Faye Fulham 
1 hour ago
Solh Surman, a hematologist at Beth Israel Deaconess Medical Center, recently told me about new clues about the ominous link between Covid-19 and stroke. New clues came from the autopsy.
Only a few subjects were used in these autopsy studies-11 in one and 14 in another. Why are so few when hundreds of thousands of people die in Covid-19 around the world?
Experts say that once standard practice declined before the pandemic so that paperwork and consent became more burdensome. Currently, additional precautions are needed to protect pathologists from infection.
However, some autopsies performed revealed that Covid-19 is not a common respiratory disorder. The virus kills people by destroying the circulatory system.
To discover new therapies to test, researchers need to know more about how illness works. Some of that can be done through live clinical trials. But scientists can learn a lot from those who succumb to the virus.
And this is very different from the flu they are finding. The difference became apparent in early April. Doctors reported that some patients appeared to be breathing freely while their bodies were surprisingly starved of oxygen. With the exception of patients with extreme altitude sickness, they have never seen anything like that.
The doctors I was talking to at the time thought there was something wrong with the blood vessels that carried oxygen from the lungs. Scientists have recognized that the so-called ACE2 receptor, which puts the virus into cells, resides in the endothelial cells that line the blood vessels and control coagulation.
Later in late April, the New England Journal of Medicine published an astonishing series of case studies of five Covid-19-positive patients with stroke. All were under 50. Tragically ironically, some were afraid to go to the hospital to get Covid-19. Not to mention that they are already infected with the virus, not to mention that they may be the cause of the symptoms.
“We’re continuing to collect data on stroke patients and we’ve learned a lot about how Covid-19 causes blood clots in other parts of the body,” said a neurovascular physician at Mount Sinai Health System. According to Johanna Fifi, the author of that article. Blood clots can also be found in the lungs and kidneys. “Coagulation seems to be a very prominent feature of this disease,” she says.
“It causes more thrombosis than any other virus,” says Pascal Jabul, a doctor at Thomas Jefferson University Hospital. “Never seen” Jabbour also collects data on stroke patients, showing that Covid-19-positive cases are young and survive after thrombectomy with routine surgical treatment I found it unlikely. Mortality is about 43%, and in the normal case about 5%.
Schulman says there is growing evidence that Covid-19 affects blood vessels in people who have no apparent symptoms of stroke or blood clots. People with severe Covid-19 have an off-the-chart high blood marker associated with blood clotting called D-dimer. Approximately 500 levels represent a significant thrombotic risk, but severe Covid-19 patients “represent the highest number most of us have ever seen,” he says. The D-dimer test only measures levels up to 22,000, which many patients clearly exceed.
Now, thanks to the people who donated their bodies to science, doctors are better able to understand what is happening. One paper, published in the Annals of Internal Medicine, recorded autopsies of 11 randomly selected Covid-19 patients. There was all 11 evidence of pulmonary artery thrombosis-thrombus. No one was diagnosed with a blood clot during life.
The fact that these people were randomly selected is significant, Schulman says. What researchers see in patients with Covid-19 looks different than what they see in patients who suffer from common strokes and blood clots in the lungs. In deceased Covid-19 patients, blood clots appeared to have formed within the lungs themselves, but more commonly elsewhere, where they cleaved and reached the lungs. Moreover, in Covid-19 patients, it was the small blood vessels that were blocked-the sidewalks, rather than the main highways (like a typical stroke).
Another autopsy study, published in the New England Journal of Medicine in late May, compared seven patients who died of Covid-19 with seven who died of H1N1 influenza. In those who died of Covid-19, the damage to the cells lining the blood vessels was many times more extensive.
Schulman says this can be caused by the virus itself, or by an overreaction of the immune system when the body tries to fight off the virus. The immune system is intertwined with the blood coagulation system. He explains that coagulation is a primitive immune response that provides enzymes that cause blood to gel in animals, essentially destroying the barrier to bacterial invasion.
Jabbour agrees that an immune hyperreactivity, sometimes called a cytokine storm, is likely involved. One consequence of such an overreaction is the release of proteins known to regulate the coagulation system. It may also explain the circulatory problems that cause discolored “Covid toes” and the inflammatory response seen in some children that resembles a condition called Kawasaki Syndrome.
A new understanding of the vascular side of this virus has already changed the standard of care. Many patients are currently receiving anticoagulants as part of their treatment, and others are enrolled in clinical trials to test the efficacy of these drugs. To continue to learn more about this disease and how to treat it, doctors will not only need more time, but more research of all kinds-one living and one lost. About both.
Bloomberg
