It's extremely difficult to get a HDE. Only 10 cardiovascular devices were given the designation 1997-2015 and 2016-2022 only 5 high-risk devices have gotten the distinction for any illness in adults.
And it takes a lot of time as everything with the FDA does:
First we must generate enough data by doing ViV procedures (how many is unknown but, from my experience, the FDA does not like companies jumping the gun on these things). Then the company must apply for a Humanitarian Use Device designation, which could take as little as 45 days but often takes longer in practice.
Only then can a Humanitarian Device Exemption submission be made and getting an approval typically takes forever. The average wait time in 2015, the last year I can find data for, was 815 days. The mean wait time 2012-2016 was 671 days. Seastar Medical submitted their HDE application for acute kidney injury in pediatric patients in late July 2022 and it took the FDA until early May just to let them know that their application was lacking and needed to be submitted again.
Again, I'm not trying to be a downer, just realistic based on what I know.
https://www.meddeviceonline.com/doc/does-the-humanitarian-device-exemption-process-work-and-is-it-worth-pursuing-0001
(20min delay)