High blood pressure can affect many parts of the body besides the heart.
Brain: Very high pressure can cause a break in a weakened blood vessel, which then bleeds into the brain. This can result in a stroke. If a blood clot blocks one of the narrowed arteries, it can also cause a stroke.
Eyes: High blood pressure can eventually cause blood vessels in the eye to burst or bleed. Vision may become blurred or otherwise impaired, or be lost entirely.
Kidneys: The kidneys act as filters to rid the body of wastes. Over time, high blood pressure can narrow and thicken the blood vessels of the kidneys. The kidneys filter less fluid, and waste builds up in the blood. The kidneys may fail altogether. When this happens, medical treatment (dialysis) or a kidney transplant may be needed.
Arteries: As people get older, arteries throughout the body "harden," especially those in the heart, brain, and kidneys. High blood pressure is associated with these stiffer arteries (atherosclerosis). This, in turn, strains the heart and kidneys.
Heart: High blood pressure is a major risk factor for a heart attack. The arteries bring oxygen-carrying blood to the heart muscle. If the heart cannot get enough oxygen, chest pain, also known as "angina," can occur. If the flow of blood is blocked, a heart attack results. High blood pressure is also the number one risk factor for congestive heart failure.