92 year old grandmother has blood in her urine she has no pain. could this be caused by her aortic stenosis?

Not likely: Much more likely, as female and 90+, to be a urinary tract infection. She needs seen by her dr or an urgent care for test. It is not uncommon for absence of (noticed) symptoms in the geriatric set.

Blood in urine: The blood in her urine is not likely to be caused by aortic stenosis, even if she were on Coumadin (warfarin) if she had a metal valve. What your grandmother needs is a consultation with a urologist who will probably order a renal ultrasound to assess her kidneys. She may need a urine culture and a cystoscopy if that culture is negative for a urinary tract infection.

Mo: Blood in urine is either a stone, hemoglobinopathy, infection, or tumor.