I was diagnosed with a bicuspid aortic valve at around 27, and with ADD at 50. I credit the Adderal for enabling me to actually make and keep doctors appointments and get the severe stenosis diagnosis before it damaged the rest of my heart.
My primary care physician, cardiologist, and surgeon all agree that I should keep taking the adderal up to the day before surgery, as the benefits outweigh the risks. It does not increase my heart rate at all, and my executive function is greatly enhanced.
I don't have a study handy to reference, but those I found when I looked up the subject agree that it doesn't increase risk much, if at all.
Maybe ask your doctors to reconsider? Non-stimulant add medication are far less effective for adults.