My sister had a gastric bypass a couple of years ago, and unfortunately, has gained about 75% of her weight back. I've told her a lot about the sleeve and she asked me if it's possible to get a revision from Bypass to Sleeve. I had no idea. Anyone know? Thanks!

There is a good basic article on the subject over on OH:

http://www.obesityhelp.com/forums/revision/gastric-bypass-revision-surgery.html

While it seems that the more common revision is to the duodenal switch, the article says that revising to the VSG can also be done. The DS generally has better regain resistance than the RNY or VSG, so that seems to be the more common revision, but this can be an even more individual issue than choosing the original WLS. The article goes into some of the considerations in revising including analyzing why the original surgery failed and determining the appropriate response - behavior mod, reworking the original procedure or revising to another.

Another good article is this one:

http://www.dssurgery.com/about/publications/duodenal-switch-safe-operation.pdf

Revising an RNY is a complicated procedure that relatively few surgeons are qualified to do (or that one would trust to do,) so travelling is often involved. Is your sister near you in NJ? Dr. Roslin in NY is one, Rabkin and Keshisian in Calif are also well qualified. Posting to the revision board and DS board on ObesityHelp will get you some more help on this issue (even if the desired or appropriate revision is to a VSG, the folks on the DS board there tend to be very protective of their procedure and picky about surgeons' qualifications, so they can steer you to the best revision surgeons who can help guide your sister to the best answer for her.