There were no safety or effectiveness concerns. There were concerns about completing enrollment due to a competitive device's potential approval.

The purpose of the EnligHTN IV clinical investigation is to demonstrate the safety and effectiveness of the EnligHTN™ Renal Denervation System in the treatment of subjects with drug-resistant uncontrolled hypertension.

The study enrollment was terminated early by the sponsor. This was not related to any safety issue. At the time enrollment was halted, only 2 treatment group randomizations had occurred, and sham group subjects were exited after their 1 month follow up visit.

Subject randomized to the treatment group will be followed up for three years post procedure.

Inclusion Criteria:

• Subject is ≥18 years of age and ≤ 80 years of age at time of informed consent for participation in the clinical investigation

• Subject must be able and willing to provide written informed consent

• Subject must be able and willing to comply with the required follow-up schedule

• Subject has an office Systolic Blood Pressure ≥ 160 mmHg based on an average of 3 Blood Pressure readings at the confirmatory visit (except for subjects with Diabetes Mellitus Type II who must demonstrate an office Systolic Blood Pressure of ≥ 150 mmHg)

• Subject has a daytime mean Systolic 24-hour Ambulatory Blood Pressure value of ≥ 140 mmHg as measured during the two week screening period and confirmed at the confirmatory visit

• Subject is taking ≥ 3 antihypertensive medications concurrently at full tolerated doses (this must include one diuretic) or subject is taking a diuretic and has a documented intolerance to at least two (2) out of the three (3) remaining major classes of anti-hypertensives (ACE / ARB, Calcium Channel Blockers, Beta blockers and is unable to take 3 anti-hypertensive drugs)

  o Intolerance is defined as an absolute contraindication to an anti-hypertensive medication according to the approved labeling or an inability to take an anti-hypertensive medication as prescribed due to an adverse drug effect including an immune mediated response or interaction with other medications.

• Subjects must be on a stable antihypertensive medication regimen for a minimum of 2 weeks prior to completing the initial screening visit and the medication regimen must remain unchanged during the 2 week screening period following signing consent. Subject must be assessed at the confirmatory visit with no expected changes for at least six (6) months

Exclusion Criteria:

• Subject has had a previous renal denervation attempt
• Subject has known cause of secondary hypertension other than sleep apnea
• Subjects with significant renovascular abnormalities such as renal artery stenosis >30%, previous renal stenting or angioplasty, renal artery occlusion, renal vein thrombosis, renal aneurysm or renal atheroembolism
• Subject has had a myocardial infarction, unstable angina pectoris, or cerebrovascular accident < 180 days prior to enrollment
• Subject has hemodynamically significant valvular heart disease as determined by a Study Investigator
• Subject is expected to have any cardiovascular intervention within 180 days of enrollment
• Subject has blood clotting abnormalities such as thrombocytopenia, hemophilia, or significant anemia
• Subject life expectancy is < 12 months, as determined by a Study Investigator
• Subject is participating in another Clinical Investigation (IND or IDE)
• Subject is pregnant, nursing, or of childbearing potential and is not using adequate contraceptive methods
• Subject has active systemic infection as determined by a Study Investigator
• Subject has main renal arteries with diameter(s) < 4 mm in diameter or < 20 mm in length or multiple renal arteries where the main renal arteries supply <75% of the kidney
• Subject has eGFR < 45 mL/min per 1.73 m2 using the MDRD formula
• Subject has evidence of significant AAA defined as an aneurysm size of ≥5.0 cm in width and/or involving the renal arteries, and/or requiring surgical or percutaneous intervention within 6 months of enrollment.
• Subject has had >1 in-patient hospitalization for a hypertensive crisis within 12 months
• Subject has a condition which would interfere with the accurate interpretation of the study endpoints
• Any condition that would prohibit or interfere with the ability to obtain accurate Blood Pressure measurements using the CIP specific automatic Blood Pressure monitor
• Subject has Systolic Blood Pressure values which are greater than 20mmHg apart after six (6) measurements as assessed at the confirmatory visit

All subjects enrolled.

Ongoing through 3 years post procedure

All events were adjudicated by an independent Clinical Events Committee. Current events included through last annual report (April 2015)

Enrollment ended early due to a sponsor decision unrelated to safety. The 2 treatment group subjects are being followed up through 3 years. The 2 sham group subjects were exited after their 1 month visit. Due to these reasons, data is limited.