Maybe check out Dr. Sclafani's thread? He seems to think of angioplasty as a minor procedure with low risks. He also describes in detail what the whole process is. I haven't heard any talk of weight being a risk factor. I know clotting is a risk after angioplasty and while I don't mean to speculate maybe a clot could then cause a stroke or a coma? But that is why the doctor will probably prescribe blood thinners.
"However, the truth in science ultimately emerges, although sometimes it takes a very long time," Arthur Silverstein, Autoimmunity: A History of the Early Struggle for Recognition