Renal Denervation gets FDA approval

How Recor's ultrasound lowers blood pressure when lifestyle changes & medications fall short

Nov 12, 2023

Signals From [Space] explores the frontiers of healthcare technology. We’ve spent much of the past two months exploring major themes in kidney care, rolling up stories and science into thematic bursts of insight across topics like diagnostics, remote monitoring, and value-based care.

Today we take our first dive into a breakthrough medical device that’s top of mind for many in this audience. As with every Signals issue, my goal is to bring you to the frontlines of innovation without getting lost in the vast expanses of healthcare and technology.

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Thank you, Keith

Keith R. (left) with Dr. Kirtane (right). *Credit: Columbia*

One day after FDA approval, Keith became the first patient at Columbia to undergo a first-of-its kind ultrasound-based renal denervation (RDN) treatment to lower blood pressure.

Dr. Kirtane, who currently serves as Director of Columbia’s Interventional Cardiovascular Care program, has led pivotal studies showing the efficacy of this treatment option for several years now.

Last week, after more than a decade of work, Otsuka subsidiary Recor Medical received FDA approval for its Paradise ultrasound renal denervation system to treat hypertension.

This makes Recor the first company to offer the RDN treatment in the United States. Paradise received its CE mark in 2012 and is an investigational device in Japan.1

What is RDN?

Renal denervation (RDN) is meant to be used as an adjunctive therapy when lifestyle modification and medications fail to control a patient’s blood pressure.2

Recor’s RDN treatment is a minimally invasive procedure where ultrasound energy is delivered through the renal arteries to disrupt signals from the surrounding nerves, with the idea that reducing activity in the renal nerves can lower blood pressure.

A rendering of Recor’s Paradise renal denervation catheter within an artery. The red circle indicates the heat generated from the ultrasound energy in the tissue delivering energy. The blue circle indicates cooling from circulating water to protect the artery. *Courtesy of Recor.*

The Paradise system delivers two to three doses of 360-degree ultrasound energy — lasting seven seconds each — through each of the main renal arteries to the surrounding nerves (red circle).

The Paradise catheter features the exclusive HydroCooling™ system, which circulates sterile water through the balloon catheter during the procedure to help protect the renal artery wall (blue circle).

Pictured below, Mano Iyer, who founded Recor in 2009. Mano currently serves as a Venture Partner at Paris-based Sofinnova Partners, who incubated Recor from inception and sold it to Otsuka in 2018.

Mano Iyer at LSI Europe ‘23. *Credit: LSI*

Why it matters

Nearly 1 in 2 US adults has high blood pressure, or hypertension. It also happens to be one of the costliest of all heart diseases — annual medical costs for people with hypertension are up to $2,500 higher than those without it. And if that somehow hasn’t grabbed your attention, you should know about 650 million prescriptions for blood pressure meds are filled each year.3

Clearly a proverbial “magic pill” for hypertension eludes us mere mortals. Despite having many available treatment options, a significant subset of the population continues to grapple with uncontrolled blood pressure. Because of this, millions of patients remain vulnerable to severe health risks such as heart failure, stroke, heart attacks, and irreversible kidney damage.

The interplay between kidney nerves and hypertension forms the crux of this innovative therapeutic approach known as RDN.

Individuals often experience hypertension stemming from hyperactive nerves in the kidneys, triggering processes that elevate blood pressure. While existing antihypertensive medications provide crucial support, they do not directly target the renal nerves. That’s where RDN comes in.

What’s Next

There are still plenty of open questions about RDN and where the field goes from here. At the annual TCT meeting that took place in October, experts from the field gathered for an FDA Town Hall session to discuss these perspectives and open questions. Here’s a glimpse of that discussion:

Lessons & Obstacles

Medication use remains the most important confounding factor that needs to be addressed when conducting future renal denervation studies. Dr. Felix Mahfoud from Saarland University Hospital in Germany is a long-term trialist in this space underscored the importance of standardizing medication use by showing how differential drug use between the two arms caused a few studies to miss their primary endpoints.
It is difficult to overcome the skepticism about renal denervation that has become entrenched over the past decade. Dr. Naomi Fisher from Brigham and Women’s Hospital in Boston said that despite that skepticism, there has been knowledge gained, like (a) the power of placebo, (b) how patient behavior changes in response to being observed (the Hawthorne effect), (c) the importance of avoiding measurement bias and eliminating variability in technique, (d) conducting appropriately designed studies, and (e) about medication adherence and the large impact combination therapy can have.
We still lack measures of procedural efficacy during denervation. Other missing puzzle pieces include: (a) factors predictive of who will respond to the intervention, (b) incorporation of patient preference and patient-reported outcome measures into trials, and (c) research into how denervation works in specific patient subsets, including those with isolated systolic hypertension, diabetes, and chronic kidney disease or groups that have been underrepresented in trials thus far, like women and those from racial/ethnic minority groups.
Uptake remains low. Dr. Horst Sievert from CardioVascular Center Frankfurt pointed out that renal denervation has not been taking off in Germany and elsewhere despite the positive clinical trials. He said acceptance is low because of the modest size of the blood pressure reductions and the fact that it is an invasive and irreversible procedure.
Not everyone is sold on RDN, at least not yet. Comments on X suggest the jury is still out for physicians who want to see longer term durability, success markers, cost effective analysis, reimbursement, and clear clinical outcomes data. Not to mention comparisons to similar BP reduction from “$0.05 per day pills.”4