Here's what I don't understand. In order to do a true, blinded study -- if I hear the phrase "placebo effect" from a doc one more time I will scream -- then they would have to do sham surgeries or I suppose you could say "pretend" to do balloon angioplasty on half the patients. Personally I wouldn't want to take part in anything like that. I'm not saying I've heard of this being done anywhere but it's an interesting point... and I'd sure as heck want to make 100% sure I'm getting the balloon.
You should check out the description of a study Zamboni, et al. are currently publishing. He described it during the NMSS web forum. Here is an excerpt from page 7 on the NMSS web site.
We also designed a pilot study together with the Buffalo group that is called endovascular treatment multiple sclerosis study. We divided our patient population in two groups. The first group underwent immediate treatment is immediate endovascular treatment group and the second group, delayed endovascular treatment group, was operated on 6 months later. So, for 6 months, you take the opportunity to measure clinical and MRI outcome with very rigorous protocol, and this is under the way of publication. We know just vascular outcome. Treatment also in this group with endovascular angioplasty was safe and well tolerated. Rate of restenosis was decreased with respect to the first study, 0 percent in the azygous, 29 percent in the internal jugular vein, and the vascular treatment MS study evaluated its clinical outcome measure, MRI conventional and non-conventional measure, including longitudinal data on iron deposition. Complete statistical analysis is under the way by an independent statistician and we plan to present this at the next ECTRIMS meeting.