Amy Rapkiewicz, the chairman of the department of pathology at NYU Langone Medical Center, spoke to Erin Burnett on OutFront Thursday night.

Some Covid-19 patients are known to develop blood clotting issues, but the degree and the extent to which that occurs was described as "dramatic" by Rapkiewicz.

In the early stages of the pandemic, bedside clinicians noticed a lot of blood clotting "in lines and various large vessels," she said.

"What we saw at autopsy was sort of an extension of that," she said.

"The clotting was not only in the large vessels but also in the smaller vessels.

"And this was dramatic, because though we might have expected it in the lungs, we found it in almost every organ that we looked at in our autopsy study," she said.

Rapkiewicz's study outlining her findings was published at the end of June in The Lancet journal EClinicalMedicine.

The autopsies also showed something unusual about megakaryocytes, or large bone marrow cells.