Hypertension, or high blood pressure, is often called a "silent disease" because you usually don't know that you have it. There may be no symptoms or signs. Nonetheless, it damages the body and eventually may cause problems like heart disease.
Renal artery stenosis is a narrowing of arteries that carry blood to one or both of the kidneys. Most often seen in older people with atherosclerosis (hardening of the arteries), renal artery stenosis can worsen over time and often leads to hypertension (high blood pressure) and kidney damage. The body senses less blood reaching the kidneys and misinterprets that as the body having low blood pressure. This signals the release of hormones from the kidney that lead to an increase in blood pressure...
Blood pressure is most often measured with a device known as a sphygmomanometer, which consists of a stethoscope, arm cuff, dial, pump, and valve.
Blood pressure is measured in two ways: systolic and diastolic.
Systolic blood pressure is the maximum pressure during a heartbeat.
Diastolic blood pressure is the lowest pressure between heartbeats.
Blood pressure is measured in millimeters of mercury (mm Hg) and is written systolic over diastolic (for example, 120/80 mm Hg, or "120 over 80"). According to the most recent guidelines, a normal blood pressure is less than 120/80 mm Hg. Hypertension is blood pressure that is greater than 140/90. For people over age 60, high blood pressure is defined as 150/90 or greater. Prehypertension consists of blood pressure that is 120 to 139/80 to 89.
Blood pressure may increase or decrease, depending on your age, heart condition, emotions, activity, and the medications you take. One high reading does not mean you have high blood pressure. It is necessary to measure your blood pressure at different times, while you are resting comfortably for at least five minutes. To make the diagnosis of hypertension, at least three readings that are elevated are usually required.
In addition to measuring your blood pressure, your doctor will ask about your medical history (whether you've had heart problems before), assess your risk factors (whether you smoke, have high cholesterol, diabetes, etc.), and talk about your family history (whether any members of your family have had high blood pressure or heart disease).