Utilizing nanotechnology could completely control cell degeneration and eventually eradicate the aging process, which leads to clinical death.
Ultimately, only the most extreme accident/murder cases would need to be cryonically preserved in biostasis, until the medical communities were able to reanimate the deceased (injured) person for final repairs.
Nanotechnology and Cryonics Cryonics Institute -- Feature Article: Nanotechnology and Cryonics