Renal Artery Disease
Like other peripheral artery diseases, renal artery disease is caused by
the buildup of plaque in the arteries that lead to the kidneys. Plaque
is made up of fats and cholesterol, and as it accumulates in the renal
arteries, it causes the arteries to stiffen and narrow, which blocks the
flow of blood to the kidneys. Obstructions (blockages) in the renal arteries,
known as renal artery stenosis, can cause poorly controlled high blood
pressure, congestive heart failure, and kidney failure.
Renal artery disease most often is related to peripheral artery disease
(atherosclerosis in arteries outside the heart) or coronary artery disease.
Atherosclerotic renal artery disease is the most common form of this condition,
accounting for more than 80 percent of all renal artery disease. The balance
is generally caused by fibromuscular dysplasia, a congenital disorder
that causes thickening of the artery walls without plaque build-up.
The kidneys play an important role in regulating blood pressure by secreting
a hormone called renin. If the renal arteries are narrowed or blocked,
the kidneys cannot work effectively to control blood pressure. Persistent
or severe high blood pressure is a common symptom of renal artery stenosis.
High blood pressure that is not controlled by medications and lifestyle
changes, including diet and exercise, may be a symptom of renal artery
disease. Symptoms of renal artery disease may also include episodes of
fluid retention or congestive heart failure. In some cases, renal artery
disease may be entirely asymptomatic (not associated with any symptoms).
In severe cases, renal artery disease may lead to kidney failure. Symptoms
of kidney failure include weakness, shortness of breath and fatigue.
Many of the risk factors for renal artery disease are the same as those
for atherosclerosis in other parts of the body, such as coronary artery
disease and peripheral arterial disease. Risk factors for renal artery
- age over 50
- high cholesterol
- high blood pressure
- family history of coronary artery disease
- family history of peripheral arterial disease
- family history of renal artery disease
Renal Artery Ultrasound
A renal artery ultrasound evaluates blood flow to the kidneys through the
renal artery and is often used to diagnose renal artery stenosis. 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.
Untreated renal artery disease gets progressively worse and can lead to
kidney failure. Like treatment for heart disease, there are many treatments
available for renal artery disease. The right treatment for an individual
depends on the severity of the disease and the individual’s medical history.
All patients with renal artery disease require treatment for cardiovascular
risk factors (such as high blood pressure, high cholesterol, diabetes)
and lifestyle changes such as weight reduction, smoking cessation, exercise
and a low-salt and low-fat diet. Medication to lower blood pressure is
an important part of treatment, along with careful monitoring of the response
to the blood pressure medications to be sure the blood pressure is lowered
to the treatment goal. Regular follow-up every 4 to 6 months will be part
of the treatment plan so your physician can monitor your condition.
For some patients with significant narrowing of the renal arteries, particularly
patients with narrowed areas in the renal arteries on both sides of the
body, or those with severe symptoms, a procedure may be recommended to
open up the blocked arteries to restore circulation. In some cases, opening
the blocked arteries may improve kidney function and may improve control
of high blood pressure. Not surprisingly, the techniques used to open
blocked renal arteries are very similar to those used to treat blocked
A small catheter – a long, thin tube – carrying a tiny balloon
is inserted through a small puncture in the groin and guided by X-ray
to the kidney artery. When the catheter is guided to the narrowed part
of the artery, the balloon is inflated. As it expands, it compresses the
plaque against the artery walls, re-opening the vessel for blood to flow
through. Once the artery is open, the physician may insert a stent at
the site to keep the artery open and support the arterial wall.
With the development of new and improved types of stents, angioplasty with
stenting is the preferred treatment for renal artery disease. But, in
certain cases, surgical treatment may be necessary to restore blood flow
to the kidney and preserve kidney function.