Had any surgical prep taken place? Usually to discontinue the procedure, (and bill with a -73), physician needs to be just about ready to go....line placed, sedation administered etc.
I am not an ASC expert, but do know that providers can bill an E&M in the ASC setting if it's medically necessary. In this case, as long as the documentation meets the proposed LOS, and there's no other surgical procedure taking place, then I don't see why you can't. After all, he did the patient evaluation to determine that the procedure could not be done, and since the surgery didn't take place, you don't bump up against global days.
What I'm not sure about is whether or not you can bill an E&M if the provider owns the ASC. That would require someone's opinion other than mine.