I agree that if any of the air passages are blocked it would cause a hard draw. I also appreciate that you provided a photo so that captainbrianbeard could see the plastic ring that I was reffering to and that it is the last point of entry for the air to enter the atty. You can also see that the ring is very close to the coil. When the coil gets to hot, it melts and closes up.
His question was "if the atty gets too hot can it close up the metal air holes." The correct answer is no, it can not close up the metal air holes, but, it can close up the plastic ring and cut off the air causing a hard draw.