Objective Recent studies suggest that combinations of clinical probability assessment (the YEARS algorithm or Geneva score) and D-dimer can safely rule out suspected pulmonary embolism (PE) in pregnant women. We performed a secondary analysis of the DiPEP (Diagnosis of Pulmonary Embolism in Pregnancy) study data to determine the diagnostic accuracy of these strategies.
Methods The DiPEP study prospectively recruited and collected data and blood samples from pregnant/postpartum women with suspected PE across 11 hospitals and retrospectively collected data from pregnant/postpartum women with diagnosed PE across all UK hospitals (15 February 2015 to 31 August 2016). We selected prospectively recruited pregnant women who had definitive diagnostic imaging for this analysis. We used clinical data and D-dimer results to determine whether the rule out strategies would recommend further investigation. Two independent adjudicators used data from imaging reports, treatments and adverse events up to 30 days to determine the reference standard.
Results PEs were diagnosed in 12/219 (5.5%) women. The YEARS/D-dimer strategy would have ruled out PE in 96/219 (43.8%) but this would have included 5 of the 12 with PEs. Sensitivity for PE was 58.3% (95% CI 28.6% to 83.5%) and specificity 44.0% (37.1% to 51.0%). The Geneva/D-dimer strategy would have ruled out PE in 46/219 (21.0%) but this would have included three of the 12 with PE. Sensitivity was 75.0% (95% CI 42.8% to 93.3%) and specificity 20.8% (95% CI 15.6% to 27.1%). Administration of anticoagulants prior to blood sampling may have reduced D-dimer sensitivity for small PE.
Conclusion Strategies using clinical probability and D-dimer have limited diagnostic accuracy and do not accurately rule out all PE in pregnancy. It is uncertain whether PE missed by these strategies lead to clinically important consequences.
- pulmonary embolism
- thrombo-embolic disease, diagnosis
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Contributors SG was the chief investigator for the DiPEP study. This analysis was planned by SG, CN-P, BH and GF. SG undertook the statistical analysis. SG, CN-P, BH and GF contributed to interpretation of the data. SG wrote the initial draft of the paper. SG, CN-P, BH and GF contributed to redrafting and approved the final draft of the paper. SG is guarantor for the paper.
Funding The DiPEP study was funded by the UK National Institute for Health Research Health Technology Assessment (HTA) programme (project reference 13/21/01). The funding proposal was submitted in response to a commissioning call that involved patient and public assessment for priority, and was subject to external peer review for quality.
Competing interests The study was funded by the NIHR Health Technology Assessment Programme. SG is deputy director of the HTA Programme and chairs the HTA Commissioning Committee.
Patient and public involvement Patients and/or the public were involved in the design, or conduct, or reporting, or dissemination plans of this research. Refer to the Methods section for further details.
Patient consent for publication Not required.
Ethics approval The DiPEP study was approved by the London Brent Research Ethics Committee (reference 14/LO/1695) on 10 October 2014.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available on reasonable request from the authors. The data are deidentified participant data, available from the lead author (ORCID 0000-0003-0803-8444), for up to 5 years, under condition that reuse for publication is based on a prospectively registered protocol with a planned analysis.
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