I should start by saying that I have a degree in integrative medicine, and firmly believe that Western and Chinese medicine can be intelligently combined to work best for the patient.
One of the difficult things about discussing Chinese medicine online is its inherent differences from western medicine. To accurately diagnose you from a Chinese perspective I would have to have a complete picture of your mother's overall health status and be able to see her tongue and take her pulse. Which means that - to be responsible to her as a patient first - I will be recommending you see a reliable practitioner to have a full Chinese evaluation. That practitioner will then be able to safely recommend a course of herbal formulas and/or acupuncture.
From a western perspective I have insufficient information to comment on your mother's health. One thing I can say is that I have noticed in my own practice that patients tend to downplay the seriousness of a disease if the disease is common and "everyone has it." However, from a medical point of view, sometimes the most common things are the most serious. Arteriosclerosis is very serious, and is responsible for many deaths in this country. In that sense, it can't be ta***** *****ghtly. If your mother doesn't like to take her medications, she should discuss this with her physician. Under no circumstances should she take medications intermittently or differently than prescribed. However, a good physician will help her limit her prescriptions to those she really needs, and be willing to work with her to find the minimal doses necessary. If she doesn't like her physician for whatever reason, or doesn't feel she is being heard, she should ask around and try to find someone who will work with her towards these goals.
If they are recommending stents, there is a concern that her blood flow is insufficient. Most likely the concern is her brain or heart - either of which could be seriously compromised without sufficient blood flow, but it might be another location as well. You didn't say where the stents would be located, or if the previous stents themselves failed and are being replaced, or if she needs more because they would be going into different locations. Regardless, it is very important to understand the physician's thinking, and why these recommendations are being made. I urge you to get the answers you need from the him/her, or find a new physician and get a second opinion.
You say she is eating a healthy diet... but that could mean many things in today's world! Hopefully she is following a low-cholesterol diet, consuming very little sugar, very little foods with processed grains - especially wheat, getting the majority of her calories from fruits and vegetables and whole grains, and completely avoiding dairy products. And, from a Chinese point of view, she should be limiting her intake of raw or cold foods. Vegetables should always be at least lightly cooked, and fruit should be eaten at room temperature. Ditto for leftovers or anything right out of the fridge - it should be left on the counter until it is at least room temperature, or if appropriate, re-warmed. Whenever there are heart conditions we also always recommend a lot of darker greens, such as spinach, kale, collard, beet tops, etc.
It is possible that Chinese medicine, particularly herbal formulas, could help your mother. The specific formula would depend on her Chinese diagnosis, which would be unique to her and her symptoms, and address her overall health as well as her arteriosclerosis. An acupuncturist / herbalist will sit down with your mom, talk to her at length about her symptoms, her history, and her general health including emotional well-being, look at her tongue, take her pulse and then develop a diagnosis.
Although from a western perspective atherosclerosis is always just atherosclerosis, Chinese practitioners will classify the disease more finely, based on the specific constellation of symptoms.
Chinese diagnoses may sound very odd but they mean something very specific to the Chinese practitioner, just as the word "arteriosclerosis" does to a western physician. Potential diagnoses for arteriosclerosis might be things like: heart qi vacuity, phlegm turbidity, chest yang impediment, or several others. Each diagnosis requires a specific herbal formula, so getting the right diagnosis from a practitioner is very important since the wrong formula can do more harm than good. Once you have the right formula, results can be very positive.
A conscientious practitioner will also discuss with you the medications you are currently on, and make sure there will be no negative interactions with herbal formulas. Depending on the severity of your symptoms you may not be able to completely stop taking western medications, but you may be able to augment with herbs and thereby take less of your western meds. In milder cases you may indeed be able to rely on herbs alone.
Lastly, with respect to acupuncture, while regular acupuncture treatments will help your mom's overall well-being and help keep her active and feeling good (and help mitigate any side effects of her medications, if that's the reason she doesn't like taking them), it won't be able to address the main health issues; herbal formulas are what can help with that.
When you look for an acupuncturist or herbalist in your town, make sure that they have at least a Master's degree in Oriental Medicine, which is a four year degree. Individuals can do acupuncture with only two years of school and will not have the knowledge to develop a formula to suit your mother's more complex needs. However (depending on the state you live in) both levels of education might be given the title "licensed acupuncturist," it will be up to you to inquire regarding the actual level of education.
I hope this has addressed the main point of your question. And I hope you understand why I haven't recommend specific herbs - without more details, and without seeing your mother's tongue and taking her pulse, I could accidentally recommend the wrong thing, potentially making her symptoms worse. And I definitely don't want to do that!
BTW, it is GREAT that your mom is so active! Congratulations to her on that.
Here's wishing the both of you the best in health,