COVID-19 is ... affecting the thin layer of flat cells lining the inside of blood vessels. The cells spill their contents, and small blood clots form that morph into bigger ones.
American and Canadian doctors are seeing signs of blood clotting covid- 19 in their patients, sometimes leading to severe outcomes. Could help? blood thinners
Not only was it scary that people were dying from COVID-19. For cardiologist Anu Lala and her colleagues at Manhattan’s Mount Sinai Hospital, what was particularly frightening was seeing younger patients die, suddenly.
Some were dying like how people die when they have an acute pulmonary embolism, a large blood clot in the lungs, Lala said. Within minutes, they were gone.
“Resuscitative efforts felt futile,” said Lala, an assistant professor of medicine at the Icahn School of Medicine at Mount Sinai. On mobile monitors they had “pulseless electrical activity,” a heart rhythm, but no pulse. Trying to jump- start the heart just doesn’t work in these scenarios. “It can be difficult to bring these patients back.”
Lala observed what she assumed were blood clots in the arms and legs of COVID-19 patients. A colleague was reporting strokes in healthy young people in their 30s and 40s. On imaging tests, doctors were seeing parts of lungs not filled with blood. On autopsy, pathologists noted lungs, livers and kidneys choked with micro clots.
Now, a brief report by Lala and her colleagues suggests common blood thinners might improve survival for people suffering severe COVID-19. The study appears in the Journal of the American College of Cardiology.
The team reviewed 2,773 confirmed cases of COVID-19 admitted to five New York City hospitals between March 14 and April 11. They looked at survival rates of people placed on a blood thinner called an anticoagulant.
In all, 28 per cent of the people received a full- treatment dose of blood thinners, a higher dose than what’s typically given to prevent clots. Overall, the death rate was slightly lower for people treated with blood thinners than those who didn’t receive the drugs (22.5 per cent versus 22.8 per cent.)
However, when they looked at patients on ventilators in ICU, the benefits seemed more dramatic: 63 per cent of intubated patients who weren’t given a blood thinner died, versus 29 per cent who were given the medications.
Mechanically ventilated patients are sicker “and it’s possible that we’re seeing a greater difference in those patients because they’re sicker and more likely to develop blood clots,” Lala said.
What seems clearer is that COVID-19 is looking more like an endothelial disorder, meaning it’s affecting the thin layer of flat cells lining the inside of blood vessels. The cells spill their contents, and small blood clots form that morph into bigger ones.
It could be a direct effect of the virus itself, or the fallout of an immune overreaction. “We don’t know yet,” Lala said. “By no means am I saying we should start anti- coagulation therapy on everybody.”
Blood thinners increase the risk of serious bleeding, though the risk of major bleeding was only slightly higher in the treated group. It’s about weighing the benefits versus the risks, she said. And more work needs to be done to flush it out. However, Mount Sinai is now sending recovered people home with a short course of blood thinners.
According to a brief article published in the Canadian Medical Association Journal, 20 to 55 per cent of people admitted to hospital with COVID-19 have lab evidence of clotting problems.
“The controversy is that some doctors are responding emotionally and instead of waiting for scientific evidence, they’re providing therapeutic doses, now,” said Dr. Michelle Sholzberg, a hematologist at St. Michael’s Hospital in Toronto.
Sholzberg is principal investigator on the RAPIDCOVID COAG trial, which is randomizing people hospitalized with COVID-19 to receive low or high dose blood thinners. “We have to know if this works, because if it works we can start treating immediately. And if it isn’t safe to provide, it’s also urgent that we know this.”