Patient page. Blood pressure control and stroke: an ounce of prevention is worth a pound of cure.

Abstract

A stroke, or brain attack, is caused by the sudden loss of blood flow to the brain or bleeding inside the head. A stroke can result in brain damage that causes disability or even death. By far the most common cause of stroke is high blood pressure, also called hypertension. More information about stroke and the conditions that increase the risk for stroke can be found on the next page. Blood pressure readings of greater than or equal to 140 mm of mercury (mm Hg) for the top number (called the systolic blood pressure) and greater than or equal to 90 mm Hg for the bottom number (called the diastolic blood pressure) indicate high blood pressure or hypertension. If blood pressure remains at this level or higher over years, serious damage is done to the blood vessels of the body. The figure compares a blood vessel damaged by hypertension with a normal healthy blood vessel. When blood vessels are damaged, blood cannot flow freely to vital organs. If blood flow is cut off completely, a brain attack occurs. Small increases in blood pressure can dramatically increase a person’s risk of stroke. In one study, for every 10 mm Hg increase in the systolic blood pressure over normal, the risk of stroke increased by 28%. This means that someone with a systolic blood pressure of 170 mm Hg has an 84% greater chance of having a stroke than someone with a systolic blood pressure …