One in three seriously ill patients with coronavirus develop deadly blood clots

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One in three patients who fall seriously ill with a coronavirus develop dangerous blood clots that can contribute to their death, warned a leading scientist.

Clots, also known as thrombosis, can become fatal if they migrate to the main organs of the body and cut off their blood supply.

Blockages can trigger heart attacks, strokes, organ failure, and fatal pulmonary embolism.

Severe inflammation – an over-reaction of the immune system to COVID-19 infection – is thought to be the cause of blood clots.

Roopen Arya, professor of thrombosis at King’s College London, said that although pneumonia is still the leading cause of death in COVID-19 patients, doctors are now increasingly aware of the problem.

One in three patients who become seriously ill with a coronavirus develop dangerous blood clots that can contribute to their death

One in three patients who become seriously ill with a coronavirus develop dangerous blood clots that can contribute to their death

This morning, he told Radio 4 Today: “With a huge wave of data over the past few weeks, I think it has become apparent that thrombosis is a major problem.

“Particularly in critically ill Covid patients in intensive care, where some of the most recent studies show that almost half of the patients have a pulmonary embolism or a blood clot in the lungs.

Clots that start in the lower body can migrate to the lungs, causing a deadly blockage called pulmonary embolism – a common killer in patients with COVID-19.

Blockages near the heart can lead to a heart attack, another common cause of death in infected people. And clots above the chest can cause strokes.

Roopen Arya, professor of thrombosis at King's College London, said that although pneumonia is still the leading cause of death in COVID-19 patients, doctors are now increasingly aware of the problem

Roopen Arya, professor of thrombosis at King’s College London, said that, although pneumonia is still the leading cause of death in COVID-19 patients, doctors are now increasingly aware of the problem

Scientists do not know why the virus causes clots – but they think it could be the result of an excessive immune response called a “cytokine storm”.

Cytokines are chemical signaling molecules that guide a healthy immune response. They tell immune cells to attack viral molecules in the body.

But in some patients, this process becomes overloaded and the immune cells begin to destroy healthy tissue.

According to Dr. Jamie Garfield of Temple University Hospital in Philadelphia, it can cause damaged blood vessels to leak and drop blood pressure, increasing the risk of clots.

Other scientists say clots are a byproduct of how COVID-19 invades the human body.

Professor Ian Jones, virologist at the University of Reading, told MailOnline: “Covid binds to an enzyme called ACE2 which is found on the surface of the cell. It just uses it as a means of fixing itself, but in doing so, the enzymatic function of ACE2 is reduced.

“The consequence is an imbalance of the hormones called angiotensin I and angiotensin II which together regulate blood pressure. This could be linked to the increase in reported strokes. “

Dr. Robert Bonow, a professor of cardiology at Northwestern University, said it may be the unique form of the coronavirus that causes blood clotting problems.

What causes clots?

While experts don’t know why the virus is causing blockages, there are three main theories:

CYTOKINE STORM

The prevailing theory is that it is the result of an excessive immune response known as a “cytokine storm”.

Cytokines are chemical signaling molecules that guide a healthy immune response.

They tell immune cells to attack viral molecules in the body.

But in some people, this resonance goes into the overdrive and the immune cells also begin to attack healthy tissue, known as the cytokine storm.

When the blood vessels are damaged, they can leak, causing a drop in blood pressure and increasing the risk of clots.

INFECTION BY-PRODUCT

Other scientists say the increase in stroke may be a byproduct of the way COVID-19 invades the human body.

Professor Ian Jones, virologist at the University of Reading, told MailOnline: “Covid binds to an enzyme called ACE2 which is found on the surface of the cell.

“It just uses it as a way to attach itself, but in doing so, the enzyme function of ACE2 is reduced.

“The consequence is an imbalance of the hormones called angiotensin I and angiotensin II which together regulate blood pressure.

“It could be linked to the increase in reported strokes. “

UNIQUE FORM OF VIRUS

Dr. Robert Bonow, a professor of cardiology at Northwestern University, said it may be the unique form of the coronavirus that causes blood clotting problems.

He said that the tips of the virus, which lock onto cell receptors, can also attach to blood vessels.

Once they are anchored to these cells in the blood vessels, the viral particles can cause damage to them as well as to the heart muscle, says Dr. Bonow.

He told MailOnline: “With COVID in particular, what you see that you don’t have with the flu is that under a microscope, the coronavirus has all these peaks coming out, and these peaks are small proteins that look for receptors on the cells they attach to, ‘

“It specifically searches for receptors in the lungs, but these same receptors sit on the blood vessels, so it can attach to the lungs as well as to the blood vessels.”

Once they are anchored to these cells in the blood vessels, the viral particles can cause damage to them as well as to the heart muscle, says Dr. Bonow.

They can trigger “hypercoagual states”, causing blood clots that lead to heart attacks.

If COVID-19 targets blood vessels, this could explain why people who already have damaged vessels – such as diabetes and high blood pressure – are more likely to get seriously ill.

The exact way the virus attacks blood vessels remains a mystery, but several scientific articles and preprints have shown that the deadly side effect is common.

Heart damage was found in 20% of patients hospitalized in Wuhan according to a March 25 article in JAMA Cardiology.

Another study in the epicenter of the epidemic found that 44% of people in intensive care had heart arrhythmias.

Thirty-eight percent of Dutch intensive care patients had blood clotting in an April 10 study published in Thrombosis Research.

Between 20 and 40 percent of COVID-19 patients at Emory University in Atlanta, Georgia, have developed blood clots – even after being put on blood thinners.

This comes after a study by University College London which found that the coronavirus caused an increased risk of blood clots and blockages in the brain.

The small study focused on six patients with confirmed COVID-19 who had suffered a stroke caused by the sudden loss of blood flow to the brain.

The team, which included neurologists from the National Hospital of Neurology and Neurosurgery, found an increase in D-dimer – a blood protein linked to clotting.

The authors say that the exaggerated inflammatory immune response known in COVID-19 patients stimulates abnormal blood clotting in the brain.

They say there was evidence of an increase in D-dimer in the blood – that is, production of antibodies created from an abnormal immune system response.

The corresponding author, Professor David Werring and colleagues examined six patients who had an acute ischemic stroke due to blockage of a large cerebral artery.

Acute ischemic stroke is caused by the sudden loss of blood flow to an area of ​​the brain, resulting in loss of neurological function.

The results suggest that early detection of D-dimer in COVID-19 patients could allow clinicians to prescribe specific treatments at a much earlier stage.

They say it could reduce the number of people who subsequently have other strokes or blood clots elsewhere in the body.

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