We understand from Serana being entombed for easily over 1000 years due to her not knowing of a empire in Cyrodill. This made me think how long can a vampire survive while in a hibernation and does her being a pureblood/VL have to do with her being able to survive long periods of time without blood? Too add we know after a few decades without blood a vampire goes crazy, if they received blood after the decades would it heal them, or would it have less of an affect?

P.S. would drinking the blood of a god or a immortal being such a Vivec or a Daedra have any unique effects?

I don't believe for a minute she's actually a vampire. I see a girl with glowing eyes, nothing more.

She was obviously in a state of suspended animation, probably due to a spell that slows the heart rate dramatically or something. A shopkeeper in the Shivering Isles claimed such things are possible through Alteration. I think the enchantment broke when you opened the tomb back up again by sliding the torches around.