"Ventilators is not the ultimate goal. Many patients are dying despite being on ventilators. This is not mere pneumonia that is troublesome, something else is also troublesome - coagulation in blood vessels is the problem", Dr Mathew Varghese, Veteran Orthopaedic Surgeon, known for his contribution in eradicating polio, told FIT.
It has been over four months since the first COVID-19 case, but experts from all around the world are still discovering more about coronavirus manifestations every passing day.
What was initially seen as a respiratory disease alone has turned out to be much more. One such complication is related to abnormal blood clotting in severe patients. In fact, some of its presentations are rather atypical and unusual, critical care experts tell us.
The initial reports of a few COVID-19 patients behaving mysteriously normal even at a very low oxygen level had puzzled many. Further, when mechanical support or ventilators couldn't counter this complexity in some of these patients and stop a few from dying, experts dived deep into the potential causes. It turned out a subset of coronavirus infected patients are developing what's called thrombosis or formation of blood clots within the blood vessels - which is also the possible reason for kidney damage, neurological issues such as strokes as reported by FIT earlier, and heart-related problems.
When blood vessels are blocked due to clots, blood and oxygen are restricted and can't flow - leading to fatal issues in some patients. In some cases, these clots can also break into smaller parts and travel to the brain and heart causing strokes and heart attacks.
Autopsy reports too have shown COVID-19 has a role in inducing coagulopathy and some people's lungs were filled with many micro-clots. As a result, some severe patients are been given anticoagulants and blood thinner as prophylaxis to fight the challenge. Studies have shown some promise as well.
In a new guideline for COVID-19 related death reporting, the Indian Council of Medical Research (ICMR) also acknowledged blood clotting in blood vessels as a cause of deaths. It says, "COVID-19 is reported to cause pneumonia / acute respiratory distress syndrome (ARDS), cardiac injury, disseminated intravascular coagulation and so on. These may lead to death."
What's Happening?
In a study done in the Netherlands involving 184 ICU patients with proven COVID-19 pneumonia of whom 23 died (13%), 22 were discharged (12%) and 139 (76%) were still in the ICU on 5 April, 31% incidence of thrombotic complications were observed. It further said, pulmonary embolism (PE) - a blockage of an artery in the lungs - was the most frequent thrombotic complication.
These blood disorders were also observed in China, early reports had suggested. A report from China in February said abnormal coagulation results are common in deaths with novel coronavirus pneumonia.
It is important to note that blood disorders are not unique to COVID-19.
Dr Sumit Ray, Critical Care Specialist told us,
Some experts relate this phenomenon with sepsis where the body's immune system starts reacting to infection and either develops blood clotting or disseminated intravascular coagulation (DIC) which means excessive bleeding due to exhaustion of blood-clotting substances.
Dr Ray clarifies, "In COVID, the predominant aspect relatively is the more clot formation along the major and larger blood vessels which is unusual than sepsis. In sepsis, mostly the clots block the smaller blood vessels."
At this point, it is not entirely known why these clot incidents are higher in COVID-19 patients. Apart from the body's immune system reacting aggressively and going overboard (cytokine storm), the other potential cause is SARS-CoV-2 directly attacking the endothelial cells that line the blood vessels.
According to a study published on The Lancet, the virus "can directly infect engineered human blood vessels."
Blood Thinners 'Show Promise'
"We are already using blood thinners" for some critical patients, told Dr Shiva Ayyar, Head of Critical Care at Bharati Hospital, Bharatiya Vidyapeeth Medical College, Pune told FIT.
He further added, "Greater vigilance and giving blood-thinning medications is what is required. It can have an impact on brain, heart, other organs and also result in bleeding if clotting factors are used up."
The early reports from Netherland and China also recommended the use of blood-thinners for patients in ICU.
A study at a New York hospital involving 2,733 patients found out that using blood thinner can boost the chances of survival for severe COVID-19 patients.
The results were published on 6 May in the Journal of the American College of Cardiology. Valentin Fuster, a physician in chief at Mount Sinai Hospital and one of the study’s authors said, “My opinion is cautious, but I must tell you I think this is going to help.”
“This is the opening of the door for what drugs to use and what questions to answer”, he added.
It found out that among patients who were not on ventilators, the ones who were given the blood thinner treatment lived longer in comparison to the ones who were not given. Further, among patients who were on ventilators, 63 percent who did not receive the treatment died compared with 29 percent who received it.
While experts think blood thinner and anticoagulants can ensure blood doesn't clot, they also suggest a conservative approach in terms of recommending the doses.
Dr Ray told us, bleeding can be a side effect of blood thinners. There has to be a balance between blood-thinning and clotting.
Dr Mathew Varghese told us, "When there is coagulation happening in the lung tissue, fibrin is formed. The body likes to correct that so it breaks down the fibrin slowly by a process. The breakdown product is called a d-dimer. When coagulation takes place, d-dimer levels shoot up. They are using this as a marker now in COVID-19 patients when they become breathless. When they find d-dimer is high, on a trial basis, they are giving anticoagulants."
It is seen that a high level of d-dimer can be used as an indication and can be helpful in deciding the doses. According to a study, a high level of d-dimer was observed in some COVID-19 severe patients. The study said, "it could effectively predict in-hospital mortality in patients."
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