Autopsies of 10 African American victims of coronavirus in New Orleans show that the insides of their lungs were riddled with blood clots, adding to evidence that COVID-19 stokes damage in the body far beyond a typical respiratory illness.
Researchers from LSU Health Sciences began carefully examining victims of coronavirus in mid-March, less than a week after the first death in New Orleans. At University Medical Center, which was built after Hurricane Katrina equipped with a morgue designed to contain and study infectious diseases, the researchers focused on sections of patient lungs because the virus was believed at the time to be primarily a respiratory illness.
They didn’t need a microscope to see that blood clots likely contributed to the deterioration of patients. Black dots lining the small blood vessels and tiny capillaries inside the lungs told researchers that COVID-19 was much more than a severe form of pneumonia.
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“Immediately upon looking at the lungs, even without a microscopic exam, it was clear there was a problem with small clots and hemorrhage,” said Dr. Sharon Fox, an associate director in the pathology department at the medical school and author of the study detailing the findings published in The Lancet on Wednesday.
By early April, the LSU researchers saw a pattern: The first 10 people autopsied showed signs that issues with blood clotting in small vessels in the lungs contributed to their death. All were African American with severe coronavirus infections, and at least one underlying health condition, such as obesity, medication-controlled high blood pressure or diabetes. The patients did not have signs of hospital-acquired infection from being on a ventilator or inflammation of the heart, which researchers in China reported in coronavirus patients.
The association of blood clots with coronavirus was initially surprising, but recent research from around the world indicates clots are prominent in severely-ill patients.
“Five months ago when initially hearing about the disease from China, we barely thought about this as a vascular pathology or blood clots being a feature of the disease,” said Dr. Behnood Bikdeli of Columbia University’s Irving Medical Center, who was not involved in this study. After witnessing multiple heart attacks and strokes in patients in New York, Bikdeli said a subgroup of patients in the ICU — perhaps 15% to 20% — would die from clotting issues.
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“Yes, the lungs are the major organ being infected. But it’s a multisystem, multiorgan disease,” said Bikdeli, who collaborated with more than 40 experts to create guidelines for treating clots in COVID-19 patients. “Blood clots are probably one of the major hallmarks.”
The clots can damage the body in a number of ways. If the clot travels to the brain, it can cause a stroke. If it travels to the heart, it can cause a heart attack. In the lungs and small blood vessels, the clots can prevent blood flow and the exchange of gases within the lungs, making it hard for people to get enough oxygen into their bloodstream.
The researchers have since autopsied 26 people. Twenty-two of those were African Americans. The findings may also help explain why black people are experiencing more severe complications and more deaths related to coronavirus, said Dr. Richard Vander Heide, head of pathology at the medical school and a study author.
“This population has something different that makes it worse when they get this disease,” he said, adding that more information from the autopsies may help determine if there is a genetic factor at play.
Another autopsy study of 12 patients in Germany published in the Annals of Internal Medicine found that seven had undiagnosed deep-vein thrombosis, a blood clot in the leg that often breaks off and travels to the lungs, causing a pulmonary embolism. Ten of the 12 patients had elevated levels of a protein that indicates the body is attempting to dissolve clots.
It’s not clear why COVID-19 is causing blood clots, but researchers think it may have to do with the inflammatory response and the way coronavirus infects the cells of blood vessels.
In COVID-19 patients, the lining of blood vessels becomes injured by the infection and can trigger what’s known as a cytokine storm — an overreaction of the immune system that causes chemical messengers and compounds to flood the body.
“When they’re activated all at once, it causes things to get worse,” said Vander Heide. Blood clots can form as a result.
As a result of the study and similar conclusions from other researchers, patients can expect closer monitoring of blood clot formation through laboratory tests that measure the body’s response to a clot. It is possible that anti-coagulants delivered earlier or in higher doses may mitigate the risk of a clot, said Fox. The presence of clots would change the way patients are treated.
“There are drugs being studied,” said Fox. “It might lead to more blood testing, more awareness and possibly an earlier treatment.”