BACKGROUND AND PURPOSE:

• Pulmonary embolism (PE) results in 1 death per 100,000 deliveries and is associated with maternal mortality
• Women with suspected PE undergo CT pulmonary angiography or ventilation–perfusion scan
  • Medically warranted but does result in radiation exposure
• Van der Pol et al. (NEJM, 2019) investigated whether a pregnancy-adapted algorithm including d-dimer test could be used as an alternative to CT scan

METHODS:

• Prospective, multicenter study
• Participants
  • Pregnant women with suspected pulmonary embolism
  • Worsening chest pain or dyspnea +/- hemoptysis or tachycardia
  • Extension of YEARS study (started in 2013) to include exclusively pregnant women
• Assessments
  • Assessed three criteria from the YEARS algorithm
    • Clinical signs of DVT
    • Hemoptysis
    • Pulmonary embolism considered likely diagnosis based on history and physical
  • Measured d-dimer level
• Pulmonary embolism was ruled out and treatment withheld if either
  • None of the three criteria were met and d-dimer level <1000 ng/mL
  • ≥1 of the 3 assessment criteria met and d-dimer level was <500 ng per milliliter
• Pregnancy adaptation: If DVT symptoms present, compression ultrasound performed
  • Positive (clot was present): PE diagnosis considered established and continued to treatment with no other diagnostic imaging
  • Negative (normal ultrasound): Continue to algorithm
• Primary outcome
  • Incidence of venous thromboembolism (VTE) at 3 months confirmed objectively in rule out group
• Secondary outcome
  • Proportion of patients in whom CT pulmonary angiography was not indicated to safely rule out pulmonary embolism, compared to hypothetical cohort where all patients would have had CT pulmonary angiography or ventilation–perfusion scanning

RESULTS:

• 498 women included
• PE diagnosis at baseline: 4.0% at baseline
• VTE diagnosis during follow-up
  • 0.21% (n=1) with popliteal deep-vein thrombosis (95% CI, 0.04 to 1.2)
  • No PE
• CT pulmonary angiography
  • Not indicated (avoided): 39% (95% CI, 35 to 44)
• Efficiency of algorithm highest during the first trimester of pregnancy and lowest during the third trimester
  • 1st trimester: 65% avoided
  • 3rd trimester: 32% avoided

CONCLUSION:

• The pregnancy-adapted YEARS diagnostic algorithm can be used to rule out pulmonary embolism throughout pregnancy
• CT approach can be avoided in 32-65% of patients

Learn More – Primary Sources:

Pregnancy-Adapted YEARS Algorithm for Diagnosis of Suspected Pulmonary Embolism

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