What is the role of D-dimer (D-dimer test) in evaluating chest pain and shortness of breath in pregnancy?

From the Guidelines

D-dimer testing should not be used to exclude suspected pulmonary embolism (PE) in pregnant women due to its low specificity and potential for false negatives, as evidenced by a retrospective study 1 and supported by guidelines from the American Thoracic Society 1 and the European Society of Cardiology 1.

Key Considerations

• The sensitivity and specificity of D-dimer for suspected PE in pregnancy were calculated to be 73% and 15%, respectively, with a negative likelihood ratio of 1.8, suggesting that a negative D-dimer is inadequate to rule out PE 1.
• D-dimer levels naturally increase throughout pregnancy, making the standard cutoff less specific, especially in later trimesters 1.
• Some studies suggest using trimester-specific cutoffs, but this approach is not universally recommended 1.
• Clinical prediction rules and imaging studies, such as compression ultrasonography or CT pulmonary angiography, should be considered for diagnosing PE in pregnant women 1.

Diagnostic Approach

• A formal diagnostic assessment with validated methods is recommended if PE is suspected during pregnancy or in the post-partum period 1.
• D-dimer measurement and clinical prediction rules can be used to rule out PE, but with caution due to the limitations of D-dimer testing in pregnancy 1.
• Venous compression ultrasound (CUS) can be considered to avoid unnecessary irradiation, especially if symptoms of deep vein thrombosis (DVT) are present 1.
• Perfusion scintigraphy or CT pulmonary angiography (CTPA) with a low-radiation dose protocol can be used to rule out suspected PE in pregnant women, with CTPA considered as the first-line option if the chest X-ray is abnormal 1.

From the Research

Role of D-dimer in Evaluating Chest Pain and Shortness of Breath in Pregnancy

• The D-dimer test is a laboratory assay used to rule out the presence of high D-dimer plasma levels and, by association, venous thromboembolism (VTE) 2.
• In patients with a low or intermediate clinical probability of pulmonary embolism (PE), a D-dimer level of less than 500 ng/mL is associated with a posttest probability of PE less than 1.85%, and PE can be excluded without chest imaging 3.
• The D-dimer test is valuable in ruling out PE in patients who present to the emergency setting with a low pre-test probability (PTP) 2.
• In pregnant patients, the evaluation of chest pain and shortness of breath is complex, and imaging studies are an integral part of the work-up 4.
• Pregnant patients with chest pain or shortness of breath are significantly more likely to undergo a venous duplex, but less likely to undergo a chest X-ray as compared to non-pregnant patients 4.

Diagnostic Approach

• The clinical probability of PE should be the first step for PE workup, using clinical decision rules such as the pulmonary embolism rule-out criteria (PERC) 5.
• If the PERC rule is positive, D-dimer testing can be ordered, and the D-dimer threshold can be adapted for ordering chest imaging using clinical decision rules 5.
• Patients with a high clinical probability of PE should undergo chest imaging without the need for D-dimer testing 3, 5.

Considerations in Pregnancy

• Pregnancy places patients at an increased risk of severe sequelae requiring prompt diagnosis to prevent harm to the mother and fetus 4.
• The American College of Obstetrics and Gynecology (ACOG) Committee Opinion 656 states that, with few exceptions, radiography should not be withheld from pregnant patients 4.
• Further investigation is necessary to verify the association between shortness of breath during pregnancy and subtle cardiac involvement 6.