COVID-19 & Blood Clots: Is There A Link?

Clotting of blood is a natural response of the body to any open wound or injury. A Blood Clot develops when the blood changes into a semi-solid state at the site of the injury or wound to prevent any excess blood loss. There are various chemical processes that results in clotting of blood. Once the wound heals the clot dissolves on its own.

It is quite common to see blood clots on the skin surface after an injury. However, sometimes, blood clots can form in veins which can be very serious and life threatening. These types of blood clots do not dissolve spontaneously and in fact impair adequate blood flow through the vein. This at times can even be fatal for the person.[1, 2, 3]

Sometimes, a clot formed at a particular part of the body can break off and get lodged in some other part. This is medically known as embolism. If this clot reaches the brain, heart, or lungs it can cause extremely serious complications like a stroke or a myocardial infarction. Some of the symptoms of embolism include persistent cough, hemoptysis, severe pain in the extremities, acute chest pains and shortness of breath.[1, 2, 3]

With regard to blood clots and the relationship that it shares with COVID-19 is being much talked about by researchers these days. There is continued evidence emerging that COVID-19 can indeed cause blood clots. This has been seen in about 30% of critically ill patients who have a known diagnosis of COVID-19.[1, 2, 3]

Some researchers are of the belief that blood clotting is one of the primary features of COVID-19 but what has baffled them the most is the presentation of the blood clots and not the presence of it.[1, 2, 3] This article throws more light into the relationship between COVID-19 infection and blood clots.

COVID-19 & Blood Clots: Is There A Link?

An article in Nature mentions that researchers are still not sure as to why COVID-19 causes blood clots. However, they have come up with multiple theories. According to one theory, clotting occurs when the virus attacks the endothelial cells lining the blood vessels. During this process the virus binds to the ACE2 receptors that are naturally present in the endothelial cell membrane. Once the binding process is over, the blood vessels start releasing a protein that promotes blood clotting.[3]

Another theory suggests that COVID-19 causes the immune system to trigger an inflammatory response. This inflammatory response in turn triggers clotting. There are other external factors as well that are at play in people with COVID-19 who develop clotting. These include age above 65, being overweight, history of hypertension and diabetes, and being on medications that increase likelihood of blood clotting.[3]

Researchers suggest that the blood clotting that is seen in people with COVID-19 is quite different from that seen in people without this condition who have had history of stroke or pulmonary embolism. It has been observed that the blood clots in people with COVID-19 form in the lungs, which is not the case normally. A blood clot generally forms at other part of the body which then breaks off and gets lodged in the lungs. The clots seen in people with COVID-19 tend to form in small blood vessels of the lungs instead of major blood vessels such as that seen in people with stroke.[3]

There is also one study which consists of data of 11 people who succumbed to COVID-19. The autopsy review of these 11 people clearly states that all of them had blood clots but they never received a diagnosis of it when they were alive. After examining the data, the researchers were of the view that these blood clots were the actual cause of death in these 11 people even though 10 of them did receive anticoagulation medications.[3]

Researchers are also of the opinion that excessive blood clotting in COVID-19 patients is one of the primary causes of major complications that are seen from this infection. Research studies also indicate that people with COVID-19 who have blood clots are more likely to need intensive care treatment and have far worse prognosis than people who do not have it.[3]

What Are The Current And Upcoming Treatments?

Almost all COVID-19 patients are now being given blood thinners and anticoagulation medications. This is done while the patient is in the hospital and is recommended to continue for at least two weeks after discharge to minimize the risk of blood clots due to COVID-19. However being on blood thinners increase the chances of easy bleeding and thus these medications are not suited for high risk people.[3]

There have been reports of some people who were on ventilators due to COVID-19 and were also on blood thinners had lower chances of surviving than people who did not take blood thinners. New avenues and therapies are now being looked at to try and prevent and treat blood clots that are caused due to COVID-19. Researchers are comparing standard doses of blood thinners with higher doses that are given to critically ill patients. More potent medications like plasminogen activators are also being tested to treat blood clots due to COVID-19.[3]

In conclusion, there is no clear reason known to researchers as to why COVID-19 causes blood clots in some patients. They have come up with some theories which have been detailed above that might be the reason as to why COVID-19 patients develop blood clots.[1, 2, 3]

A unique thing that is known about the blood clots formed due to COVID-19 is that in almost all the cases the clots are formed in the lungs and that too in small blood vessels and the major vessels are spared. This is not the case in people with a history of blood clots but without COVID-19. As of now, new avenues with more potent drugs and therapies are being looked at to not only treat but also prevent formation of blood clots in people with COVID-19 to improve their chances of survival and beat this pandemic successfully.[1, 2, 3]

References:

Also Read: