As real-world renal denervation use begins, an interventionist shares experience, cautions
Click Here to Manage Email Alerts
Key takeaways:
- Two FDA-approved renal denervation systems are now commercially available in the U.S.
- The devices are approved for people with persistent hypertension despite use of at least three maximally tolerated drugs.
In November, the FDA approved two renal denervation devices for people with uncontrolled hypertension despite maximally tolerated therapies. The approvals ushered in the first-ever interventional procedures with indications to lower BP.
The ultrasound renal denervation system (Paradise, Recor) lowers BP by denervating the sympathetic nerves surrounding the renal arteries, reducing the overactivity that can lead to hypertension. A second radiofrequency renal denervation system (Symplicity, Medtronic) similarly ablates the renal nerves with heat energy, leading to a drop in BP. After the approvals, Cleveland Clinic, which participated in the pivotal trial for the Paradise system, became one of the first hospitals to perform ultrasound renal denervation on a patient. The procedure offers a new option for patients with uncontrolled high BP after other options have failed, according to Aravinda Nanjundappa, MBBS, MD, interventional cardiologist at Cleveland Clinic, who performed the first procedure.
Healio spoke with Nanjundappa about how renal denervation works, performing the procedure outside of a clinical trial, and cautions about future use of the devices.
Healio: There are many antihypertensive medicines available. Why was there a need for an option like renal denervation?
Nanjundappa: Approximately 1.28 billion adults globally have hypertension. Of those, one in five is uncontrolled. Resistant hypertension is defined as a BP of 140/90 mm Hg despite the use of three antihypertensive medications from three different classes, one of which is a diuretic. With a consistently elevated BP, a person is at increased risk for CV events, including stroke, MI and HF. For these patients, adding another antihypertensive medication may seem like a good idea; however, the more medications you add, the less likely it is a patient will take them as prescribed. Diuretics also have their own side effects, so patients may stop taking them.
Healio: How does the ultrasound renal denervation system work?
Nanjundappa: There are two companies with FDA-approved renal denervation devices, Recor Medical and Medtronic. Both companies conducted many clinical trials with these devices. Recor’s Paradise ultrasound renal denervation system was the first one FDA approved. It has a catheter with a balloon. Inside of the balloon is a transfuser that emits ultrasound energy, which can cause denervation of the nerves. The name of the transfuser that emits the ultrasound, the SonoWave 360, delivers two to three doses of 360° ultrasound energy through the main renal arteries to the surrounding nerves, reaching approximately 80% of the sympathetic nerves in the renal artery. The sympathetic nerves are the nerves that come from the aorta and go into the renal parenchyma. These nerves are the same ones that are stimulated and send the response to the brain to increase the BP. With renal denervation, you are trying to “cut off” that circuit so these nerves do not transmit the signal from the renal arteries to keep the BP elevated. We know most of the sympathetic nerves are within 6 mm of the artery. The energy is delivered in 7-second bursts. At the same time, this technology provides hydrocooling to protect the renal artery wall.
Both devices are easy to use. More options are better because that drives competition and improved outcomes.
Healio: Can you describe your experience using the Paradise renal denervation system?
Nanjundappa: It is pretty straightforward. Someone with vascular intervention experience should perform the procedure, as it is a delicate issue and you do not want to damage the renal arteries. The patient undergoes a renal angiogram, and then you place the wire into the renal parenchyma and size the balloon catheter according to the size of the artery. The whole procedure, for us, took less than 1 hour. We then perform a renal angiogram.
Healio: The FDA label indication for both of the renal denervation devices — to treat adults with hypertension not adequately controlled with lifestyle changes and medications — is pretty broad. Who might be the appropriate patients for this treatment and how will you and your team select who those patients are?
Nanjundappa: The indication is broad, but we should stick to what works. At Cleveland Clinic, a good candidate has an office BP and ambulatory BP of 140/90 mm Hg or higher despite taking at least three maximally tolerated antihypertensive medications. If a patient is prescribed fewer than three antihypertensive medications, they must demonstrate intolerance to the medicines they are not taking. Not everyone can tolerate certain BP medications due to conditions such as a low heart rate or certain drug allergies. The patient must also have an interest in undergoing a procedure. Exclusion criteria include renal artery stenosis or a stent, or an estimated glomerular filtration rate of 30 mL/min/1.73 m2 or lower, as we do not have clinical trial data on such patients.
Healio: What should clinicians keep in mind when discussing renal denervation with their patients?
Nanjundappa: Lifestyle changes remain fundamental for BP control. Clinicians should counsel patients to eat a healthy, low-salt diet with plenty of fruits and vegetables, get regular daily exercise and try to get adequate amounts of sleep. Data show sleep deprivation is one of the most important contributors to hypertension. If people do not get 8 hours of sleep per night, BP stays high. Patients must also work to manage stress as best they can and there are various techniques to help with that. Those lifestyle changes will help.
If lifestyle adjustments fail to lower BP, then consider antihypertensive medications. If BP remains high despite use of multiple antihypertensive medications and lifestyle changes, then renal denervation is an option. This is not an option for any person coming off the street with hypertension.
Healio: This is still very new technology. Going into 2024 and beyond, do you see renal denervation as something that will become fairly widely adopted?
Nanjundappa: I think so. However, at the same time, we need to pay attention to who uses these devices. We do not want to go beyond the device label indications and risk complications by performing this on patients who did not meet the criteria for the clinical trials.
I tell people that performing a procedure during a clinical trial is a lot like taking a brand-new car from the showroom out for a test drive. Someone is watching you. You will, of course, be extra careful because the car you are driving is not yours. Once you own the car, you become more comfortable, but you may do things like speeding or texting while driving. That is when accidents happen. Same thing performing a procedure during a clinical trial vs. the real world. The trials are well regulated, there is a proctor and someone from the company there watching. Yes, renal denervation will add a new paradigm to the treatment of hypertension, but we do need to stick to performing this procedure on the patients who will benefit most. There are also questions of reimbursement for these procedures. Hospitals have to figure out how to pay for this.
Reference:
- Cleveland Clinic among first hospitals to perform new renal denervation therapy for uncontrolled hypertension. Available at: https://newsroom.clevelandclinic.org/2023/11/10/cleveland-clinic-among-first-hospitals-to-perform-new-renal-denervation-therapy-for-uncontrolled-hypertension/. Published Nov. 10, 2023. Accessed Dec. 15, 2023.
For more information:
Aravinda Nanjundappa, MBBS, MD, can be reached at dappamd@yahoo.com.
Collapse
Healio Interviews
Read more about
Click Here to Manage Email Alerts