It may have to do with the location of the blockage. A vascular surgeon is usually the professional to perform the procedures (likely a carotid endardectomy) which has many risks. Make sure you know of the risks.
First, I'm so sorry to hear your mother had a stroke. This must be terrible for you. However, it seems she's doing very well regarding recovery and you should take heart in this. She will no doubt make a total recovery, and after her surgery, her health will improve significantly.
Yes, a vascular surgeon is the person to perform an endarterectomy (removing the plaque from a blocked artery). Generally, only arteries that are 75% - 99% are surgically unblocked. Arteries that are 100% blocked are not surgically unblocked because when the blockage is complete, there is a high risk of stroke or brain damage during the surgery. To be truthful with you, there is a low, 1-3% chance of stroke during any endarterectomy, however most people come through it just fine and are home within a few days, with total blood flow in the affected artery restored. Senator Edward Kennedy just recently underwent the procedure and was home and feeling fine within a few days. Some people come home the very same day of their surgery. There are steps a vascular surgeon can take to reduce the risk of stroke during surgery and you need to talk to him or her about these.
It's important that you get the best vascular surgeon available for your mother. After her surgery, she will probably be put on daily aspirin therapy or blood thinners to prevent problems from the artery that is 100% blocked. Usually, people on these medications do extremely well, however they need to make some lifestyle changes, if possible. If your mother can walk, she should exercise. If she smokes, she needs to stop. If she has diabetes, it needs to be carefully monitored. Her diet should be one that promotes a healthy cholesterol level. Please talk to your doctor about these things.
I know this is very scary for you, but please be assured that your mother is doing fantastically and that the risk during surgery is very low. Please take heart in the positives (and there are many in your mother's case) and good luck to both of you. I wish you the very best.
Your mother's 100% blocked artery cannot be unblocked since, as the previous post said, it is more dangerous to unblock a chronically blocked artery than the one that is just partially blocked. There is a good chance that she no longer relies on the blocked artery yet her 75% blocked artery is likely doing most of the work. If that is the case, she needs her 75% blocked artery treated carefully. A vascular surgeon or a neurosurgeon can perform this surgery. You should do it at a place with good neurology service as well as where they perform these surgeries routinely. There are surgical options for helping out the 100% blocked artery but those are not always necessary and also carry higher risk of perioperative stroke. The safest bet if your mother is doing well now is to plan for unblocking of the 75% side.
Thank You all for the encouraging words of hope it means so much to me God Bless You All!!