Multicentric case-control study that is aims at:

• evaluating the prevalence of pulmonary embolism among a large population of consecutive patients admitted for COVID-19 pneumonia into two large university hospitals in Paris, France: Groupe Hospitalier Paris Saint-Joseph (GHPSJ) and Hôpital Européen Georges Pompidou (HEGP)
• and identifying the characteristics associated with pulmonary embolism by using a nested case control study design within the patients who underwent either unenhanced computed tomograpghy (CT) or CT pulmonary angiogram (CTPA) evaluation.

In December 2019, China reported the first cluster of severe acute respiratory syndrome due to a new coronavirus (SARS-CoV-2). The disease rapidly spread into a global pandemic of public health emergency worldwide leading to more than 330.000 deaths (data from May 25th, 2020). We have, to date, no demonstration on the efficacy of any drug to cure or prevent severe evolution of the disease (COVID-19). The primary target of SARS-CoV-2 is the lung with frequent occurrence of acute respiratory distress syndrome (ARDS) justifying supportive care, including invasive mechanical ventilation (IMV). The characteristics of ARDS in COVID-19 patients appeared atypical due to the dissociation between initial well-conserved lung compliance and severe hypoxemia, attributed to pulmonary vasoregulation disruption and local thrombogenesis. Strikingly high D-dimers levels, caused by both inflammation storm and coagulation activation, have been early reported in COVID-19 patients and have been associated with increased mortality. A single observational study suggests that anticoagulation is associated with a decreased mortality in severe COVID-19 patients. These reports have led to several therapeutic propositions in terms of anticoagulant therapy from worldwide scientific societies (Khider et al JMV 2020). Publications recently reported thrombotic complications in series of severe COVID-19 patients admitted in ICU, but the frequency of pulmonary embolism (PE) in larger cohort of COVID-19 patients of any severity remains uncertain.

This cohort enrolled patients in whom PE is proven by CTPA and compared them into two subgroups of controls matched for age and sex in whom PE was either excluded or non suspected:

1. COVID-19 patients with a negative CTPA and
2. COVID-19 patients in whom only an unhenced CT was performed.

Inclusion Criteria:

• patients >18 years,
• admitted for acute COVID-19 pneumonia and have recieved a chest CT scan during hospitalization,
• COVID-19 diagnosis confirmed by a positive result of a RT-PCR,
• CT findings of COVID-19 pneumonia.

Exclusion Criteria:

• Respiratory distress syndrome explained by other cause
• Patients who refuse to participate to the study.

Patients aged over 18 years, hospitalized for respiratory pathology, associated with the COVID-19; confirmed by either a RT-PCR test or a CT scan.