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Pulmonary Embolism in COVID-19 Patients: Awareness of an Increased Prevalence

Our take —

COVID-19 patients in the ICU may be at increased risk for pulmonary embolism, which has the potential to worsen individual prognosis if not identified and managed appropriately. Despite the study’s small sample and potential for selection bias due to differences in CTPA screening, the absolute difference in rates of pulmonary embolism between COVID-19 patients and the two control groups warrants further attention and replication in longitudinal studies.

Study design

Case Series

Study population and setting

This case-series included 107 patients with confirmed COVID-19, who were consecutively admitted to the ICU for pneumonia at Lille University Hospital (the tertiary care center for the North-of-France region) between February 27 and March 31, 2020. The cumulative incidence of pulmonary embolism in COVID-19 patients was qualitatively compared to: i) 196 patients hospitalized in the ICU over the same date range in 2019 (historical controls) and ii) 40 patients with influenza admitted to the ICU between January 1 and December 31, 2019.

Summary of Main Findings

Among 107 COVID-confirmed ICU patients, 34 (31.8%) received computed tomography pulmonary angiography (CTPA), of which 22 (20.6%) were diagnosed with pulmonary embolism. In comparison, 30 of 196 (15.3%) historical controls received CTPA and 12 (6.1%) were diagnosed with pulmonary embolism, and 17 of 40 (42.5%) influenza ICU patients received CTPA and 3 (7.5%) were diagnosed with pulmonary embolism. Fewer COVID-19 ICU patients had deep vein thrombosis associated with pulmonary embolism than the  historical controls or influenza patients from 2019 (13.6% vs. 58.3% and 33.4%, respectively), suggesting that COVID-19 patients may have pulmonary thrombosis instead of embolism.

Study Strengths

The authors provide the estimated cumulative incidence of pulmonary embolism, accounting for competing risks of death (n=15) and discharge alive (n=48) and censoring for patients still in the ICU (n=22). The use of two control groups provides insight into the impact of potential selection biases.

Limitations

The study includes only 107 confirmed COVID-19 patients, 22 of whom were still hospitalized in the ICU at the time of the analysis. There is potential selection bias regarding prevalence of respiratory failure among patients leading to CTPA. This study may only relate to patients with severe disease, as asymptomatic and milder cases are not represented.

Value added

Few (if any) studies have reported on pulmonary embolism frequency in COVID-19 patients.