I´ll write you again. Sorry I didn´t have any time.
Dr. Ameriso
If your mother has symptoms i.e. chest pain and there is relief with medicaion, then medication should be the option of choice according to ACC/AHA guidelines. Lesions less than 70% usually don't require any treatment.
The next option would be stent implants. If stents cannot be considered because of location, size, or an emergency, then a bypass.
I have a totally blocked LAD and 72% Lcx blockage, and I have been on a regimen of medication, diet, exercise, etc. without any problems.