Before I switched to industry and communications, I was in the medical racket. My degree was in biomedical engineering and I was working permanent part time at the Cleveland Clinic on the research side designing micro based controllers for their pumps (artificial hearts.) In 82-83 timeframe they had a steady state pump they were testing in cows. The main problem at the time was creating an impeller that simultaneously would not damage blood cells and not create dead spots behind it. Clots would form behind the impeller because of the lower pressure and when they got big enough, would throw an embolism. The positive side was that the steady state was a lot easier on the vascular system. There was some speculation that the steady state might allow build up in the capillaries over a longer period of time.
I left the medical dodge in 83, so they've had plenty of time to work on the problem.