Sham Controlled Study of Renal Denervation for Untreated Stage I and II Hypertension

1. Subject is at least 18 years of age and no more than 80 years of age and can be safely removed from present antihypertensive therapy.
2. Subject has not been taking any anti-hypertensive medications for at least 6 months prior to study enrollment.
3. Subjects must have an average office seated systolic BP (SBP) between 150 mmHg and 180 mmHg inclusive in the untreated state for a minimum of 2 weeks.
4. Mean daytime ambulatory SBP > 135 mmHg and no more than 170 mmHg in addition to mean daytime ambulatory DBP > 85 mmHg.
5. Subject has two functioning kidneys.
6. Subject has an eGFR value of ≥ 30 ml/min/1.73 m² (MDRD formula).

Exclusion Criteria:

a.Any known secondary causes of hypertension.

b.Evidence of current or past history of any clinically significant renal artery stenosis on duplex ultrasound as defined by a finding of at least one of the following:

1. Peak systolic velocity (PSV) in the main renal artery of 150 cm/s or greater;
2. Renal/aortic ratio (RAR) of greater than 3.5; or
3. Complete lack of Doppler signal in any portion of the main renal artery (signifying complete occlusion).

c.Previously documented finding of a 30% or greater renal artery stenosis in any renal arterial vessels as determined by angiographic examination, MRA or CTA.

d.Kidney stones that are 1 cm or greater in size, or that are symptomatic. e.History of intra-abdominal surgery within the past six months or surgery through retroperitoneal path at any time .

f.Previous renal denervation g.Previous renal transplant. h.Heterogeneities in kidney morphology, such as large cysts or tumors (> 2 cm), which are determined at discretion of the investigator to potentially interfere with treatment.

i.Hemodynamically unstable valvular heart disease for which BP reduction would be hazardous in the judgment of the site investigator-physician.

j.Documented history of severe orthostatic hypotension that requires treatment or has necessitated hospitalization.

k.Primary pulmonary hypertension l.History of myocardial infarction, unstable angina pectoris, or cerebrovascular accident within the last six months.

m.BMI over 35 kg/m² and/or mid-arm circumference > 45 cm (creates difficulty with ABPM measurements) n.Anatomy that precludes treatment as determined by the Surround Sound System. This may include any of the following:

1. Target treatment depth as measured by the Surround Sound System of greater than 13 cm (Skin to target);
2. Lack of visualization of the renal artery and or renal artery Doppler signal with the Surround Sound System;
3. Lack of visualization of the renal parenchyma due to obscuration by bowel or other abdominal or retroperitoneal structures; or
4. Narrow window between the superior margin of the iliac crest and the inferior margin of the lowest rib that prevents adequate positioning of both the Surround Sound imaging probe and the treatment unit.

o.Subject is pregnant , nursing, or intends to become pregnant during the study period.

p.Enrollment in another interventional research protocol. q.Any condition that, at the discretion of the investigator, would preclude participation in the study.

r.Subject is unable, or unwilling, to comply with the protocol-required follow-up schedule.