Firstly I only know of one Carotid artery on each side of the neck, not two. I would question why he said this. I think basically what has turned events is the fact that the
blockage on the left side has been seen as too much of a risk to leave alone. With no
blood supplied from the right, if the left blocks then death is imminent. I have found through experience that a Cardiologist will not say he can do something if he cannot.
He hasn't really committed himself yet, he is being cautious by saying he will perform an
investigation Angiogram first. If he feels he cannot continue due to the risks, he will stop.
Another thing you could ask your Cardiologist about is a procedure known as an endarterectomy to the vessel which was once very common. The inner layer is removed
with the disease, leaving it clean. However, this leaves a rough surface encourageing
restenosis but medication should handle that. If treatment is successfully administered
to the left side, then that means they should be able to do something to the right side
with less risk.