My Father, Who Is 82 Yrs Old, Recently Had A

My father, who is 82 yrs old, recently had a TAVI heart operation to repair the Aortic valve. Prior to the operation he did have some mild memory loss, however since the operation & the general anaesthetic, he seems to get confused and has difficulty remembering things. Could the operation have exacerbated his problems & could this be the onset of dementia?
Many thanks
Diane