The multicenter study of the Medical University of Vienna involved 568 patients hospitalized in three regions of Austria with severe symptoms of COVID-19. Of these, 71.5% received therapeutic doses of low molecular weight heparin, another 10.5% received anticoagulants that are not vitamin K antagonists (apixaban and rivaroxaban).
For 5-16 days, doctors collected blood plasma samples from patients and evaluated markers for blood clots, inflammation, and cell death. The authors of the study found that none of the anticoagulants decreased the level of D-dimer – a breakdown product of fibrin protein that is present in the blood after the destruction of a blood clot – but that the survival rate of patients treated with heparin was higher.
“Patients receiving this drug had an average of four days shorter period of infection compared to other patients. We were surprised that low molecular weight heparin can directly affect the infectivity of the coronavirus, ”the scientists said.
They added that the anticoagulant could potentially inhibit SARS-CoV-2’s ability to bind to cells, thereby preventing infection.
Previously, scientists from the United States, Canada, Germany, India and the UK investigated the effectiveness of prophylactic and therapeutic doses of heparin for patients with moderate to severe COVID-19. The results showed that a full dose of anticoagulant reduced the risk of mechanical ventilation in moderate COVID-19 patients by 98.6% compared with patients in the same group receiving prophylactic doses of the anticoagulant. Bleeding as a side effect was diagnosed in a small number of participants.
In severely ill patients, anticoagulants reduced the likelihood of thrombosis, but did not affect the need for mechanical ventilation and did not reduce the length of hospitalization.