Hello and thank you for using HCM. I carefully read your question and i totally understand your concern.
It is very difficult to give an opinion just by this short story. But I will try to explain you something.
It is quite known in cardiology that stent ri-stenosis might happen. This risk is higher during the first 6 month and than decreases. But there are other possibilities after a stent re-stenosis like
angioplasty whith balloon , stent-intra
stent implantation that mean that you might implant a stent into the obstructed stent, always depending on the type of your first stent and the characteristic of the stenosis. And the last option when the other are not possible is by-pass surgery that you all ready know. So, yes...if your three arteries have problems and your stents get stenosis you might end to
bypass surgery.
If this is technically possible or not depends on the characteristics of your coronary arteries and the positions of stenosis.
The risk of bypass surgery depends on your age, your heart function and other organs functions.
But you should not worry. You do have possibilities to go quite well.
There are a lot of possibilities today with a good chronic medical treatment, angioplasty and by pas surgery.
Wish I was helpful. Best regards.