Circumferential ultrasound heating is potentially a more uniform and effective method for performing renal denervation than radiofrequency systems, Marc Sapoval, Department of Cardiovascular Radiology, European Hospital Georges Pompidou, Paris, France, told delegates at the CIRSE annual meeting (15–19 September, Lisbon, Portugal).
Sapoval presented six-month results from the REDUCE trial, the first-in-man study of endovascular ultrasound renal denervation with the Paradise system (ReCor Medical) for the treatment of resistant hypertension. He explained that the system, which received the CE mark in December 2011, consists of an intravascular, catheter-based approach that, as with radiofrequency, is achieved by inducing thermal necrosis.
“Ultrasound energy consists of sound waves that pass through the fluids and generate frictional heating in soft tissue,” he said. “No direct contact is required, and energy can be emitted circumferentially.” He added that, with this device, “cooling the arterial wall minimises damage to non-target tissues; the self-centred transducer enables controlled and uniform energy delivery; and circumferential heating allows for more rapid treatment, therefore reducing procedure times”.
Fifteen consecutive patients with resistant hypertension as defined by the European Society of Hypertension/European Society of Cardiology guidelines were enrolled in the REDUCE study in South Africa. All patients were on a minimum of three anti-hypertensive medications including a diuretic at baseline (average five medications). The mean age of patients was 52 years (32–80 years), and 60% were men. Enrolment was completed in May 2012. The principal investigator of the study was Tom Mabin, Somerset West, South Africa.
Sapoval noted that, at baseline, the average systolic and diastolic blood pressure measurements were, respectively, 182±22mmHg and 111±15mmHg in the office, 170±21mmHg and 101±14mmHg at home, and 173±19mmHg and 102±16mmHg in ambulatory.
Bilateral denervation was performed by delivering an average of 5.5 ultrasound emissions in each patient. The average heating time was 4.3 minutes per patient. There was an average of 23 minutes between the first and the last emissions. There was no need for general anaesthesia, only sedatives and analgesics.
Sapoval presented data of 11 patients who completed six months of follow-up. In these patients, the reduction seen in office blood pressure was 32mmHg systolic and 17mmHg diastolic. The ambulatory blood pressure reduction was 13mmHg systolic and 8mmHg diastolic.
Ultrasound renal denervation, Sapoval said, “Was shown to be efficient in lowering blood seen in the Paradise system preserves the artery and prevents subsequent pressure in patients with resistant hypertension”. He added that high flow rate cooling featured complications.
Sapoval said that the Paradise clinical programme also includes the REALISE study, which is currently enrolling 20 patients at two sites in France, and the ACHIEVE study, which will enrol 50 patients at nine European sites and will start by the end of 2012.