Our neighbor's mom stroked out during an angiogram; left her with very poor vision for the rest of her life.
The hospital I worked for was a Harvard Medical School teaching hospital...considered to be one of the best in the world.I can assure you that even at the very best hospitals there's no iron clad guarantee that everything will go right.There are very,very few...if any..."sure things" in medicine.
My Grandma went in for an Angiogram, and her heart stopped. They were not able to revive her.