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Blood clots fill lungs of black coronavirus victims, study finds

Posted May 27, 2020 10:52 p.m. EDT
Updated May 27, 2020 10:54 p.m. EDT

— Careful autopsies of 10 African-American victims of coronavirus show their lungs were clogged with blood clots, researchers reported Wednesday.

All 10 patients had underlying conditions that have been shown to worsen infection, including high blood pressure, diabetes and obesity. But genetic factors could also be at play, the team at LSU Health New Orleans School of Medicine said.

The findings, published in the Lancet Respiratory Medicine, may help explain why blacks are suffering so much more from Covid-19 in the US and in some other countries such as Britain, the researchers said.

"We found that the small vessels and capillaries in the lungs were obstructed by blood clots and associated hemorrhage that significantly contributed to decompensation and death in these patients," Dr. Richard Vander Heide, head of pathology at the medical school, said in a statement.

They also found blood markers called D-dimers, which are signs the body has been working to break down blood clots.

"I think obesity is important in our population," Vander Heide told CNN. Fat tissue activates inflammatory chemicals -- one of the mechanisms that underlies obesity's link to a variety of disease. Covid-19 infection generates even more inflammation, which doctors believe is involved in the damage caused by Covid-19 and, perhaps, the generation of blood clots.

All over the US, doctors treating Covid-19 patients are reporting their bodies are riddled with blood clots. Some early studies have shown that treating patients with anticoagulants can help.

The 10 patients all came to the hospital after having three to seven days of mild cough and fever. All suddenly collapsed or had sudden trouble breathing.

"One of the things people are seeing with Covid now is the cytokine storm that is generated by the virus," Vander Heide said. The cytokine storm is the flood of inflammatory immune system compounds some people produce in response to the infection. "We can see it in our sections of the lungs. We see the viral effects in the cells," he added.

The coronavirus itself could be causing the effect, or the patients being affected might have their own predisposition to cytokine storms and blood clotting, Vander Heide said. "There could be all kinds of genetic factors," he added.

What the pathologists did not see was inflammation of the heart, a consequence of coronavirus that doctors in China said they saw in their patients.

They also saw no evidence of what are known as secondary infections in the patients. No bacteria or fungi had jumped onto the viral bandwagon to infect them.

"We also note that two of our patients were aged 40-50 years, younger than those generally thought to be at risk of death due to Covid-19," the researchers wrote.

The findings may shed light on why blacks in general are suffering more from Covid-19 in the UK, Dennis McGonagle of the University of Leeds and colleagues wrote in a linked commentary.

"A feature of the coronavirus disease 2019 pandemic has been an increased mortality in Black, Asian, and Minority Ethnic groups in the UK, which has resulted in the UK Government setting up an emergency investigative task force," they wrote.

"In the USA, mortality from COVID-19 has been particularly high in African American communities in large cities."

A study from New Orleans in the New England Journal of Medicine, also published Wednesday, found a disproportionate number of Covid-19 hospital patients were African American. While 31% of the usual patient population at the Ochsner Health system are black, 77% of those treated for coronavirus were black, the researchers reported. And 70% of those who died were black.

"Black patients had higher prevalences of obesity, diabetes, hypertension, and chronic kidney disease than white patients," Dr. Eboni Price-Haywood and colleagues at Ochsner wrote.

But many factors likely underlie the racial discrepancies, they said.

"They may reflect underlying racial differences in the types of jobs that may have an increased risk of community exposure (e.g., service occupations)," they wrote. "Racial differences in Covid-19 that were observed may also reflect differences in the prevalence of chronic conditions that appear to increase the risk of severe illness."

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