Some times when a blood vessel narrows slowly over time (weeks to months, for example), the body develops tiny vessels from affected neighboring vessels to help out -- theses vessels are called collaterals. I believe your doctor was referring to the fact that your body has had time to developed collaterals, therefore it might not be necessary to open up an occluded stent. Of course some times collaterals are present but inadequate, especially during exertion. I recommend getting a copy of the catheterization images and obtaining a second opinion with another cardiologist. Good Luck!
I have had multiple stents inserted. Sometimes they close up. Sometimes I get lucky and it can be easily rectified without having to place another stent in place. It's extremely important to take your meds and follow the instructions from your doctor on a healthy diet and exercise. Heart disease will be degenerative if you don't follow treatment completely. Right now, I'm 50 and can't load my dishwasher without taking a break in the middle to allow my heart to calm down and catch my breath. I'm med resistant. Any time you start having pain that is indicative of a heart incident, go directly to the ER.