Researchers have identified how and why some patients with Covid-19 develop life-threatening clots.

The work, which was led by a team at the RCSI University of Medicine and Health Sciences, could lead to targeted therapies that prevent these clots from happening.

Previous research had already established that blood clotting is a significant cause of death in patients with Covid-19. In order to understand why this clotting occurs, the researchers analysed blood samples taken from patients with the virus in the ICU of Dublin’s Beaumont Hospital.

They found that the balance between a molecule that causes clotting - von Willebrand Factor (VWF) - and its regulator - ADAMTS13 - is severely disrupted in patients with severe Covid-19.

When compared with control groups, the blood of Covid-19 patients had higher levels of the pro-clotting VWF molecules and lower levels of the anti-clotting ADAMTS13 regulator. Furthermore, the researchers identified other changes in proteins that caused the reduction of ADAMTS13.

According to one of the study’s authors, Dr Jamie O’Sullivan, a research lecturer at the RCSI’s Irish Centre for Vascular Biology, these findings help to provide insight into the mechanisms that cause severe blood clots in patients with Covid-19. This, he noted is “critical to developing more effective treatments”.

“While more research is needed to determine whether targets aimed at correcting the levels of ADAMTS13 and VWF may be a successful therapeutic intervention, it is important that we continue to develop therapies for patients with Covid-19.

“Covid-19 vaccines will continue to be unavailable to many people throughout the world, and it is important that we provide effective treatments to them and to those with breakthrough infections,” he commented.

Details of these findings are published in the Journal of Thrombosis and Haemostasis.