Chelation therapy does not remove "plaques". Depending on the chelating agent ( there are a few) Chelation removes specific things from blood. It removes circulating things ( such as heavy metals) not from specific organs just from the liquid blood.
A person can have too much iron in their brain but still be anemic and have a low serum iron. The known iron chelators do not "pull iron" out of tissue (like the parenchyma of the brain).
But there are several things that you can do post- angioplasty- they are all listed on www.ccsvi.org
"Helping Myself" section
They make sense too- Healthy eating, good hydration, restful sleep, regular exercise, no smoking , avoiding caffiene and vaso-constrictors,
Maybe some day there will be a way to remove the iron/debris from the brain, but right now you have to rely on your own immune system and heal the endothelium of your vessels. Also remember that endothelium heals relatively fast but myelin takes many months.
Best of Luck.