Download Catheter-based Renal Denervation for Poorly Controlled Hypertension

Catheter-based
Renal Denervation
for Poorly Controlled
Hypertension
A patient’s guide
Why is hypertension important?
Long standing hypertension (high blood pressure) increases the risk of heart attack, stroke,
heart failure, kidney disease and death. Because of these risks, the disease is treated
aggressively with lifestyle changes and prescription medication. Unfortunately, in many
patients these steps alone are not enough to control blood pressure. Also some patients have
troublesome side-effects from medications and may not be able to take these
What is renal (kidney) denervation?
This new procedure is a major advancement in the treatment for hypertension.
The procedure involves passing a tube from the groin artery to the renal artery and quietening
the sympathetic nerves to the kidney by “zapping” them with radiofrequency energy.
Trials show it is effective in reducing blood pressure in patients with poorly controlled
hypertension despite medication.
The response seems to be long lasting, although patient follow-up so far is only a few years.
Patients will usually need to continue hypertension medications after the procedure,
but their blood pressures are much better controlled. Sometimes the dose of medications can
be reduced and sometimes they can be stopped altogether.
What are the renal sympathetic nerves and why are they
important in hypertension?
One of the body’s main methods for controlling blood pressure involves the sympathetic
nervous system. This system links the major organs that are responsible for regulating blood
pressure: the brain, the heart, the kidney and the blood vessels themselves. The kidney is
particularly important for blood pressure control. Renal sympathetic nerves communicate
information from the kidney to the brain, and vice versa.
In people with hypertension, the sympathetic nervous system is overactive, raising blood
pressure and contributing to heart, kidney and blood vessel damage. Quietening the renal
nerves can interrupt the overactive sympathetic nervous system thus reducing some of the
triggers for that cause hypertension. This may protect the heart, kidney and blood vessels
from further damage.
In addition some patients have improved diabetes control because the sympathetic nervous
system is involved with blood sugar control.
What does the renal denervation procedure involve?
You will be admitted to a ward several hours before the procedure, then transferred to the
angiography suite (“Cath Lab”). You will be given sedative medication and local anaesthesia
is injected around the groin artery in preparation for passing a catheter (thin tube) from the
groin artery to the renal (kidney) artery. You cannot feel the catheter moving inside you. Most
patients will feel some pain when the sympathetic nerves are “zapped”. This lasts only a short
time and is controlled by medication. Both left and right renal arteries need to be treated. After
completion of the procedure the catheter is removed from the groin and pressure applied until
the artery seals. You will need to stay in bed for some hours and you will be discharged the
same day or the next day.
What are the side effects?
Most patients have pain when the artery is being “zapped”. The duration of “zapping”
is two minutes and this occurs about 10 times. You will be given medication to reduce
this discomfort.
There may be problems at the groin artery puncture site such as haematoma.
The procedure has been remarkably free of complications to date, but injury to the kidney
artery is possible.
10% of patients may not have improved blood pressure control.
Who is suitable for Renal Denervation?
Patients with poorly controlled hypertension despite medication may be considered.
Patients will need a consultation with a cardiologist or other hypertension specialist.
Patients may not be suitable if they have narrowed renal arteries or if they have more than
one renal artery to a kidney.
How can I be referred for consideration for catheter based renal
denervation?
Your family doctor or specialist may wish to refer you to an Auckland Heart Group Cardiologist
(see below for a list) or other specialist in hypertension treatment, for an assessment of need
and suitability. There will be a consultation, blood tests, blood pressure monitoring tests and
perhaps some imaging tests.
How can I find more information?
Mercy Angiography Website
www.mercyangiography.co.nz
Ardian Inc
www.ardian.com
Ria Bakker
[email protected]
Telephone 64 9 6301 961
Compiled by
Associate Professor John Ormiston
MBChB, FRACP, FRACR, FCSANZ, FAPSIC, FRCP (Lond), FACC, ONZM
Interventional Cardiologist and Medical Director
Mercy Angiography Unit