Nicknewf, here is my understanding of how the Buffalo procedure works.
EVERYONE goes under general anesthesia for the procedure.
Severql of the comments on this thread seem to confuse general; anesthesia with sedation. Sedation for a procedure might be something that we lay people would consider ansethesia--you feel no pain, you have no memory of what happened, etc. You don't need to be "put to sleep" to remember nothing, and feel no pain. I think I had both my hernia operations done under deep sedation, and I know I had both colonoscopies I have had done under sedation, and I remember nothing about any of those procedures.
However, ansethesia involves up to 10 drugs and a patient who is truely unconscious. If a patient is under light sedation for a procedure, for example most angioplasties, he is even responsive, and the Dr. may ask him/her to cough, turn his head, etc. Yet there are drugs that are administered that produce amnisia, so the patient does not remember.
I have not been able to find out, but it is my guess that sedation with or without amnisia, is what is used since that is generally what is used for angioplasty, and that would be sufficient to blind this study since they are inserting the catheter in everyone.
General anesthesia also involves some serious risks, and I doubt an IRB would approve its use in placebo subjects.
Also, anesthisia requires the constant presence and vigilance of an anesthisiologist, a very significant expense added to each procedure that is probably not necessary.