Renal hypertension, which health experts more commonly refer to as renovascular hypertension, is a type of high blood pressure that starts in the kidneys. It occurs due to a blockage in the arteries that carry blood to the kidneys.

Without treatment, the increase in blood pressure can cause kidney damage and other complications.

This article discusses what renovascular hypertension is. It also examines how high blood pressure affects the kidneys, and outlines the causes, symptoms, and treatment options for the condition.

A person holding a model of the kidneys.Share on Pinterest
pepifoto/Getty Images

Renovascular hypertension occurs when the blood vessels in the kidneys have become narrowed or blocked. Usually, this happens due to a blockage in the renal arteries, which are the arteries that supply a large portion of the blood to the kidneys.

Renovascular hypertension is one of the most common causes of secondary hypertension, which is high blood pressure that stems from a different medical condition. Moreover, it can lead to high blood pressure that is resistant to treatment.

What is high blood pressure, and how does it affect the kidneys?

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) defines blood pressure as an increase in the amount of force that blood puts on the vessels as it moves throughout the body.

Over time, blood pressure can damage and weaken blood vessels throughout the body, including those in the kidneys. When the blood vessels in the kidneys become damaged, it can affect how well the kidneys function.

When the kidneys do not function properly, it can lead to excess fluid and waste buildup in the bloodstream. This in turn can cause high blood pressure, resulting in further damage to the kidneys.

Over time, a person can develop kidney failure.

The NIDDK notes that in most cases, an individual with high blood pressure will not have any symptoms. Sometimes, however, a person may experience unexplained headaches.

Similarly, early stages of kidney disease or damage may not cause any symptoms. However, as kidney damage progresses, a person may develop edema. This is swelling that can occur in various parts of the body, including the feet and hands.

If kidney disease progresses to an advanced stage, an individual may develop symptoms such as:

If a person is taking multiple medications to manage their blood pressure, and these are not having an effect, doctors may suspect that renovascular hypertension could be the cause.

Any condition that affects blood flow to the kidneys can lead to renovascular hypertension.

The most common causes of renovascular hypertension are forms of renal artery stenosis. Atherosclerosis, which is the buildup of plaque in the arteries, is behind 90% of cases. Fibromuscular dysplasia, which is a condition that causes the narrowing of the arteries, is behind 9% of cases.

Other potential causes include:

  • inflammation of the arteries that can be due to the following conditions:
  • radiation fibrosis, which is a side effect of radiation therapy
  • compression of the renal arteries
  • renal artery dissection, which can occur after injury to the blood vessel
  • obstruction resulting from surgery on the arteries

Is it hereditary?

Research indicates that people with close relatives who have developed renovascular hypertension are more likely to develop it than those without a family history of the condition. The likely cause is a genetic variation or mutation.

Other research suggests that genes may play a role in the development of kidney disease due to hypertension. The scientists note that understanding the variants may help lead to better targeted treatments in the future.

Diet can play a role in helping increase or decrease a person’s risk of developing renovascular hypertension.

The National Kidney Foundation recommends a person follow Dietary Approaches to Stop Hypertension, or the DASH diet, to help improve their hypertension.

The DASH diet recommends foods such as:

It also limits or eliminates the consumption of:

The main goal of treatment for renovascular hypertension is to lower blood pressure. Lowering blood pressure can help prevent kidney damage and have a positive effect on other aspects of health.

Medications

Individuals with renovascular hypertension will typically require multiple medications to treat the condition.

According to NIDDK, there are two types of blood pressure medication that may help with slowing the spread of kidney disease. These are angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs).

In addition to these, a doctor may prescribe other medication to help with either the kidneys or high blood pressure. One type of medication a healthcare professional may prescribe is diuretics, which help the kidneys process and remove more fluid.

Surgery

To directly treat renal artery disease, a doctor may recommend undergoing one of two different procedures: angioplasty or renal bypass surgery.

Angioplasty involves using a balloon inserted through the groin to help widen the arteries in the kidneys that have closed or narrowed.

Renal bypass surgery involves placing stents to bypass the blocked arteries.

Both are low-risk procedures, and a person can have either of them as an outpatient or inpatient. An inpatient surgery will require an individual to spend a single night in the hospital.

Medicines vs. surgery

Medications and lifestyle changes are generally the first line of treatment. Recent research does not suggest that surgery is more beneficial than medications.

A doctor may recommend a procedure such as placing stents to improve blood flow if medications, diet, and exercise are not helping improve renovascular hypertension.

Doctors may also consider surgery if a person is experiencing:

  • progressive worsening of kidney function
  • acute heart failure
  • recurrent acute pulmonary edema
  • a need for a rapid increase in medication for previously controlled high blood pressure

In addition to medications and possible procedures, there are some steps a person can take to help prevent or reduce their high blood pressure.

Some potential changes a person can make include:

Early diagnosis can make a difference in controlling blood pressure and preventing damage to the kidneys.

To diagnose high blood pressure, a healthcare professional will use a pressure cuff to measure a person’s blood pressure. They may diagnose high blood pressure if the blood pressure reading is above 130/80.

To help diagnose kidney disease, a healthcare professional may perform a blood test to check the function of the kidneys. They may also order urine tests to check for albumin, which is a protein present in the urine as a result of damage to the kidneys.

A doctor can use imaging tests to help determine whether a person’s renal arteries have become affected.

Tests they may use to help diagnose renovascular hypertension include:

Renovascular hypertension can lead to several serious complications, such as:

  • stroke
  • heart attack
  • heart failure
  • aneurysm
  • left ventricular hypertrophy, which is the thickening of the left pumping chamber of the heart
  • pulmonary edema, which is excess fluid in the lungs
  • retinopathy, which is a condition that affects the retina
  • vascular dementia, which is a type of dementia that results from reduced blood flow to the brain

High blood pressure, regardless of the cause, can lead to kidney disease or failure. The NIDDK explains that this is because high blood pressure can put additional strain on the kidneys, which can cause them to work inefficiently.

When the kidneys start to work less effectively, it can cause higher blood pressure, which, over time, can damage the kidneys and lead to their eventual failure.

If a person receives a renovascular hypertension diagnosis, it is important that they follow the doctor’s treatment recommendations. This can include making changes to their diet, as well as getting more exercise and taking medications as prescribed. This can help slow the progression of kidney disease.

When left untreated or not sufficiently treated, the condition can lead to kidney failure, which is life threatening and can decrease a person’s quality of life.

A large part of treatment of renovascular hypertension is preventing damage or more damage to the kidneys from occurring.

An individual can change their lifestyle to help prevent high blood pressure. Some steps to try include:

  • avoiding smoking
  • exercising regularly
  • managing stress levels
  • eating a balanced diet low in salt and saturated fat
  • reaching or maintaining a moderate body weight

Renovascular hypertension may not cause symptoms. A doctor may discover a person has high blood pressure during a routine examination.

A person living with high blood pressure who notices their numbers increasing should consult a doctor.

Moreover, individuals living with renovascular hypertension should let a doctor know if they experience any new or worsening symptoms.

Renovascular hypertension occurs when arteries in the kidneys become blocked or narrowed, causing high blood pressure to occur.

Without treatment, high blood pressure can lead to several complications, including kidney failure.

Treatment typically involves the use of blood pressure-lowering medications, diuretics, and lifestyle changes, such as getting more exercise and following a balanced diet.