The Heart & Vascular Center offers advanced diagnosis and treatment for renal artery stenosis and renal artery aneurysm. Our surgeons are committed to the best treatment methods, high success in surgical outcomes and leading vascular research.
Understanding Renal Artery Stenosis
The renal artery provides blood flow to the kidneys. When this artery is blocked, it may cause kidney failure and high blood pressure. The kidneys are responsible for removing wastes from the body, regulating electrolyte balance and blood pressure, and stimulating red blood cell production.
A partial blockage of the artery is called renal artery stenosis and may be caused by atherosclerosis (build-up of plaque, which is a fatty material), or other conditions, such as fibromuscular dysplasia (a condition that weakens the walls of medium-sized arteries and occurs in young women). Atherosclerosis causes 80-90 percent of renal artery stenosis. Smoking, obesity, advanced age, high cholesterol, and diabetes are factors which may increase the chance of developing atherosclerosis.
Symptoms of renal vascular disease include sudden onset of hypertension, hypertension not responsive to three or more blood pressure medications, increased urea (waste product excreted by kidneys) in blood, and unexplained kidney failure.
Diagnosing and Treating Renal Artery Disease
To evaluate your renal arteries, one or more of the following may be ordered:
ultrasound, which uses sound waves to assess the structure and function of the kidneys and how fast blood flows through the arteries
angiography, in which a dye is injected into the arteries as X-rays are taken
magnetic resonance angiography (MRA), which uses magnetic fields to visualize renal arteries
computed tomographic angiography (CTA), which images renal arteries with contrast dye to visualize renal arteries
renography, a nuclear radiology procedure which assesses the function and structure of the kidneys
Not all patients need surgery right away. Treatment for renal artery stenosis is needed in patients who have uncontrolled hypertension despite medication and severely blocked renal arteries. Once the diagnosis of significant renal artery stenosis is made, the most appropriate therapy is vascular surgery, which may include renal artery angioplasty and stenting or open surgical bypass or endarterectomy of the narrowed or blocked renal artery.
Renal Artery Angioplasty and Stenting
In the procedure, the surgeon introduces a needle into the artery in the groin after injecting numbing medicine. A catheter (flexible plastic tube) is inserted into the artery and carefully guided into the renal artery. Live X-rays, called fluoroscopy, are taken to see the artery during the procedure.
The surgeon then passes a guidewire through the catheter through the blockage. A small balloon is guided over the wire and into the blockage. The balloon is inflated and presses against the inside walls of the artery to open the artery and allow better blood flow to the kidney.
Finally, a stent (wire mesh tube) is placed across the blocked area to help keep the artery open after balloon treatment.
Renal Artery Bypass or Endarterectomy
The vascular surgeon uses a bypass to create a detour around the narrowed or blocked segments of the renal artery. The surgeon connects a man-made material, called a bypass graft, to the artery above and below the blocked area. This creates a new path for blood to flow to the kidneys.
In renal artery endarterectomy, the surgeon removes the inner lining of the renal artery which contains the plaque, thereby leaving a smooth, wide-open artery. The artery is then closed with a patch of vein.
Understanding Renal Artery Aneurysm
A renal artery aneurysm is a bulging, weakened area in the wall of an artery to the kidney. Most of these aneurysms are small (less than two centimeters, or about three-quarters of an inch) and without symptoms. Renal artery aneurysms are uncommon and are generally discovered while diagnosing other conditions.
There are four types of renal artery aneurysms:
saccular - bulges or balloons out only on one side of the artery
fusiform - bulges or balloons out on all sides of the artery
dissecting - weakened artery wall due to a tear in the inner layer of the artery wall
intrarenal - occurs on an artery inside the kidney
Saccular aneurysms may occur as a result of a congenital (present at birth) weakness of an artery wall or trauma. Atherosclerosis may also be a factor. Fusiform aneurysms most often occur with fibromuscular dysplasia. Intrarenal aneurysms may be congenital, or may result from trauma.
Renal artery aneurysm is generally asymptomatic, though hypertension may be present in up to 90 percent of patients with renal artery aneurysm.
Treating Renal Artery Aneurysm
Treatment of a renal artery aneurysm depends on factors such as size and location of the aneurysm and whether or not symptoms are present. Certain types of small (less than two centimeters, or about three-quarters of an inch) aneurysms may not be treated, but may be observed for growth or development of other complications.
Larger aneurysms (greater than two centimeters or three-quarters of an inch), dissecting aneurysms, aneurysms causing lack of blood flow to the kidneys and hypertension, aneurysms that are growing larger, and aneurysms causing symptoms may be treated surgically. Because of the increased risk for rupture, a renal artery aneurysm in a pregnant woman or a woman of child-bearing age will generally be treated surgically.
All Heart & Vascular Center vascular surgeons are certified by the American Board of Surgery and all have earned added qualifications in vascular surgery.
To make an appointment with a Washington University heart or vascular specialist at Barnes-Jewish Hospital, call 855.925.0631.