Background:
Invasive catheter based techniques for renal denervation have been extensively examined in treating patients with resistant hypertension, with mixed results and some periprocedural complications. New evidence suggested that not all renal nerves are in the range of invasive procedures limited to a distance 4 to 6 mm from the lumen.
Aims:
To evaluate the safety and efficacy of an entirely non-invasive approach to renal denervation using externally delivered focused ultrasound to the peri-renal artery tissue with real time Doppler-based image guidance.
Methods and results:
Twenty-seven patients with severe, treatment resistant hypertension, defined as persistent systolic blood pressure (BP) > 160 mmHg despite 3 or more antihypertensive medications, were treated non-invasively with the Kona Medical Surround Sound System™. Focused ultrasound energy was delivered to the renal arteries bilaterally and surrounding tissue using Doppler-based imaging and continuous tracking with automatic correction for kidney motion throughout treatment. Patients received conscious sedation during the treatment period.
At this time, all patients have completed 24 weeks and 23 patients 52 weeks of follow up. Post-denervation, the mean changes from baseline BP (175/92 mmHg) were -16.8/-8.6 mmHg at 3 weeks, -23.2/-10.8 mmHg at 6 weeks, -29.7/-13.1 mmHg at 12 weeks, -21.6/-8.7 mmHg at 24 weeks and -25.6/-10.1 mmHg at 52 weeks . No serious device-related events have been reported to date. Forty-one percent of subjects (11/27) reported mild back pain immediately following the denervation treatment. The majority of cases (7/11) completely resolved within three days post treatment without any significant intervention and no case was associated with any motor, sensory deficits.
Conclusions:
This is the first study in humans using a non-invasive renal denervation system in severe resistant hypertension. Results showed clinically meaningful reductions from baseline in office BP through 52 weeks post-denervation. The procedure was well-tolerated with no serious adverse events. This technology should enable patients to benefit from renal denervation therapy without the invasive risks associated with catheter based techniques.
PREDICTORS OF BLOOD PRESSURE RESPONSE IN THE NON-INVASIVE RENAL DENERVATION STUDY USING EXTERNALLY DELIVERED FOCUSED ULTRASOUND IN SEVERE RESISTANT HYPERTENSION
