Futurenets,
I don't mean to be rude here, but I wouldn't be ignoring the advice from your health care team regarding the triple bypass surgery. As you already know, blocked arteries is a serious medical condition and one not to be taken lightly. My father had this procedure done and it turned his life around at that time, without the surgery he would have been dead in 2 years they said.
I would give this some serious consideration here, I don't know much about the Ornish Diet, like many other diet plans like Atkins, Bernstein etc, they are not suitable for all, and so be very careful. Often these diet plans are a means of making big money from book deals, subscriptions and media coverage, I am personally very suspicious of such deceitful methods.
I would follow the advice of the professionals, that is your gp and cardiology specialists, they are the very people that deal in such matters on a daily bases, and save countless lives as a result. Hope all goes well, which ever path you choose to follow.
Nigel