As doctors and medical researchers continue to battle the new coronavirus, their understanding of the elusive contagion and the disease it causes appears to be making headway.
Part of this positive development is the findings of several new studies pointing to blood clots as a key reason behind serious illness and death among Covid-19 patients, with blood thinners showing promising results for severe Covid-19 infections.
A new study published in the Journal of the American College of Cardiology suggests that systemic anticoagulants (blood thinners) may be associated with improved outcomes among patients hospitalized with Covid-19.
The study looked at 2,700 patients treated at Mount Sinai in New York City, the global virus epicenter. Since the beginning of March, some patients were given anti-clotting drugs by the doctors, a treatment that worked well for most, especially those put on breathing support.
The study found a stark difference in fatality rate of patients on ventilators who were given blood thinners vs those who weren’t: Only 29% of those on anticoagulants died as compared to 63% who were not given anti-clotting drugs.
Moreover, the use of blood-thinners in Covid-19 patients was not found to have caused bleeding problems which is one of the main risks of the drug.
Mystery clots in Covid-19 patients
By the end of April, doctors worldwide were reporting cases of mysterious blood clots in coronavirus patients and resultant deaths.
Clots happen naturally in response to injuries to prevent blood loss. However, when formed in a blood vessel, they can restrict the flow of blood leading to life-threatening complications.
The condition is known as thrombus. And if a thrombus moves to other parts of the body, it creates a phenomenon known as embolus. Embolus poses a serious risk to life if it reaches the lungs, brain, or heart.
In a majority of Covid-19 cases, either phenomenon was present. Although clots tend to develop in hospitalized patients as their movement is restricted, the occurrence in coronavirus patients has been significantly high.
According to a Business Insider report, early autopsy data from Northwell Health – a nonprofit healthcare network in New York – shows major clotting events like a massive heart attack or lung clots in 40% of patients who have died after leaving the hospital.
Why this happens is not totally understood, but doctors are now beginning to put patients on blood thinners, both during and post hospitalization, addressing clotting as a concern related to Covid-19.
A right approach to Covid-19 treatment
In earlier stages of the pandemic, doctors were treating Covid-19 patients according to protocols developed for acute respiratory distress syndrome (ARDS), also known as ‘wet lung’.
However, the new findings increasingly suggest that the prevalent approach to tackling the disease may be flawed. A recent study published in the Radiology journal also corroborates this emerging thought.
A senior author of the study, Professor Edwin van Beek, said, “Worldwide, COVID-19 is being treated as a primary pulmonary disease. From the analysis of all available current medical, laboratory, and imaging data on COVID-19, it became clear that symptoms and diagnostic tests could not be explained by impaired pulmonary ventilation alone.”
The amount of a protein complex called D-dimer in the blood is a typical indication of thrombosis and embolism. The study finds a strong association between D-dimer levels of Covid-19 patients, their disease progression, and chest CT scans suggesting venous thrombosis.
In another Dutch study, researchers reported that about one-third of the 184 coronavirus patients observed in the intensive-care unit had a complication associated with a clot.
This, and many other studies suggest that physicians really need to have blood clots on their radar screen and blood thinners can play a vital role here.
Some doctors have already begun putting patients on full anti-clotting drugs as soon as they enter the emergency room, rather than lower preventive doses.
Blood-thinners ineffective against microclots
While they can be of help in preventing major blood clots, anticoagulants are not effective against microclots that some coronavirus patients develop.
These microclots are too many and hard to spot. Autopsies have shown lungs of many Covid-19 casualties filled with hundreds of microclots that regular blood-thinners don’t work against.
This, however, solved a mystery for doctors explaining why ventilators worked poorly for such patients.
While they make the patients’ lungs look like those suffering from common ARDS, it’s the tiny blood clots, not water, which cause the blood to leave with less oxygen from the lungs than it should.