Nine years ago i had a "Minimally Invasive Mitral Valve repair". I awoke from the anesthetic with a migraine aura.
In the weeks following I was experiencing up to five attacks a day! The good news was they were "Silent" migraines. No debilitating pain but still the nausea, sensitivity to lights and visual disturbances for thirty minutes that precluded driving and the low intensity post migraine headache. Over about six months the frequency lessened, to one daily then a few a week and then settled down to one or two a week. Standard triggers- low blood sugar/hangover/stress etc.