Observations of a small number of autopsy lung incisions have been reported by physicians treating obese patients 19. Physicians have described extensive vascular damage and the presence of blood clots that would not be expected in respiratory disease.
“The difference with covid-19 is that the lungs do not stiffen or injure or destroy before hypoxia occurs,” the medical term for oxygen deprivation, says Stephen J. Menzer, a professor of surgery at Harvard Medical School and part of the team that wrote the report. “For some reason, there is a ̵
The research team compared seven lungs of patients who died of covid-19, a disease caused by coronavirus, with the lung tissue of seven patients who died of pneumonia caused by influenza. They also examined 10 lungs donated for transplantation but not used. Lungs acquired in Europe were tailored to age and gender.
In the larger blood vessels of the lungs, the number of blood clots is similar in patients with covid-19 and influenza, the researchers wrote. But in patients with covid-19, they found nine times as many micro-clots in the small capillaries of the small air sacs, which allow oxygen to pass into the bloodstream and carbon dioxide to be carried out. The virus may have damaged the walls of these capillaries and blocked the movement of these gases, the researchers wrote.
They also found inflamed and damaged cells in the lining of blood vessels in patients with a thickness of 19.
Most surprising was the evidence that the lungs of people attacked by the SARS-CoV-2 virus were growing new blood vessels.
“The lungs of patients with covid-19 have significant new vascular growth,” a finding that researchers describe as “unexpected.” In an interview, Menzer speculated that it may have been an attempt by the lungs to deliver more oxygen to the hypoxic tissue.
“This may be one of the things that makes people better,” he said.
The researchers looked for genetic and other differences that could help predict who is most susceptible to severe virus disease, but found none in their tiny sample. So far in the pandemic, covid-19 has affected certain groups, including the elderly, African Americans and people with major diseases such as diabetes, most severely.
“Patients who do quite well have a pure respiratory disease, and patients who have problems also have a vascular component,” says Menzer. But efforts to determine or explain who will fall into each group have not diminished, he said.