The renal arteries supply blood to the kidneys. They branch from the main artery that carries blood from the heart to the lower body. Before reaching the kidneys, each renal (kidney) artery divides into four or five branches. Kidney (renal) artery disease occurs when blood flow to one or both kidneys is restricted or blocked as a result of atherosclerosis, which is the buildup of plaque in the arteries. When blood flow to the kidneys is restricted or blocked by atherosclerosis in the renal arteries, the kidneys are deprived of the nutrients and oxygen they need to function.

Kidney artery disease is similar to heart (coronary) artery disease: Both are the result of atherosclerosis. You may have heard atherosclerosis referred to as "hardening of the arteries.” During the process of atherosclerosis, arteries become thickened and narrow due to the buildup of plaque on their inside walls, and over time, they lose their flexibility. As a result, the size of the channel through which blood flows becomes smaller and blood flow is restricted.

Smoking, high cholesterol, high blood pressure, diabetes, a high-fat diet, lack of physical activity, obesity, age and a family history of heart disease are factors known to increase your risk of developing atherosclerosis. If you have been diagnosed with narrowing of arteries that supply blood to your heart (coronary artery disease), brain (carotid artery disease) or legs (peripheral artery disease), you are also at increased risk for kidney artery disease.

Risk Factors You May Be Able to Control

• Smoking. It’s time to quit. Talk to your healthcare team about developing a strategy that will work for you. It may include analyzing when you smoke (your triggers), joining a support group and taking medications, among other things. The important thing is that you get help to kick a habit that is most definitely harming your health.
• Diabetes. If you have diabetes you are at greater risk for kidney artery disease and heart disease. Work with your doctor to carefully manage your diabetes. 
• High blood pressure and high cholesterol. Make a point to have your blood pressure and cholesterol checked regularly. 
• Lack of physical exercise. Make time to exercise. It will improve you overall health and help you manage your diabetes, blood pressure and cholesterol. For help starting with physical activity, visit the SecondsCount center on Physical Activity, Exercise & Your Heart.
• Being overweight or obese. Men and women who are overweight are about 20 percent more likely to develop cardiovascular disease. If you are overweight, SecondsCount Heart-Healthy Eating Guidelines are a great way to ease into losing those extra pounds.

Risk Factors You Can't Control But Should Be Aware Of

• Family history of cardiovascular disease. Ask your doctor if your family history puts you at greater risk for kidney artery disease. 
• Age. Atherosclerosis is a process that continues as you age. The older you are, the more time fatty deposits have had an opportunity to build up in your arteries.

Keep in mind that kidney artery disease and coronary, carotid and peripheral artery disease (PAD) all are caused by the process of atherosclerosis. This means that, if you’ve already had a blockage or narrowing of the coronary, carotid or peripheral arteries, then you are at increased risk of having similar problems with the arteries that carry blood to your kidneys. To learn more about minimizing your risk factors for kidney artery disease and other cardiovascular diseases, visit SecondsCount’s center on Risk Factor Modification.