Renal artery stenosis

Lesley Dobson / 10 May 2017

Renal artery stenosis is a condition that affects kidneys. We often don’t know we have it unless we are having health checks for other conditions.



Causes of renal artery stenosis

Renal artery stenosis happens when the arteries that deliver blood to your kidneys become narrowed. Atherosclerosis is the most common culprit behind this health problem. Atherosclerosis is the medical term used when deposits of cholesterol and fatty substances that are carried in your blood, attach to the inner linings of your arteries. The deposits of this fatty material are called atheroma or plaques.

Learn more about atherosclerosis and high blood pressure

These patches of atheroma can build up and cause your arteries to narrow, harden, and become less flexible. When this happens it is known as atherosclerosis. The narrowing of your arteries affects the amount of blood that can flow through them.

Another, less common cause of renal artery stenosis is fibromuscular dysplasia. This happens when the muscle in the wall of the artery grows in an erratic way. This can cause narrowing of the artery in parts of the artery wall. This can mean that not enough blood reaches the kidneys, and over time they become damaged. This usually affects younger people and women.

Because your arteries have become narrower, this reduces the amount of blood-carrying oxygen that reaches your kidneys. This is important because your kidneys need enough blood to carry out their vital functions. These include helping to control your blood pressure, helping in the process of making your red blood cells, and making a type of vitamin D that is important in helping to keep our bones strong.

Your kidneys’ reaction to reduced blood flow is to take this as a message that you have low blood pressure. They react to this by sending a message to your body (by excreting hormones) to retain more water and salt. The result of this reaction is that your blood pressure goes up.

When atheroma slows down the blood flow to our kidneys, this can cause serious health problems over time, including renal artery stenosis.

Learn more about causes of high blood pressure

Reduced blood flow to the kidney due to atherosclerosis

Other names for renal artery stenosis

Renal artery stenosis is known by a number of alternative names, including Stenosis – renal artery; Renal hypertension; Hypertension – renovascular; High blood pressure – renovascular, and Renal artery occlusion.

Risk factors for renal artery stenosis

  • being older – 60 to 70 years of age - is a clear risk factor for developing renal artery stenosis. And once you are over 70 your chances of developing this condition increase.
  • having high blood pressure – 140 over 90mmHg, or above - can put you at greater risk of developing renal artery stenosis.
  • kidney problems
  • cardiovascular disease
  • cerebrovascular disease, such as stroke, TIA - transient ischaemic attack (similar to a minor stroke)
  • hyperlipidaemia (high cholesterol or triglyceride levels in your blood)
  • having high cholesterol
  • diabetes
  • smoking
  • having a diet that includes too much fat
  • having a history of cardiovascular or kidney disease in your family
  • coming from a white ethnic background

Symptoms of renal artery stenosis

Renal artery stenosis can be hard to diagnose, as it doesn’t usually produce symptoms that make it easy to identify, until you have had it for some time, and it has become more serious. However, there are some situations where another health problem can lead doctors to a diagnosis of this condition.

Doctors can discover that a patient has renal artery stenosis when they investigate cases of high blood pressure (also known as hypertension). The high blood pressure may have come on suddenly, may be very severe, may appear in someone with no family history of the condition, and may be difficult to treat using the usual high blood pressure medications.

This condition may also be discovered when doctors are treating other conditions connected to the kidneys and heart.

If doctors suspect that you may have renal artery stenosis, there are a number of tests they can carry out. These include using a stethoscope to listen to the blood flowing along the artery to your kidneys. Particular sounds can indicate that the artery has become narrower (usually due to atherosclerosis).

Your doctor may carry out tests, looking at your blood and urine, to check for further signs that your kidneys have been affected. They may also use a computerized tomography (CT ) scan and magnetic resonance angiography (MRA) to check on the arteries supplying blood to your kidneys.

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Treatments for renal artery stenosis

Once you have been diagnosed with renal artery stenosis, you doctor will discuss the treatment you need to help control your blood pressure. This is likely to include taking medicines to help bring your blood pressure down.

Keeping a close check on your blood pressure is really important in the management of renal artery stenosis. You may be prescribed aspirin, and other drugs that may help to reduce the effects of atherosclerosis.

Your medical team may decide to carry out an angioplasty to widen the narrowed area in your affected artery, and allow better blood flow to your kidney.

To do this they would attach a very small balloon to the end of a narrow tube, insert this into the affected artery, and move it along the artery to the affected section. Once in place, they would inflate the balloon to open the artery up, to allow more space for blood to flow through. They may also insert a stent, a small wire tube, into the artery, to help keep it open.

Another possible treatment for renal artery stenosis includes a renal artery bypass, where your doctor attaches part of a blood vessel from elsewhere in your body, to your renal artery, creating a bypass.

Your doctor will talk to you about the best treatment for renal artery stenosis in your case..

Lifestyle changes for renal artery stenosis

Smoking is bad for your health in a number of different ways, and can increase your blood pressure. So if you smoke, your medical team are very likely to say your need to quit.

There is plenty of help available to help you give up smoking. Look online to see what’s available locally, and ask at your doctor’s surgery or pharmacy about stop smoking programmes. You can also look online, at Smokefree NHS,  www.nhs.uk/smokefree which offers different types of support to help you stop smoking.

Bringing your blood pressure down is another important element in improving your health when you have renal artery stenosis. There are steps that you can take to help reduce your blood pressure, if it is at a level where it is a problem. Watch your weight – if you are overweight, try to lose enough to bring yourself down to a healthy weight. This will benefit your health overall, and should help to bring down your blood pressure.

10 lifestyle changes to help reduce high blood pressure

Take a look at your diet, and see where you can make healthy changes. Add fruit and vegetables to your menu, to make sure that you are eating at least five portions a day (more, if possible).

You can have a couple of pieces of fruit – or vegetables if you prefer – between meals, juice or fruit with cereal for breakfast, a mixed salad for lunch, and couple of portions of vegetables with your dinner. Make a plan and you should be able to manage five portions a day without too much trouble.

If you’re used to adding salt to food while you’re cooking, and at the table, try to cut right back. Salt is known to increase blood pressure.

10 signs you’re eating too much salt

Exercise is a good way of improving your health, and reducing your blood pressure. However, you do have to tailor the amount you do, to your own personal circumstances. If you have renal artery stenosis or other health conditions, you should talk to your GP about whether it is a good idea for you to have some exercise, and what type of exercise would be best for you.

Walking and swimming might suit your level of fitness and be a good way to get started (as long as you don’t overdo it). If you have long-term health problems, stretching and bending exercises carried out at home, maybe while sitting in a chair, may be more suitable. Ask your medical team if a physiotherapist can visit and give you advice about suitable exercises.

You can also find advice on ‘Getting active’, on the British Heart Foundation’s website.

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