Renal Artery Intervention for Hypertension and End-Stage Renal Disease

WHAT IS RENOVASCULAR DISEASE?

Arteries in the kidneys may be narrowed due to web-like narrowings (fibromuscular dysplasia) or build up of plaque in the arterial wall (atherosclerosis, renal artery stenosis). This results in decreased blood flow to the kidney which results in constriction of the arteries throughout the body, causing increased blood pressure.

“String of beads” appearance to right renal artery from Fibromuscular dysplasia: a cause of high blood pressure. The patient responded well to angioplasty

WHAT ARE THE EFFECTS OF HIGH BLOOD PRESSURE?

Increased blood pressure puts stress on the organs in the body, including the heart, the kidneys and the brain. In the kidneys, this is a major cause of end-stage renal failure. People with end-stage renal disease require dialysis or kidney transplants.

WHY TREAT RENOVASCULAR DISEASE?

High blood pressure is common in our population. Most people can be treated with lifestyle changes and medication. However, there is a small group of people who have high blood pressure secondary to renovascular disease who would benefit from treatment.

HOW CAN WE DIAGNOSE RENOVASCULAR DISEASE?

Renovascular hypertension requires consideration in younger patients or when blood pressure is difficult to control on multiple medications.

Blood tests can determine kidney function and imaging studies can assess the renal arteries. Renal doppler ultrasounds are non-invasive and may be used as a first line investigation. A CT angiogram is useful for looking at the renal arteries and to also assess the other abdominal organs.

CT Angiogram demonstrates high grade narrowing (stenosis) in renal artery
CT Angiogram demonstrates high grade narrowing (stenosis) in renal artery

HOW CAN WE TREAT RENOVASCULAR DISEASE?

If lifestyle changes and medical treatment are not sufficient, endovascular techniques for blood flow restoration may be used. The aim of this treatment is to restore normal blood pressure, reduce the number of medications and prevent declining kidney function.

Patient with high blood pressure and stenosis (narrowing) of right renal artery
Patient with high blood pressure and stenosis (narrowing) of right renal artery

The arteries to the kidney can be opened using endovascular techniques. After administration of local anaesthetic and sedation, a small puncture of the artery in the groin is performed. A thin, soft, flexible wire is then advanced to the affected artery and it is opened with angioplasty (balloon dilatation) or stenting (keeping the artery open with an implantable metallic scaffold). Technical success is confirmed with an angiogram. The procedure is done as a day-only procedure and the patient can normally return home after a short period of observation.

Balloon mounted stent deployed across renal stenosis
Balloon mounted stent deployed across renal stenosis

Restoration of calibre and flow post renal artery stenting. Patient was able to cease blood pressure medications.
Restoration of calibre and flow post renal artery stenting. Patient was able to cease blood pressure medications.