Renal Sympathetic Denervation Using an Irrigated Radiofrequency Ablation Catheter for the Management of Drug-Resistant Hypertension

Objectives This study sought to assess whether renal sympathetic denervation (RSDN) can be achieved using an off-the-shelf saline-irrigated radiofrequency ablation (RFA) catheter typically employed for cardiac tissue ablation. Background RSDN using a specialized solid-tip RFA catheter has recently been demonstrated to safely reduce systemic blood pressure in patients with refractory hypertension. For cardiac tissue ablation, RFA technology has evolved from nonirrigated to saline-irrigated ablation electrodes to improve both safety and effectiveness. Methods Ten patients with resistant hypertension underwent renal angiography, followed by bilateral RSDN with a saline-irrigated RFA catheter. Ambulatory blood pressure recordings (24 h) were obtained at baseline, 1, 3, and 6 months after the procedure. Repeat renal angiography was performed during follow-up to assess for arterial stenosis or aneurysm. In 5 patients, pre- and post-procedural serum measures of renal function and sympathetic activity were obtained: aldosterone; metanephrine; normetanephrine; plasma renin activity; and creatinine. Results Over a 6-month period: 1) the systolic/diastolic blood pressure decreased by -21/-11 mm Hg; 2) all patients experienced a decrease in systolic blood pressure of at least 10 mm Hg (range 10 to 40 mm Hg); 3) there was no evidence of renal artery stenosis or aneurysm at repeat angiography; and 4) there was a significant decrease in metanephrine (-12 +/- 4, p = 0.003), normetanephrine (-18 +/- 4, p = 0.0008), and aldosterone levels (-60 +/- 33 ng/l, p = 0.02) at 3 months. There was no significant change in plasma renin activity (-0.2 mg/l/hod, p = 0.4). There was no significant change in serum creatinine (-1 mmol/l, p = 0.4). Conclusions These data provide the proof-of-principle that RSDN can be performed using an off-the-shelf saline-irrigated RFA catheter. (J Am Coll Cardiol Intv 2012;5:758-65) (C) 2012 by the American College of Cardiology Foundation