key: cord-0925726-3nmjuyii
authors: Leonard-Lorant, Ian; Delabranche, Xavier; Severac, François; Helms, Julie; Pauzet, Coralie; Collange, Olivier; Schneider, Françis; Labani, Aissam; Bilbault, Pascal; Moliere, Sébastien; Leyendecker, Pierre; Roy, Catherine; Ohana, Mickaël
title: Acute Pulmonary Embolism in COVID-19 Patients on CT Angiography and Relationship to D-Dimer Levels
date: 2020-04-23
journal: Radiology
DOI: 10.1148/radiol.2020201561
sha: 17a37303835190ddbe8d58c911bb9134a5cef7d1
doc_id: 925726
cord_uid: 3nmjuyii

nan

Reports of acute pulmonary embolism associated with COVID-19 have emerged in the literature. For example, Chen et al. described 25 pulmonary CT angiograms examinations from 1008 COVID-19 patients; 10 were positive for pulmonary embolism mostly as segmental or sub-segmental APE [1] . In addition, D-dimer levels have been reported as elevated in patients with COVID-19 [2; 3] with the suggestion of an independent association between the severity of the disease and the level of D-dimer [4] . The purpose of this report is to describe the rate of pulmonary embolus in patients classified as COVID-19 infection and who underwent chest CT at a tertiary referral centre.

The local ethics committee of Strasbourg University Hospital approved this retrospective study and 

Fibrinogen and D-dimer levels were recorded for all patients who had pulmonary CT angiography. All patients with pulmonary CT angiography were evaluated for reverse transcriptase polymerase chain reaction (RT-PCR) results for SARS-CoV-2. All initial samples were obtained by nasopharyngeal swab; some patients had second or third sampling using sputum or bronchoalveolar lavage. Any positive result was classified as confirmed COVID-19 infection. When RT-PCR was negative, chest CT was reviewed by a senior chest radiologist (MO, with 14 years of experience) to look for characteristic COVID-19 lung parenchyma lesions. When CT images were considered typical (i.e. extensive bilateral and peripheral ground glass opacities and/or alveolar consolidation) and clinical data were compatible, the patient was also adjudicated as having COVID-19 [4; 5] . Table. I n P r e s s Patients with COVID-19 infection and pulmonary embolus had higher D-dimer levels than those without pulmonary embolus (median, IQR 6110±4905 versus 1920±3674 µg/L, respectively, p<.001), were more likely to be in the intensive care unit (24/32 (75%) versus 24/74 (32%), p<.001) and were treated more often with low weight molecular heparin before CT angiography (25/32 (78%) versus 17/74 (23%), p<.001) (Table) . In these patients with COVID-19 infection, D-dimer greater than 2660 µg/L had a sensitivity of 32/32 (100%, 95%CI 88-100) and a specificity of 49/74 (67%, 95% CI 52-79) for pulmonary embolism on CT angiography. See Figure 2 for an example patient.

Our study demonstrated that of 106 pulmonary CT angiograms performed for COVID-19 patients over a one-month period in a tertiary care centre; 32/106 (30%) of patients had acute pulmonary embolus.

This rate of pulmonary embolus is higher than usually encountered in critically ill patients without COVID-19 infection (1.3%, [6] ) or in emergency department patients (3 to 10% [7] ). In our patient population, a D-dimer threshold of 2660 µg/L detected all patients with pulmonary embolus on chest CT. This threshold of 2660 µg/L is higher than previously reported median level of 2400 [8] and 900 [2] and is higher than cut-off values used to exclude pulmonary embolus in non-ICU patients [9] . High values of d-dimer could be related to a higher activation of blood coagulation in COVID-19 patients secondary to a systemic inflammatory response syndrome -or as a direct consequence of the SARS-CoV-2 itself. Although a single center retrospective report, our results of the potential for pulmonary

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