Can an untreated bleeding stomach ulcer that perforated the stomach lead to an aortic thrombus?

No: Aortic wall is thick enough to withstand the acid from perforated ulcer. There will be a lot of symptoms from perforated ulcer before it would affect the aorta, if ever. For good health - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Drink enough water daily, so that your urine is mostly colorless. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Practice safe sex.