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Algorithm safely detects pulmonary embolism in pregnant women

A strategy that combines the assessment of clinical probability, D-dimer measurement, compression ultrasonography and CT pulmonary angiography safely and effectively diagnoses pulmonary embolism in pregnant women, according to findings published in Annals of Internal Medicine.

“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,” Marc Righini, MD, Geneva University Hospitals, Switzerland, and colleagues wrote.

Righini and colleagues conducted a multinational study to evaluate a diagnostic algorithm for PE in pregnant women. The researchers enrolled 395 pregnant women with clinically suspected PE in EDs at one of 11 centers in France and Switzerland.

All participants underwent pretest clinical probability assessment and high-sensitivity D-dimer testing. If those test results excluded PE, participants also underwent bilateral lower limb compression ultrasonography, then CT pulmonary angiography if necessary. If all assessments were negative, participants received a ventilation–perfusion scan.

During the 3-month follow-up, the researchers measured the rate of adjudicated venous thromboembolic events.

Overall, 7.1% of participants (n = 28) were diagnosed with PE. Proximal deep venous thrombosis was identified via ultrasound in seven women, CT pulmonary angiography in 19 women and ventilation–perfusion scan in two women.

PE was ruled out in 46 women because of low or intermediate pretest clinical probability and negative D-dimer results, 290 women because of a negative CT pulmonary angiography, 17 women because of normal or low ventilation–perfusion scan results and 14 women for other reasons.

Of the women without a PE diagnosis, 22 received extended anticoagulation, mostly for previous venous thromboembolic disease, during follow-up. At 3 months, there was a 0% rate of symptomatic venous thromboembolic events among participants who did not receive treatment based on negative results on the diagnostic strategy.

“Future research should focus on increasing the yield of noninvasive testing, such as by developing a specific clinical decision rule for suspected PE during pregnancy or using pregnancy-adapted D-dimer cutoff values,” Righini and colleagues concluded.

In an accompanying editorial, Anne Marie Valente, MD, and Katherine E. Economy, MD, both from Brigham and Women’s Hospital, wrote that the study by Righini and colleagues serves as a first step in determining a standard method for diagnosing PE in pregnant women.

“More research is needed to establish pretest probability rules tailored to pregnant women as well as optimal D-dimer levels by trimester,” they wrote. “Through these efforts, we will be able to provide a framework for appropriate standardized diagnostic algorithms in pregnant women with concerning signs and symptoms of PE.” – by Alaina Tedesco

Disclosures: Economy, Righini and Valente reports no relevant financial disclosures. Please see study for all other authors’ relevant financial disclosures.