What complications can occur for dogs spayed during heat?

I recently got a dog from a shelter and they required her to be spayed (while in heat) before I took her home. Ever since I picked her up from being spayed (7 days ago) she has had vaginal bleeding (small drops here and there) as if she is still in heat. Is she finishing out her heat cycle that had already started even though she was spayed? Or, is this a sign of a more serious complication or a botched operation. Also, otherwise she appears to be totally healthy, happy, energetic, playfull, hungry, etc. etc. She has another appointment with a vet soon, but I thought that I might get a quick answer here on whether or not I should be concerned. Thanks for your help.

When it got spayed that was the end of the heat. The uterus has been removed. Its not possible to be in heat with no uterus. It could be hormones. I don't think it is a botched surgery. Animals are spayed all the time in heat and pregnant. There really is not any more of a danger to the dog. It takes longer to do the surgery as there are more blood vessels leading to the uterus when she's in heat. I would not be concerned if the dog is otherwise acting normal. I would bring it up to the vet at your next appt.