Not really. We know that oxygen-starved brain quickly destroys itself in minutes, unless very cold. So even if you can revive a brain after hours, it will not be a very good brain.
Why would anyone wait a few hours after death to do the technique? Wouldn't it make more sense to do it right away, and get the brain into its new medium? Right now there's all the limitations of something that's a nascent technology, but the methods should surely be improved as time goes on.
Cause it takes time to get to the hospital that does the procedure and it takes time to start the procedure.