Hyperactivation of the sympathetic nervous system, and in particular excess neural activity to and from the kidneys, is a major contributor to the underlying pathophysiology of hypertension. Results of several previous studies suggest that a novel, minimally-invasive, catheter-based treatment to target the renal nerves may be useful in lowering blood pressure. This procedure is performed by advancing a special catheter into the renal arteries and delivering low-power radiofrequency energy to interrupt the renal afferent and efferent nerves. The resultant decrease in the renal contribution to central sympathetic drive and in turn reduces blood pressure.
More than 275 patients have been treated with renal sympathetic denervation in clinical studies to date. In the Symplicity HTN-2 Study, a randomized, controlled trial in patients with uncontrolled hypertension, significant blood pressure reduction was observed in the treatment arm (-32/-12 mmHg), compared with no change in the control arm (1/0 mmHg). Moreover, all renal denervation procedures in the treatment arm were performed without significant complications.
Symplicity HTN-3 is a multi-center, prospective, blinded, randomized, controlled trial that will study patients with a systolic blood pressure ≥ 160 mmHg despite treatment with 3 or more anti-hypertensive medications. After an initial screening period, eligible patients will be randomized “on the table” after renal angiography in a 2:1 ratio to a treatment arm (renal denervation plus maintenance of baseline medications), or a control arm (maintenance of baseline medications alone). The primary outcome measure will be blood pressure at 6 months. Control patients will be given the option to undergo renal denervation after the 6 month follow-up. Long term follow-up will be through 36 months.
Inclusion criteria for Symplicity HTN-3 include the following:
- Age 18-80 years at randomization
- On a stable medication regimen including full doses of ≥3 anti-hypertensive medications of different classes, of which one must be a diuretic (with no changes for a minimum of 2 weeks prior to screening) that is expected to be maintained without changes for at least 6 months.
- Office systolic blood pressure of ≥ 160 mmHg based on an average of 3 blood pressure readings measured at both an initial screening visit and a confirmatory screening visit
Exclusion criteria are as follows:
- Renal artery anatomy that is ineligible for treatment
- Ambulatory blood pressure monitoring (ABPM) 24-hour average systolic blood pressure < 135 mmHg
- Estimated glomerular filtration rate (eGFR) of < 45mL/min/1.73m2
- In-patient hospitalization for a hypertensive crisis within the past year
- Type 1 diabetes mellitus
- Pregnant, nursing or planning to be pregnant
This study represents an opportunity for patients with resistant hypertension to participate in the evaluation of a novel and promising form of therapy that is not otherwise available in the US.
Drs. Rick Stouffer and Alan Hinderliter are the Co-Principal Investigators for Symplicity HTN-3 at the UNC site, with collaborating investigators from the Division of Nephrology and Hypertension and the Department of Family Medicine. Cassie Ramm, RN, BSN is the research nurse. Please contact Rick, Alan, or Cassie at 843-1610 if you have patients that may be eligible for participation.
More information on the trial is available at http://www.symplifybptrial.com/