Hi! Not sure if this helps, but I applied for medical biosciences at imperial with 10 A*'s at GCSE and A*AA achieved at A Level. I was rejected. I also applied the previous year to both UCL and Imperial with predicted 3 A*'s in bio, maths and chem for biochem, I received an offer from Oxford and UCL, however I was also rejected from Imperial. Obviously there is more to your application than just grades. In particular, one thing I was advised by Imperial tutors was to include lots of evidence of team work in my personal statement, due to their style of group reliant teaching. I chose not to listen to this advice. Potentially if I had adhered to it I may have had a better chance at receiving an offer.
Additionally, there were several students this year with A*AA at both UCL and Imperial who received an offer for biomedical sciences. Another thing you might consider is asking your teachers to boost one or two of your predictions. It's always worth a try. For example, my friend went from AAB to A*A*A predictions after asking for an increase. Best of luck! Try not to think about predicted grades too much, instead focus on your personal statement. Students often exceed their predictions on results day, so you should expect a brilliant set if you put in the hard work!