I have question about my H1B visa restamping.

I have changed the job from original company A to Company B.

First stamping in passport done by Company A which is visa valid up to Sep 2013.


I have transfer H1B visa from A to B.

I have to travel india for personal reason..

Do I need to go for re stamping for new employer B to travel back to USA or just approved I797 approval along with old visa present in the Passport is enough to enter USA?

Thanks
Subbu