Algorithm Rules Out Pulmonary Embolism in Pregnancy

By Kelly Young

Edited by David G. Fairchild, MD, MPH, and Jaye Elizabeth Hefner, MD

A new algorithm may help safely rule out pulmonary embolism (PE) in pregnant women, according to an Annals of Internal Medicine study.

Nearly 400 pregnant women with suspected PE were given pretest assessments with the revised Geneva score. The algorithm included the following:

• Women with a high revised Geneva score (indicating a high probability of PE) underwent bilateral leg compression ultrasound.

• Those with a low or intermediate Geneva score underwent D-dimer testing.

• If the D-dimer test was positive, they underwent leg ultrasound. If it was negative, PE was ruled out.

• Positive ultrasounds meant a PE diagnosis. Women with negative ultrasounds underwent computed tomography pulmonary angiography (CTPA).

• Positive CTPA results indicated PE, negative results ruled it out, and inconclusive results meant women were to undergo ventilation-perfusion (V/Q) lung scanning.

The algorithm diagnosed PE in 7% of the women. At 3 months, the rate of the primary outcome — adjudicated venous thromboembolism events in women with negative PE results who didn't receive anticoagulation — was 0%.

Editorialists conclude that the study "is an initial step in establishing a standardized approach to diagnosing PE in pregnant women."