now, i dont mean to be harping on this.....but the risk of suffering an adverse event after undergoing ANY ccsvi procedure (including balloon angioplasty, or stent placement...in any country of the world by any practicioner) is currently around 2 in 1000 also. Remember, in one instance a stent migrated. In another instance, a person had a fatal reaction to a blood thinner used post-treatment.
However...with CCSVI the risk is not of dveloping brain cancer. With CCSVI the risk is likely to decrease with time, as treating doctors learn more about the procedure, diagnostics improve, etc. With Tysabri...the risk increases with time. The longer you're on it, the more risk you're exposed to.