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External validation of the PEGeD diagnostic algorithm for suspected pulmonary embolism in an independent cohort

1Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland, Geneva, Geneve, Switzerland, 2University Hostpial of Angers, Angers, Pays de la Loire, France, 3Innovative Therapies in Haemostasis, INSERM, Université de Paris, Paris, France, Paris, Ile-de-France, France, 4Saint-Luc University Hospital, Bruxelles, Brussels Hoofdstedelijk Gewest, Belgium, 5University of Ottawa, Ottawa, Ontario, Canada, 6Division of Angiology and Hemostasis, Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland, Geneva, Geneve, Switzerland

Abstract Number: OC 31.2

Meeting: ISTH 2022 Congress

Theme: Venous Thromboembolism » VTE Diagnosis

Background: Validated diagnostic algorithms are used to manage patients with clinically suspected pulmonary embolism (PE). The recently published PEGeD study proposed a new diagnostic strategy which appears to safely reduce the use of computed tomography pulmonary angiography (CTPA).

Aims: We aimed to externally validate this diagnostic strategy in an independent cohort.

Methods: We analyzed data from three prospective cohort studies of outpatients with suspected PE. As per the PEGeD algorithm using the Wells score with adapted thresholds, patients were classified as having a low, moderate or high clinical pre-test probability (C-PTP). PE was excluded with a D-dimer < 1000 ng/mL in case of low C-PTP and < 500 ng/mL in case of moderate C-PTP. We assessed the yield and safety of this approach compared to previously validated algorithms.

Results: Among 3302 patients evaluated in our cohort, 1621 (49.0%) patients could have had PE excluded according to the PEGeD diagnostic algorithm, without the need for imaging. Of these patients, 38 (2.3%; 95% CI 1.7 – 3.2) were diagnosed with a symptomatic PE at initial testing or during the 3 month follow-up period. On further analysis, 36 patients out of these 38 patients had a positive age-adjusted D-dimer. The risk of VTE among the 414 patients with a D-dimer below 1000 ng/ml but above the age-adjusted D-dimer cutoff was 36/414 (8.7%; 95 % CI 6.4 – 11.8%).

Conclusion(s): We provide external validation of the PEGeD diagnostic algorithm in an independent cohort. Compared to standard algorithms, the PEGeD diagnostic strategy decreased the number of CTPA examinations required at presentation. However, in our high PE prevalence clinical setting (22%, versus 7% in the PEGeD study) , the risk of false negatives in patients with a negative PEGeD algorithm but with a positive age-adjusted D-dimer deserves caution and further validation studies prior to implementation.

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Study flow chart

To cite this abstract in AMA style:

Robert-Ebadi H, Roy P, Sanchez O, Verschuren F, Le Gal G, Righini M. External validation of the PEGeD diagnostic algorithm for suspected pulmonary embolism in an independent cohort [abstract]. https://abstracts.isth.org/abstract/external-validation-of-the-peged-diagnostic-algorithm-for-suspected-pulmonary-embolism-in-an-independent-cohort/. Accessed August 16, 2022.

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