On the other hand, critically ill patients with COVID-19 and low levels of factor V appear to be at increased risk for death from a coagulopathy that resembles disseminated intravascular coagulation (DIC).
DIC is a devastating, often fatal abnormality in which blood clots form in small vessels throughout the body, leading to exhaustion of clotting factors and proteins that control coagulation.
These findings point to disturbances in factor V activity as a potential cause of blood clotting disorders with COVID-19.
The study is from Massachusetts General Hospital (MGH). One author is Elizabeth M. Van Cott, MD.
Patients with severe COVID-19 disease can develop blood clots in medical lines (intravenous lines, catheters, etc), and in arteries, lungs, and extremities, including the toes.
Previously, the team had found that a blood sample from a patient with severe COVID-19 on a ventilator contained factor V levels high above the normal reference range.
Four days later, this patient developed a potentially fatal blood clot occurring at the junction of the left and right pulmonary arteries.
In this study, the team examined the levels of clotting factors in 102 patients with COVID-19.
They found that factor V levels were much higher among patients with COVID-19 compared with controls and that the link between high factor V activity and COVID-19 was the strongest.
In all, 33% of patients with factor V activity well above the reference range had either deep vein thrombosis or a pulmonary embolism, compared with only 13% of patients with lower levels.
Death rates were much higher for patients with lower levels of factor V (30% vs. 12%), with evidence that this was due to a clinical decline toward a DIC-like state.
The researchers note that factor V elevation in COVID-19 could cause misdiagnosis of some patients because under normal circumstances factor V levels are low in the presence of liver dysfunction or DIC.
Doctors might therefore mistakenly assume that patients instead have a deficiency in vitamin K.