Radiofrequency renal denervation (RDN) has the ability to disrupt the nerves in adventitia (outer layer of the artery wall) by applying heat directly to the endothelium. Ultrasound energy consists of high-frequency sound waves that pass through fluids and generate frictional heating in soft tissues, without requiring any direct contact to the tissue. The energy is delivered volumetrically to a specific target limiting extensive heating of intervening or adjacent tissues, allowing ultrasound energy to be delivered within the blood vessel from a distance, without any direct contact.
Ultrasound renal denervation is a technique that does not “touch” the intima of the artery and applies energy at 3601 allowing for less manipulation and good catheter stability. Furthermore, ultrasound RDN destroys the renal nerves without damaging the arteries. The blood absorbs very little ultrasound energy and acts as coolant for the arteries, reducing endothelial (intimal/ inner layer) damage and offering deeper penetration into the arterial tissue. Leading companies currently pursuing ultrasound based renal denervation are Paradise, Sounds Interventions, and Tivus.
PARADISE Ultrasound Renal Denervation
Paradise Catheter System
The pioneers for ultrasound renal denervation, the PARADISE catheter system (ReCor Medical, Inc) has an automated generator designed with the aim of allowing complete circumferential denervation using a 6-Fr compatible catheter. At the distal end of the catheter is an ultrasound tranducer within an inflatable low-pressure balloon. The balloon is inserted over a 0.014″ angioplasty wire through a 6 Fr guiding catheter engaged in the renal artery. Once activated, the ultrasonic sound waves are emitted in a circumferential manner from the central core of the balloon and require a 30 second treatment in each renal artery.1 The Paradise renal denervation control unit automatically controls the balloon inflation, fluid flow, energy delivery as well as real time safety checks.
The PARADISE received CE Mark approval in 2012, being the first CE-marked system for renal denervation based on ultrasound.1
The first –in-man study, the REDUCE trial, was a single-arm, open-label trial that enrolled 15 patients and showed an average sustained reduction of -30 mmHg systolic blood pressure at 1-year follow-up. Two patients experienced stenosis requiring stent intervention. There were no complications at the puncture site; however abdominal or lower back pain was seen in 63% of the patients following intervention which resolved within a few days.
The PARADISE REALISE enrolled 20 resistant hypertensive patients as a single arm open label study evaluating safety and efficacy. At TCT-2013 preliminary results from 6 months follow-up of the study showed a mean reduction of -21/9 mmHg in office blood pressure and -9/4 mmHg in ABPM. Adverse events included no renal artery stenosis/aterial damage was seen on systematic imaging of the renal arteries.
ACHIEVE is a single arm, multi-center, post marketing study of the Paradise system evaluating the safety and effectiveness in a 100 patients expected to complete enrollment by mid-2014. For more information visit:
The system provides real time temperature and position feedback without the need of contrast. Treatment time is 30 seconds per renal artery. The catheter does not alter blood-flow in the renal artery and causes no endothelium damage. There is no flow occlusion and can be used for in-stent treatment. The first-in-man study used an unidirectional Tivus (first-generation) that successfully treated 18 resistant hypertension patients with the primary endpoint of the safety and performance of the TIVUS system. Three month follow-up data shows significant reduction in systolic and diastolic blood pressure with one significant adverse event (access site hematoma).
The fourth generation catheter will be a multi-directional catheter that gives real time feedback of the denervation effect which can be used for trans-radial access. The TivusTM-II study will enroll 80 severe resistant hypertension patients at 15-20 centers across Australia, EU, and Israel.
The Sounds intervention catheter is an 8 Fr standard sheath and ultrasound energy is delivered circumferentially up to 2 applications in each artery not lasting longer than 2 minutes per patient. Results of first in man study in 10 patients with resistant hypertension showed office based blood pressure showed an average decrease of 25.6/12.5 mm Hg 3 months after the procedure. Additionally 24-hour blood pressure measurements demonstrated a mean reduction of -23.1/11.9 mm Hg.2
- Mabin T, Sapoval M, Cabane V, et al. First experience with endovascular ultrasound renal denervation for the treatment of resistant hypertension. Euro Intervention. 2012;8:57-61
- Sounds Interventions Updates Results from “Sounds-ITV” Trial of Ultrasound-Based Renal Denervation for Resistant Hypertension. Sounds Intervention Press Release. August 14, 2012. de