I'm sorry you are in such a difficult place. The only surgery I've had since dx is a knee repaired. No problems, at all. It doesn't compare to a by-pass though.

Maybe your medical history causes the docs concern. I certainly wouldn't put off the surgery. Maybe a second opinion will help. Most insurances allow for one.

Sorry my advice is not exact. I just want you to know you are not alone. I'm sending healing hugs your way.