"My concern in your case is that you are young and developing Cardiac Artery Disease"
I'm only 48 and my RCA is like a string of sausages, my LAD was choked and my circumflex had to be stented. I don't think age is an issue anymore.
I have, or did had two small arteries with blockages too small to stent. It was the opinion of my Cardiologist that in both cases I probably had some collateral arteries (very small vessels that enlarge to help out the area) forming, and we agreed to just let the small arteries plug up, the collateral arteries would take over. The Angina I was experiencing stopped so I assume that is exactly what happened, or the increased drug doses that I started after getting my pacemaker are handling the issue. I'll probably have another stress test in a few months and get an idea of what happened.
My concern in your case is that you are young and developing Cardiac Artery Disease. Are you taking statin drugs to control the problem, and hopefully you following a heart-healthy diet, exercising and don't smoke and don't have diabetes. I'd suggest that you are fortunate to have a small vessel involved with CAD, but believe me, it is a indication that you have to be very careful. I've got eight stents and have had heart attacks, and wish I would have been more proactive when younger.
I'd take this situation very seriously and listen to your Cardiologist and also monitor boards like this. Keep us informed.
My cardiologist old me that the standard for a stent for 70% or over unless you refuse it.
The problem is that the plaque can rupture at any time at this size and it becomes a life threatening risk. If the plaque ruptures, you can suffer a clot in a Coronary artery or the brain. If the artery is too small to be treated, or too difficult in location, then they may
opt to treat you with medication to lower the risk of clotting. Aspirin is the favourite but maybe they will prescribe something a bit stronger.
Usually when you start having any symptoms such as pain, is when they opt to put in a stent.