COVID-19 Evidence Alerts
from McMaster PLUSTM

Current best evidence for clinical care (more info)

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Treatment Lemos ACB, do Espirito Santo DA, Salvetti MC, et al. Therapeutic versus prophylactic anticoagulation for severe COVID-19: A randomized phase II clinical trial (HESACOVID). Thromb Res. 2020 Dec;196:359-366. doi: 10.1016/j.thromres.2020.09.026. Epub 2020 Sep 21.

INTRODUCTION: Coronavirus disease 2019 (COVID-19) causes a hypercoagulable state. Several autopsy studies have found microthrombi in pulmonary circulation.

METHODS: In this randomized, open-label, phase II study, we randomized COVID-19 patients requiring mechanical ventilation to receive either therapeutic enoxaparin or the standard anticoagulant thromboprophylaxis. We evaluated the gas exchange over time through the ratio of partial pressure of arterial oxygen (PaO2) to the fraction of inspired oxygen (FiO2) at baseline, 7, and 14 days after randomization, the time until successful liberation from mechanical ventilation, and the ventilator-free days.

RESULTS: Ten patients were assigned to the therapeutic enoxaparin and ten patients to prophylactic anticoagulation. There was a statistically significant increase in the PaO2/FiO2 ratio over time in the therapeutic group (163 [95% confidence interval - CI 133-193] at baseline, 209 [95% CI 171-247] after 7 days, and 261 [95% CI 230-293] after 14 days), p = 0.0004. In contrast, we did not observe this improvement over time in the prophylactic group (184 [95% CI 146-222] at baseline, 168 [95% CI 142-195] after 7 days, and 195 [95% CI 128-262] after 14 days), p = 0.487. Patients of the therapeutic group had a higher ratio of successful liberation from mechanical ventilation (hazard ratio: 4.0 [95% CI 1.035-15.053]), p = 0.031 and more ventilator-free days (15 days [interquartile range IQR 6-16] versus 0 days [IQR 0-11]), p = 0.028 when compared to the prophylactic group.

CONCLUSION: Therapeutic enoxaparin improves gas exchange and decreases the need for mechanical ventilation in severe COVID-19.


Discipline / Specialty Area Score
Intensivist/Critical Care
Hemostasis and Thrombosis
Comments from MORE raters

Intensivist/Critical Care rater

This is definitely new and relevant information.

Intensivist/Critical Care rater

This is a clinically relevant, current question and topic. However the findings are hampered by significant methodological limitations, including the limited sample size and the open-label design.