September 7, 2020

An article review from the ESICM Journal Review Club

Thrombosis risk in patients with ARDS due to COVID-19 – higher than in patients with ARDS

COVID-19 infection due to the SARS-CoV-2 virus has shown to be associated with coagulopathy. Autopsy findings revealed thrombosis as a direct cause of death in several cases [1]. However, little is known in critically-ill patients.

In a prospective cohort study, Helms, et al [2] aimed to evaluate the risk of thrombosis in critically-ill patients with ARDS due to COVID-19 as compared to non-COVID-19 ARDS patients, all of whom received invasive mechanical ventilation in four French ICUs. Propensity score matching was also performed to compare groups.

In 150 patients, 64 clinically relevant thrombosis cases were observed, despite prophylactic (70%) or therapeutic (30%) anticoagulation. In patients with COVID-19 ARDS 18% developed thrombosis, whereas in non-COVID-19 ARDS patients 6% developed thrombo-embolic complications (p<0.001).

After propensity score matching, the difference was significant (11.7% vs 4.8%, p=0.04).

Pulmonary embolism was the most frequent thrombo-embolic complication: observed in 16.7% of patients with COVID-19 related ARDS, whereas it was found in 1.3% of non-COVID-19 ARDS patients (p<0.001).

The difference was also significant after propensity score matching (11.7% vs 2.1%, p=0.01).

In patients receiving CRRT, circuit clotting was observed in all but one case. More filters were used and lifespan was shorter in patients with COVID-19 ARDS as compared to non-COVID-19 ARDS patients.

More than 95% of the patients had elevated D-dimer and fibrinogen levels. Factor VIII, Von Willebrand Factor activity and antigen were elevated and lupus anticoagulant was positive in a significant number of patients. Disseminated intravascular coagulation was not observed according to International Society of Thrombosis and Haemostasis DIC score.



The study highlights the presence of significant coagulopathy during the course of severe COVID-19 by using imaging and coagulation tests extensively.

The main limitation of the study is its observational design revealing the prevalence of thrombosis, not defining the pathophysiological basis of increased coagulopathy in COVID-19.

The true prevalence might have been higher due to the lack of standardised protocols for indications of diagnostic tests. In addition, it is not possible to demonstrate clinical significance and effect of coagulopathy on patient outcomes.


Coagulopathy risk is increased in COVID-19, despite anticoagulation. Therefore, higher anticoagulation targets should be considered and further research is needed to delineate the underlying pathophysiology of coagulopathy and its relation to adverse outcomes in more patients.


This article review was prepared and submitted by Dr Arzu Topeli, MD, MSc, Professor of Medicine and Intensive Care in Hacettepe University Faculty of Medicine, Ankara, Turkey, and Deputy Chair of ESICM HSRO Section, on behalf of the ESICM Journal Review Club.

  1. Autopsy Findings and Venous Thromboembolism in Patients With COVID-19 – Wichmann D. et al
  2. High risk thrombosis in patients with severe SARS-CoV-2 infection: a multicenter prospective cohort study – Helms J. et al

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