I assume you mean Arteries?
With the back of the heart so blocked, I assume that medication is not having much effect? I would personally try and find an intervention cardiologist who is willing to stent the blockages. I say that mainly because the back of the heart is a harder job when it comes to bypass surgery than the left or right side.
Hi Jim!
I believe there's quite a bit that can be done to alleviate the blockages and it's good that they've been found!
I'll leave more sophisticated answers to the more experienced people on this forum. All the best :-)