Here is another addition to the hypothesis. sandeep chakraborty on TwitterI don't doubt that ventilators are confounding the issue further, as they are meant to be used in cases such as pneumonia, which covid-19 isn't; however, doctors are finding clotting in various organs of the body.
Alarmed as COVID patients' blood thickened, New York doctors try new treatments
"At Philadelphia’s Thomas Jefferson University Hospital, Dr. Pascal Jabbour had begun to see a similar surge in strokes among people with COVID-19. The way his patients’ blood congealed reminded him of congenital conditions such as lupus, or certain cancers.
“I’ve never seen any other viruses causing that,” Jabbour said.
In Boston, the Beth Israel Deaconess Medical Center began a clinical trial earlier this month to see if tPA, an anti-clotting drug, could help severely sick COVID-19 patients.
Clotting can develop in anyone who gets very sick and spends long periods of time immobile on a ventilator, but doctors say the problem seemed to show up sooner in COVID-19 patients as a more direct consequence of the virus.
At Mount Sinai, patients in intensive care often receive the blood-thinning agent heparin in weaker prophylactic doses. Under the new protocol, higher doses of heparin normally used to dissolve clots will be given to patients before any clots are detected."
However, it seems that doctors are ignoring research that was done in as early as the 90's showing that losartan has some of the best anti-clotting properties of any drug, which seem to be separate from it's ARB properties, which is why losartan is perhaps effective, while other "sartan" drugs such as telmisartan and candesartan are not.
https://www.medpagetoday.com/infectiousdisease/covid19/86046
"our clinical observations are that extracorporeal membrane oxygenation (ECMO) circuits are clotting more, that dialysis circuits are clotting more," said Luks. "We can't explain why they're hypoxemic without a change in chest radiograph. We have seen overt pulmonary embolism or microemboli that are developing in the lungs. There's a plausible argument that maybe this is related to a pro-coagulant state."
He cautioned that studies of ARDS patients before COVID-19 do show documentation of microthrombi on autopsy, and critically ill patients do develop venous thromboembolism and pulmonary embolism and have had other issues like clotted dialysis circuits."
I think this points to the issue that doctors have drugs in mind that they think of as "anticoagulants" and they don't want to think of how drugs can be useful for issues that they weren't originally purposed for. Losartan is considered a blood pressure medication, however, it is actually effective in the use of the reduction of platelet aggregation, and moreso than almost any other medication (besides, surprise surprise, cinanserin) for GVPI-initiated aggregation (see study I mentioned above in response to yerrag).