. The rate of symptomatic venous thromboembolic events was 0.0% (95% CI, 0.0% to 1.0%) among untreated women after exclusion of PE on the basis of negative results on the diagnostic work-up. Limitation: There were several protocol deviations, reflecting the difficulty of performing studies in pregnant women with suspected PE. Conclusion: A diagnostic strategy based on assessment of clinical probability, D-dimer measurement, CUS, and CTPA can safely rule out PE in pregnant women. Primary Funding Source: Swiss National Foundation for Scientific Research, Groupe d'Etude de la Thrombose de Bretagne Occidentale, and International Society on Thrombosis and Haemostasis.