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Strategies to safely rule out pulmonary embolism in COVID-19 outpatients: a multicenter retrospective study
Guillaume Chassagnon1, Mostafa El Hajjam2, Samia Boussouar3
1Radiology Department, Hôpital Cochin, AP-HP, Université Paris Cité, 27 Rue du Faubourg Saint-Jacques, 75014, Paris, France. guillaume.chassagnon@aphp.fr.
Insights
A safe strategy to rule out pulmonary embolism (PE) in COVID-19 outpatients does not differ from non-COVID-19 patients, with D-dimer levels being the key predictor. A COVID-19 specific prediction model showed only minor added value.
Area of Science:
- Pulmonary Medicine
- Infectious Diseases
- Diagnostic Imaging
Background:
- Pulmonary embolism (PE) is a concern in COVID-19 patients.
- CT pulmonary angiography (CTPA) is often used for diagnosis but carries risks.
- Developing a safe, non-invasive strategy to exclude PE in COVID-19 outpatients is crucial.
Purpose of the Study:
- To define a safe strategy for excluding PE in COVID-19 outpatients without CTPA.
- To compare the efficacy of D-dimer testing, clinical scores, and a novel prediction model.
Main Methods:
- Retrospective evaluation of 1369 COVID-19 outpatients who underwent CTPA.
- Collected data included D-dimer levels, revised Geneva and Wells scores, and clinical characteristics.
- Compared PE rule-out strategies using D-dimer thresholds, clinical scores, and a COVID-19 PE prediction model.
Main Results:
- PE was present in 9.1% of patients.
- Age-adjusted D-dimer levels showed a low failure rate (1.0%) and improved efficiency.
- The COVID-19 PE prediction model had a minor added value compared to standard scores and D-dimer.
Conclusions:
- The strategy to exclude PE in COVID-19 outpatients is similar to non-COVID-19 patients.
- D-dimer levels remain the most significant predictor for PE in this population.
- A COVID-19-specific prediction model offers limited additional benefit.
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).
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