Renal Denervation Lowers Blood Pressure in Hypertension Patients in Ardian US Pilot Study

October 22, 2009—Study results showing that catheter-based renal denervation yields significant and sustained reductions in blood pressure in patients with multidrug-resistant hypertension were presented at the Vascular Interventional Advances meeting in Las Vegas, Nevada, by Krishna Rocha-Singh, MD, FACC.

The Symplicity HTN-1 study, sponsored by Ardian, Inc. (Palo Alto, CA), was a United States–based pilot evaluation of the safety and blood pressure–lowering efficacy of percutaneous renal sympathetic denervation in patients with resistant hypertension. Twenty patients were enrolled, 15 of which had qualifying anatomy. Inclusion criteria included having an office systolic blood pressure ≥ 160 mm Hg, despite taking 3 or more antihypertensive medications (including diuretic), and an estimated glomerular filtration rate (eGFR) of ≥ 45 mL/min/1.73m². Exclusion criteria included renovascular abnormalities, such as significant renal artery stenosis, previous renal stenting or angioplasty, dual renal arteries; having a known secondary cause of hypertension other than sleep apnea; having type I diabetes mellitus; having a hemodynamically significant valvular disease; currently taking clonidine, rilmenidine, systemic corticosteroids, or warfarin; and pregnancy. Three sites in the United States enrolled patients between September 2008 and July 2009 (Prairie Heart Institute, Springfield, IL; Hennepin County Medical Center, Minneapolis, MN; MetroHealth, Cleveland, OH).

Of the treated patients, 20% had coronary artery disease and 33% had diabetes mellitus II. At baseline, patients were taking an average of 5.2 ± 1.3 antihypertensive medications, had blood pressure levels of 173/96 ± 12/15 mm Hg, and had eGFR rates of 84 ± 21 mL/min/1.73m².

The median procedure time was 43 minutes (interquartile range, 38–51), and patients received an average of 4.4 treatments in each renal artery. Intravenous narcotics and sedatives were used to manage pain during delivery of the radiofrequency energy. There were no complications in 14 of the 15 patients (one patient developed a pseudoaneurysm at the groin access site, which was treated without further sequelae). Additionally, there were no orthostatic or electrolyte disturbances, chronic renal complications, or RF-related vascular complications. In one patient, a preexisting renal artery stenosis progressed (from 40% to 80%)—possibly related to catheter manipulation—and was stented successfully.

The results (93% responder rate) showed an average decrease in blood pressure of -28/-10, -24/-8, and -30/-13 mm Hg at 1 month, 3 months, and 6 months, respectively. Four patients had their medications reduced (by an average of three medications), and no patients had their medications increased.

"These results demonstrate that percutaneous, catheter-based, therapeutic renal sympathetic denervation is simple and safe. This pilot study independently confirms results from studies in Europe and Australia previously reported in The Lancet," Dr. Rocha-Singh said. Symplicity HTN-2, a randomized, controlled trial using Ardian's Symplicity catheter system, is currently underway in Europe and Australia, with plans to conduct a similar trial in the United States.