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Renal denervation

What is renal denervation?

Renal sympathetic denervation is a new treatment for hypertension (high blood pressure). Hypertension raises the risk of having a heart attack, stroke or death.  It is usually treated with lifestyle changes or medication. Nerves located in the renal artery wall communicate information from the kidney to the brain to control blood pressure. In this procedure, a device is inserted through the groin to deliver heat energy to the renal nerves with the aim of reducing blood pressure. 

Who is renal denervation suitable for?

This is a new procedure for blood pressure so there is only limited experience of the technique. So far it has been shown to be effective in reducing blood pressure for those people who have "resistant" hypertension.  This is usually a BP > 160mmHg despite being treated with at least three drugs for blood pressure. 

What does the procedure involve?

The procedure is usually carried out under local anaesthetic. A tube is inserted into the artery in the groin (femoral artery) and a catheter is placed under X-ray guidance into each of the renal (kidney) arteries in turn. Heat energy is then delivered to the renal artery in two minute bursts. Around five or six bursts of energy are given to each artery. This can be painful but this is controlled by giving painkillers into the vein during the procedure. The whole procedure lasts around an hour. You will usually stay in hospital for at least 6 hours after the procedure and sometimes may need to stay overnight. 

What are the benefits?

A randomised controlled trial of 100 patients treated by renal artery denervation showed an average blood pressure reduction of 32/12 mmHg in the renal denervation group after six months1. A case series of 153 patients reported an average blood pressure reduction of 25/11 mmHg at six months, 26/14 mmHg at 12 months and 32/14 mmHg at 24 months2. Not everyone had this level of blood pressure reduction. Around 1 in 10 people did not have much benefit from the treatment. There is no long term data (beyond two years). Most people carried on with all their medication after the procedure. 

Are there any risks?

The most serious risk is dissection of the renal artery. This happened in one patient out of 153 and can be treated with a stent at the time2. Other adverse events include the risk of bruising or bleeding in the groin, nausea and back pain. These usually subside but may take up to a month. There have not been any reports of damage to kidney function but this is a theoretical risk. NICE are in the process of producing their evaluation of this procedure.


  1. Renal sympathetic denervation in patients with treatment-resistant hypertension (The Symplicity HTN-2 Trial): a randomised controlled trial. Symplicity HTN-2 Investigators, Esler MD, Krum H, Sobotka PA, Schlaich MP, Schmieder RE, Böhm M. Lancet. 2010 Dec 4;376(9756):1903-9.
  2. Catheter-based renal sympathetic denervation for resistant hypertension: durability of blood pressure reduction out to 24 months. Symplicity HTN-1 Investigators. Hypertension. 2011 May;57(5):911-7. 

Read about the experience of one our renal denervation patients