Hi
Can't help you with the regulatory side but although you don't say why you had the stress ECG it may be worth considering what happened after and why
Not sure your cardiologist was particularly observant - the ECG was abnormal and this meant there was a risk of lack of blood to part of your heart which results in a heart attack or worse. If he had missed it he would have been a bit of a @@@@@@
The stent jumps the narrowing to restore blood flow distal or downstream to the narrowing
So far so good
The problem is the stent can block so the problem recurs. You have a problem with the blood supply to your heart and there is thus a risk of a heart attack - hopefully less than before the stent but this is why the regulator is cautious
Cardiologists basically manage damaged valves, arrhythmias and these blood supply problems. Not much else goes wrong in adults. So while your cardiologist is happy with 'everything else' it means the valves, rhythms and other blood vessels are OK.
Bottom line - your problem was picked up before it did any harm and you may well to live to be 100 but you do have coronary artery disease and so your risk has not returned to that of someone without disease. Your fellow pilots may have the same problem but be undiagnosed and at similar risk but sadly that doesn't stop the regulator putting you under the microscope