You didn't offer any proof that stents work. I said previously they have been shown to work in emergency situations, but I can't find any scientific studies that show they work better than medical therapy in non-emergency cases. Can you provide any references to scientific studies that show stents either prevent future heart attacks or prolong life?I don't think most cardiologists think that diet is not important. Clearly reducing various fatty components in the blood appear to be a good thing in statistically reducing the chance of plaque build up. Diet does help but may be inadequate and may not be followed by everyone. So drugs to reduce cholesterol are used and have been shown to be helpful in large prospective trials.
Angina is not necessary a requirement for a decision on dealing with coronary artery disease.
The first symptom can be death. One can look in the medical literature and cherry pick whatever you want to find. I am a physician but not a cardiologist but an 80% blockage sounds pretty worrisome. Stenting is generally done by interventional cardiologists bypass by cardiac surgeons.
There are various criteria to decide on stenting vs bypass. If the area can be stented that probably is easier and safer than bypass. The only issue with placing a stent and a valve is that for a mechanical valve you need to be on warfarin. For a stent you need to be on an anti platelet agent such as Plavix for at least a year. So one would be on both agents for a year if the valve and stent were done together. Why don't you bring in your literature that suggests that stenting is only required if you are symptomatic to a cardiologist to review with you. I have patients bring things to me which often are fourth rate in quality. Be careful of DR. GOOGLE. Also don't assume that every physician is stupid or a crook.