Well from looking at the report, and taking into account your Mothers quite young age, this is a difficult one. The Cardiologist may be looking more long term, but for now there is really only one section that requires immediate attention, the mid LAD of 90%. I know Cardiologists can sell an opinion very well, but there are no guarantees with any procedure for the long term. I had a triple bypass which only lasted 3 months and I've had 10 stents too. Some stents have blocked but some have remained very healthy indeed, around 50-50. Bypass surgery is traumatic without a doubt and the anxiety before surgery is terrible. So, down to my opinion. If this was my Mother, I would be suggesting Angioplasty (stenting) to the Mid LAD and leave the other vessels alone. I would get her vitamin B12 and Omega-3 supplements and ensure she doesn't smoke and eats healthy. If the Doctors recommend any medications, particularly anticoagulants such as Aspirin, I would ensure my Mother takes them. With such lifestyle changes there is a high chance existing disease will not get any worse. This is just what I would do and is my opinion.