key: cord-258895-bfosmipc
authors: Jalaber, Carole; Revel, Marie-Pierre; Chassagnon, Guillaume; Bajeux, Emma; Lapotre, Thibaut; Croisille, Pierre; Lederlin, Mathieu
title: Role of upfront CT pulmonary angiography at admission in COVID-19 patients
date: 2020-08-25
journal: Thromb Res
DOI: 10.1016/j.thromres.2020.08.037
sha: 
doc_id: 258895
cord_uid: bfosmipc

• Current guidelines recommend the use of unenhanced chest CT as first-line imaging in patients suspected of having COVID-19 pneumonia. • In unselected COVID-19 patients, the prevalence of acute PE at baseline is no different from that observed in COVID-19 negative patients. • There is no clear evidence that there is a benefit to routinely perform CT pulmonary angiography as first-line imaging modality in patients suspected of COVID-19 pneumonia.

Current guidelines recommend the use of unenhanced chest computed tomography (CT) as first-line imaging in patients suspected of having COVID-19 pneumonia, in order to assess the extent of lung damage (1, 2) . Although most patients have a favorable disease course, some of them develop secondary disease worsening due to an excessive systemic inflammatory response, evidenced by high serum levels of biomarkers such as IL-6, which promotes an hypercoagulability state leading to thrombotic complications (3, 4) . A D-dimer level greater than 1000 μg/L has been clearly identified as a risk factor for poor outcome (5) .

However, little is known about the exact prevalence of thromboembolism in patients. Recent studies (6, 7, 8) have reported a high cumulative incidence of acute pulmonary embolism (PE), ranging from 23% to 30%, but these reports mainly concerned severe patients admitted in ICU. To date, the prevalence of acute PE at baseline presentation of unselected COVID-19 patients remains unknown, as is the benefit of a systematic CT pulmonary angiography (CTPA) at initial screening.

The objective of this study was to evaluate the prevalence of PE when systematically performing CT pulmonary angiography (CTPA) as first-line imaging modality in patients with COVID-19 suspicion.

J o u r n a l P r e -p r o o f

This retrospective study was approved by the local ethics committee of xxxx (Blinded for review), which waived the need for patient consent.

From March 26 th , 2020, following the reports of frequent PE in COVID-19 patients (9, 10) , it was decided to systematically perform CTPA as first-line imaging modality in patients suspected of COVID-19 at xxxx (Blinded for review) University Hospital, unless there were contraindications to contrast medium administration. We retrospectively included all consecutive patients suspected of COVID-19 presenting at the emergency department who had undergone systematic CTPA between March 26 th and April 17 th , 2020.

All patients had reverse transcriptase -polymerase chain reaction (RT-PCR) nasopharyngeal swab test for SARS-Cov-2 on the same day as the CTPA. In case of first negative RT-PCR result and high clinical suspicion, swab test was repeated.

Demographics, clinical and biological data as well as patients' outcomes were collected from medical charts. The evaluated clinical parameters included age, sex, comorbidities (obesity, type 2 diabetes, respiratory or cardiovascular disease, hypertension), delay from symptoms onset as well as for oxygen needs, ICU admission or mechanical ventilation. Biological data included D-dimer, C-reactive protein, lactate dehydrogenase levels and lymphocyte count.

Patients with a single negative RT-PCR result, who had typical CT features of COVID-19 pneumonia in addition to suggestive symptoms and laboratory results were considered as COVID-19 positive.

Cases of contrast medium extravasation after intravenous administration or of serum creatinine increase in the following days after CTPA were reported. 

Statistical analysis was performed using the statistical software package "R" (version 3.2.1, R Foundation, Vienna, Austria). Demographics, clinical and biological between patients with and without PE were compared using t test and Fisher exact test. Disease extent was compared using a Cochran-Armitage trend test. P values less than 0.5 were considered as statistically significant. Figure 1 shows the flowchart of the study. Patient characteristics are presented in Table 1 . Regarding complications of contrast administration, 3 of the 199 patients who underwent CTPA presented contrast extravasation and 3 elderly patients (mean age 85.3 ± 4.7), of which 2 had type 2 diabetes, presented subsequent increase of the serum creatinine above 614 ± 100 µmol/L, resulting in a 3.0% (6/199) complication rate following contrast medium administration.

Since the outbreak of the COVID-19 epidemic, the impact of unenhanced chest CT has been widely reported and is no longer discussed (11,12). Given the high risk of pulmonary embolism in the COVID-19 pneumonia, first-line CTPA is an option that deserves to be considered. To the best of our knowledge, this is the first study reporting PE prevalence in unselected COVID-19 patients at initial presentation. Previous studies on PE mainly concerned severe COVID-19 patients admitted to ICU. Our study shows that the prevalence of acute PE at initial presentation is low, below 6%, and not different from that observed for COVID-19 negative patients.

Dyspnea and desaturation are common symptoms of both COVID-19 and pulmonary embolism, and clinical triage is difficult. Furthermore, the Wells or Geneva pre-test probability scores usually used for outpatients with PE suspicion have not been validated for COVID-19

patients. Most patients with SARS-Cov2 infection had elevated D-dimers, but a value above 5000 µg/L was only observed in patients with PE. Even if it is not possible to draw a definitive conclusion on a limited series, our data suggest considering contrast administration at initial presentation of patients with COVID-19 suspicion who have marked elevation of D-dimers.

There was a 7-day median interval between symptoms onset and CTPA in our study which is shorter than that reported (12 to 14 days) in studies reporting 23% to 30% cumulative incidence of PE in COVID-19 patients (6, 8) . These results support the hypothesis of a This study has several limitations, including its retrospective nature, the small number of events and the lack of follow-up especially regarding late thromboembolic events.

Nonetheless, we believe that the present study improves the current knowledge on COVID-19 disease, by reporting a low PE prevalence at initial presentation.

To conclude, this study does not provide clear evidence that there is a benefit to routinely perform CTPA as first-line imaging modality in patients suspected of COVID-19 pneumonia. 

The Role of Chest Imaging in Patient Management during the COVID-19 Pandemic : A Multinational Consensus Statement from the Fleischner Society

COVID-19 patients and the radiology department -advice from the European Society of Radiology (ESR) and the European Society of Thoracic Imaging (ESTI)

Thromboinflammation and the hypercoagulability of COVID-19

Incidence of thrombotic complications in critically ill ICU patients with COVID-19

Abnormal coagulation parameters are associated with poor prognosis in patients with novel coronavirus pneumonia

Acute pulmonary embolism in COVID-19 patients on CT angiography and relationship to D-dimer levels

Pulmonary embolism in patients with Covid-19 pneumonia

Acute Pulmonary Embolism Associated with COVID-19 Pneumonia Detected by Pulmonary CT Angiography

Acute pulmonary embolism and COVID-19 pneumonia : a random association?

Pulmonary embolism in patients with COVID-19: Time to change the paradigm of computed tomography