Abnormal blood clotting in COVID-19 patients: Researchers at Yale Cancer Centre explain why it occurs and how it could be detected early

Since the first COVID-19 case emerged in Wuhan in December last year, over 11 million people have tested positive globally while the number of deaths due to the novel coronavirus has crossed 5 lakhs. Doctors have reported that abnormal clotting of blood and cytokine storm are two of the most common reasons behind the death of COVID-19 patients. Studies have concluded that many of the COVID-19 patients admitted to hospitals had increased D-dimer levels at the time of admission. Increased D-dimer levels indicate an increased risk of abnormal blood clotting. In a recent study, led by the Yale Cancer Centre, doctors revealed that they have found the reason for the abnormal blood clotting in COVID-19 patients. They further stated that with the help of a protein, also found in their study, they will be able to find out which COVID-19 patient would be more prone to blood clots. Yale Cancer Centre research: Abnormal clotting of blood Various previous studies have already shown that critically ill patients with COVID-19 infection have increased levels of von Willebrand factor (VWF) in their blood. VWF is one of the clotting factors responsible for the clotting of blood. In this study published in The Lancet Haematology on 30 June 2020, the scientists studied both critical and non-critical patients with COVID-19 infection. The researchers tested 68 patients who were confirmed cases of COVID-19 infection and were included in the study from 13  April to 24 April 2020. Out of those 68 patients, 48 were admitted to the ICU, 20 were non-ICU patients and 13 were non-hospitalised as they were asymptomatic. The doctors then collected blood samples from the veins of these patients, which was tested for all the clotting factors and other aspects. The results of the study showed that people who were non-critical also showed high levels of VWF. The study also showed that these people also had high levels of plasminogen activator inhibitor-1, which allows the blood clots to remain intact. Endotheliopathy: Reason behind the abnormal clotting of blood To find out the reason for this abnormal clotting of blood, the scientists tested the markers of endothelial cell (inner lining of all blood vessels) and platelet activation. These markers were soluble P-selectin, sCD40L and soluble thrombomodulin. An intact endothelial cell lining prevents the clotting of blood. P-selectin and thrombomodulin are proteins that are present on the endothelial cells and prevent the coagulation of blood. These proteins are only released in the blood whenever there is any injury to the endothelial cells. These markers were tested in 40 ICU patients, 10 non-ICU patients and 13 non-COVID-19, non-hospitalised patients. The test results showed that people with low levels of soluble P-selectin and soluble thrombomodulin were discharged and sent home whereas the ones (especially the people in ICU) with high levels of these proteins were at the risk of high mortality. Conclusion The scientists stated that the markers of endothelial cell and platelet activation were significantly higher in ICU patients compared with non-ICU patients. They also found that VWF and soluble P-selectin were also increased in critical patients. The scientists concluded that abnormal clotting in COVID-19 patients could be due to endothelial cells damage and platelet activation. They further added that risk of clotting can be predicted early by measuring the levels of P-selectin, thrombomodulin, sCD40L and VWF in the blood samples of COVID-19 patients. For more information, read our article on Complications of Severe COVID-19 infection. Health articles in Firstpost are written by myUpchar.com, India’s first and biggest resource for verified medical information. At myUpchar, researchers and journalists work with doctors to bring you information on all things health.