Is renal denervation making a comeback?

New interest in renal denervation for the treatment of hypertension has been sparked with the results of a small proof of concept study showing the procedure works where previous trials have failed.

Early findings from the SPYRAL HTN OFF MED trial presented at the ESC and published simultaneously in The Lancet found that a more intensive approach to ablating renal nerves than the one used in the failed pivotal SYMPLICITY HTN-3 trial can reduce blood pressure in patients with mild-to-moderate hypertension who were not on blood pressure lowering drugs.

In the trial of 80 participants conducted over 21 centres, including in Australia, denervation with the Symplicity Spyral multielectrode catheter (Medtronic) resulted in a greater decline in 24-hour systolic pressure (by 5.0 mm Hg) and 24-hour diastolic pressure (by 4.4 mm Hg) in the first 3 months of follow up.

Support for renal denervation has been hampered by its chequered past – early trials suggested patients could achieve a significant drop in blood pressure with the relatively simple procedure generating a wave of enthusiasm that ground to a halt in 2014 when findings from the pivotal SYMPLICITY HTN-3 trial showed no benefit in terms of systolic blood pressure reduction compared with a sham procedure.

Since then, little has been heard about the procedure and it’s role in treating hypertension.

But for those who those who have continued to believe in the potential benefits of renal denervation the findings presented this week have been described as a ‘potential game changer’.

Speaking to the limbic Associate Professor Anthony Walton, Head of the Structural Heart Program at the Alfred Hospital in Victoria and lead investigator for the Australian arm of the trial said that while it’s still early days, the interim results from SPYRAL HTN-OFF MED are a ‘substantial outcome’.

“For what was a very small trial results have been impressively positive and will no doubt renew the enthusiasm for renal denervation world wide.

This trial was never intended to demonstrate a clear-cut benefit like it did but the fact that it has strongly suggests that it’s a real finding and will have a real impact.”

Despite the disappointing trial results from SYMPLICITY HTN-3, Professor Walton said he was spurred on to continue investigating the procedure after seeing many of his own patients achieve impressive outcomes after undergoing the intervention.

“I’ve seen patients who have seen great responses – these are people who have had difficulty with blood pressure for five or 10 years; they come in and have a denervation and all of as sudden their blood pressure is controlled.”

According to Professor Walton a number of deficiencies associated with previous renal denervation trials were identified in the lead up to the current study

He said researchers involved in the current study have worked hard to overcome those confounders.

“The early trials were done in patients who were on five drugs already and that’s very complex,” he told the limbic.

“We eliminated many variables by looking at patients not taking any blood pressure drugs – it’s a very smart way to do it.”

However Professor Walton tempered his enthusiasm by adding that long term follow up over three years would need to show that patients could achieve greater blood pressure reductions for the procedure to be worthwhile.

“The thing about renal denervation is that it’s a very simple procedure, it’s very low risk and if it does work it will be a game changer in terms of what we can offer patients.”

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