When plavix is stopped, I don't think it causes an existing stent to block. There is no evidence to suggest there is any benefit for taking plavix for more than a year, and this is the protocol which still stands in the UK. I've had 10 stents and stopped plavix after a year each time, with no stents becoming blocked. There is also a suggestion that plavix does absolutely nothing for women. There are other medical conditions which can mimic heart issues very closely, especially if something is pushing on the vagus nerve.
One of the blood tests they would have performed would have been a troponin test, to see if your cardiac enzymes were elevated. This is taken 12 hours minimum after your pains started. If the results were negative, then your heart muscle is not being damaged.
Did your doctor have you increase your aspirin regiment when you went off Plavix?
What kind of stent do you have? Medicated or non-medicated? My husband had his first heart attack at age 49. He had 4 stents put in. He was on Plavix for a year - then his cardio took him off. 5 months later he had another heart attack. He is doing fine, but they are now telling us that he will probably be on Plavix for the rest of this life. That is fine with us - I would hate to worry about another clot forming. All of his stents are the medicated ones. Good luck to you - and I would certainly ask for another cath so they can see what is going on.