Maybe I misunderstood, but what she says the vet described is CT. It is when the membrane lying over the C-ring of the trachea collapses down, causing constriction of the airway.
01 Tracheal Collapse - VeterinaryPartner.com - a VIN company! My vet x-rays immediately for this; however, x-ray does not reliably diagnose. Fluoroscopy is the best diagnostic but is done at a University Hospital usually. My Cricket had CT. It did not progress until she got elderly. She then developed congestive heart failure, which can happen w CT dogs.
You're right, when my Cricket developed congestive heart failure, it did have a similar honk.
You should watch the gums if there is another episode. If the gums turn bluish, that is a medical emergency and you need immediate vet care. That means she is not getting enough oxygen due to the membrane collapse.
It was nice to see a poster care enough to take their dog to the vet, especially after all of the threads where ppl just blow off symptoms and ppl's advice to take to vet.
I agree, this should continue to be followed closely by your vet.