Strategies to safely rule out pulmonary embolism in COVID-19 outpatients: a multicenter retrospective study.

Chassagnon, Guillaume El Hajjam, Mostafa Boussouar, Samia Revel, Marie-Pierre Khoury, Ralph Ghaye, Benoît [UCL] Bommart, Sebastien Lederlin, Mathieu Tran Ba, Stephane De Margerie-Mellon, Constance Fournier, Laure Cassagnes, Lucie Ohana, Mickael Jalaber, Carole Dournes, Gael Cazeneuve, Nicolas Ferretti, Gilbert Talabard, Pauline Donciu, Victoria Canniff, Emma Debray, Marie-Pierre Crutzen, Bernard [UCL] Charriot, Jeremy Rabeau, Valentin Khafagy, Philippe Chocron, Richard Leonard Lorant, Ian Metairy, Loic Ruez-Lantuejoul, Lea Beaune, Sébastien Hausfater, Pierre Truchot, Jennifer Khalil, Antoine Penaloza-Baeza, Andrea [UCL] Affole, Thibaut Brillet, Pierre-Yves Roy, Catherine Pucheux, Julien Zbili, Jordan Sanchez, Olivier Porcher, Raphael on the behalf of the French Society of Thoracic Imaging et al.[show all]

OBJECTIVES: The objective was to define a safe strategy to exclude pulmonary embolism (PE) in COVID-19 outpatients, without performing CT pulmonary angiogram (CTPA). METHODS: COVID-19 outpatients from 15 university hospitals who underwent a CTPA were retrospectively evaluated. D-Dimers, variables of the revised Geneva and Wells scores, as well as laboratory findings and clinical characteristics related to COVID-19 pneumonia, were collected. CTPA reports were reviewed for the presence of PE and the extent of COVID-19 disease. PE rule-out strategies were based solely on D-Dimer tests using different thresholds, the revised Geneva and Wells scores, and a COVID-19 PE prediction model built on our dataset were compared. The area under the receiver operating characteristics curve (AUC), failure rate, and efficiency were calculated. RESULTS: In total, 1369 patients were included of whom 124 were PE positive (9.1%). Failure rate and efficiency of D-Dimer > 500 µg/l were 0.9% (95%CI, 0.2-4.8%) and 10.1% (8.5-11.9%), respectively, increasing to 1.0% (0.2-5.3%) and 16.4% (14.4-18.7%), respectively, for an age-adjusted D-Dimer level. D-dimer > 1000 µg/l led to an unacceptable failure rate to 8.1% (4.4-14.5%). The best performances of the revised Geneva and Wells scores were obtained using the age-adjusted D-Dimer level. They had the same failure rate of 1.0% (0.2-5.3%) for efficiency of 16.8% (14.7-19.1%), and 16.9% (14.8-19.2%) respectively. The developed COVID-19 PE prediction model had an AUC of 0.609 (0.594-0.623) with an efficiency of 20.5% (18.4-22.8%) when its failure was set to 0.8%. CONCLUSIONS: The strategy to safely exclude PE in COVID-19 outpatients should not differ from that used in non-COVID-19 patients. The added value of the COVID-19 PE prediction model is minor. KEY POINTS: • D-dimer level remains the most important predictor of pulmonary embolism in COVID-19 patients. • The AUCs of the revised Geneva and Wells scores using an age-adjusted D-dimer threshold were 0.587 (95%CI, 0.572 to 0.603) and 0.588 (95%CI, 0.572 to 0.603). • The AUC of COVID-19-specific strategy to rule out pulmonary embolism ranged from 0.513 (95%CI: 0.503 to 0.522) to 0.609 (95%CI: 0.594 to 0.623).