Renal artery stenosis is a disease of narrowing of the arteries that carry blood to the kidneys. These arteries are known as renal arteries and are responsible for supplying the kidneys with oxygen-rich blood. The oxygen-rich blood helps the kidneys to filter waste and excess fluid from the body. When the renal arteries narrow, the oxygen–rich blood flow to the kidneys is reduced therefore limiting the functions of the kidneys and can eventually lead to increased high blood pressure, kidney damage and edema.
Causes of Renal Artery Stenosis
There are two main causes of renal artery stenosis:
- Atherosclerosis: This is the build-up of cholesterol and fatty substances in the walls of the renal arteries. This narrows the arteries and reduces the overall blood flow. Atherosclerosis is the most common cause of renal artery stenosis.
- Fibromuscular dysplasia: This occurs when the muscles that are outside of the arteries grow abnormally and push on the arteries causing them to become narrow and reduce blood supply to the kidneys. The condition may be congenital (present at birth) and it is also more common in women.
Risk factors for renal artery stenosis include diabetes, obesity, high cholesterol, smoking, sedentary lifestyle, family history of heart disease and diet that is high in sugar, sodium and fat.
Symptoms of Renal Artery Stenosis
Renal artery stenosis does not present any symptoms until it is in its advanced stages. This disease may be discovered during testing for something else. Your physician may suspect you have the condition if you have:
- Hypertension that starts before the age of 30 or after 50
- Hypertension that begins suddenly or tends to worsen without any explanation
As the condition progresses, it may present the following symptoms:
- Reduction in the kidney function
- Fluid retention
- Edema in the body tissues especially the ankles and feet
- Continued hypertension despite trying to lower it with medication
- An increase of protein in the urine
Decreased blood flow through the renal arteries can lead to hypertension as well as edema which tends to worsen as the condition progresses. Flash pulmonary edema can also occur which is when fluids build up in the lungs.
Renal artery stenosis can over time also damage the kidneys and lead to kidney failure.
Diagnosis of Renal Artery Stenosis
Once your physician suspects that you may have renal artery stenosis, he/she will perform a physical examination and look at your medical records for possible risk factors. The following tests will also be ordered:
- Urine test to measure the overall kidney function and proteins
- Blood test to measure the blood pressure regulating hormones and kidney function
- Renal arteriography to check for any blockages in the renal arteries. This involves injecting a special dye into the renal arteries so it shows up on x-rays
- Magnetic Resonance Angiography to provide 3-D imaging of the area being examined
- CT scan
Treatment of Renal Artery Stenosis
Treatment for renal artery stenosis usually depends on the individual’s medical history and the severity of the condition. It includes lifestyle changes, medication and procedures.
- Lifestyle changes can help in controlling blood pressure if it is moderately or severely elevated. This includes eating healthy foods, limiting salt intake and regular physical activities.
- Medications: Medications for lowering high blood pressure is an important part of the treatment. The medications include:
- Calcium channel blockers
- Angiotensin II receptor blockers
- Angiotensin converting enzyme inhibitors
- Alpha-beta-blockers and beta-blockers to help decrease the renal artery dilation
- Diuretics to help reduce fluid retention and swelling
- Procedures: Sometimes lifestyle changes and medication are not enough for treating renal artery stenosis as the condition progresses, which may lead to the kidney being damaged. There are certain procedures that may be recommended by your doctor to help improve the arterial function such as renal stenting and renal artery bypass surgery.
At King’s College Hospital Dubai, we focus on offering an exemplary service. From initial consultation through to final diagnosis, treatment and beyond. Our multidisciplinary team of expert doctors, nurses, cardiologists and technologists are here to offer tailored management and treatment of your condition, and to answer any questions that you may have throughout your time with us. Whatever you need us for, we’re only a phone-call away.