OC 31.2 - External validation of the PEGeD diagnostic algorithm for suspected pulmonary embolism in an independent cohort

Monday, July 11, 2022

11:00 AM – 11:15 AM

Location: ExCel Center, S11A

Presentation Format: In-Person

Co-Author(s)

Helia Robert-Ebadi, MD

MD
Division of Angiology and Hemostasis, Geneva University Hospital and Faculty of Medicine, Geneva, Switzerland
Geneva, Geneve, Switzerland
PR

Pierre-Marie Roy

MD, PhD
Service des urgences, Centre Hospitalo-Universitaire d’Angers, Institut MITOVASC, EA 3860, Université d'Angers, Angers, FCRIN INNOVTE, France.
Angers, Pays de la Loire, France
OS

Olivier Sanchez

MD, PhD
Georges Pompidou European Hospital, Paris, France
Paris, Ile-de-France, France
FV

Franck Verschuren

MD, PhD
Université Catholique de Louvain, IREC Institute, Emergency Department, Saint-Luc University Hospital, Brussels, Belgium
Brussels, Brussels Hoofdstedelijk Gewest, Belgium
GL

Grégoire Le Gal

Professor
University of Ottawa
Ottawa, Ontario, Canada

Presenting Author(s)

Marc Righini, MD

MD
Division of Angiology and Hemostasis, Geneva University Hospital and Faculty of Medicine, Geneva, Switzerland
Geneve, Geneve, Switzerland

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.