Calling down with A high in the face of serious aggression is usually just not a valid option to take but in rare instances the facts dictate otherwise. I will post the immediate hand previous to this when I raised with only AK high on the turn against a solid player that had three bet preflop from the BB and took down the pot and showed the hand. The very next hand I get dealt AQo UTG and raise and am called by the table fish (+75% VIP who is pretty aggressive). To run a bluff at limit you need to be able to sell your story according to your table image, action or lack thereof and the cards showing. If you fail to prepare a proper story line your bluff will almost always fail unless the guy you're bluffing has shit. The fact that the fish only called my flop bet on the J44 flop was just not in his nature if he actually caught a piece of it, he would have raised given his past history. So I check the turn to let him bet when another rag falls so I can checkraise him with what I still consider to be the best hand and I am a little amazed that I get three bet but given his flop action and past history it just doesn't add up as there is no way he can three bet me without a hand that ties or beats AJ and if he had that hand I would have heard from him preflop or on the flop so I still believe he is full of shit but I just call and plan on calling a river bet as well. He was a little wacko in general but I believe that my action on the setup hand helped him to error in the following hand.
Remember if you are going to run a bluff make it make sense or you have little chance of pulling it off.

Set Up Hand:

Party Poker 5/10 Hold'em (10 handed)

Preflop: Hero is UTG+1 with , .
1 fold, Hero raises, 7 folds, BB 3-bets, Hero calls.

Flop: (6.40 SB) , , (2 players)
BB bets, Hero calls.

Turn: (4.20 BB) (2 players)
BB bets, Hero raises, BB folds.

Final Pot: 7.20 BB

Results in white below:
No showdown. Hero wins 7.20 BB.


Ace HIgh Call Down:

Party Poker 5/10 Hold'em (10 handed)

Preflop: Hero is UTG with , .
Hero raises, 3 folds, MP2 calls, 5 folds.

Flop: (5.40 SB) , , (2 players)
Hero bets, MP2 calls.

Turn: (3.70 BB) (2 players)
Hero checks, MP2 bets, Hero raises, MP2 3-bets, Hero calls.

River: (9.70 BB) (2 players)
Hero checks, MP2 bets, Hero calls.

Final Pot: 11.70 BB

Results in white below: [color=#FFFFFF]
Hero has Ac Qd (one pair, fours).
MP2 has 6s Ah (one pair, fours).
Outcome: Hero wins 11.70 BB. [/color