Dino, this is a decision only you can make. Tysabri is a mainstream somewhat effective treatment with some risk. CCSVI is still outside the mainstream, has very little risk, and appears to have great promise. I can't see any reason why you can't go for the liberation procedure while on Tysabri, I believe there are several people in this category.
What I would do (realize I'm not a medical person)
1. Make lifestyle changes - like the best bet diet.
2. Go for the liberation procedure.
3. THEN decide if you want to be on Tysabri.