Ablating Renal Nerves Reduces Resistant Hypertension

Researchers at Ohio State University (OSU; Columbus, USA), the Baker IDI Heart and Diabetes Institute (Melbourne, Australia), and other institutions worldwide participating in the nonrandomized Symplicity HTN-1 study reported the three-year results of the study, involving 153 with resistant hypertension--defined as SPB greater than 160 mm Hg, the use of three or more anti-hypertensive medications, and an estimated glomerular filtration rate of 45 mL/minute or greater.

The researchers reported that despite not all patients initially responding favorably to renal denervation, the percentage of responders increased over time. At one month, 69% of 143 patients responded; at 12 months, it was 79% of 130 patients; at two years, it was 90% of 59 patients; and at three years, 100% of 24 patients had responded. Of the initial nonresponders, all eight patients who were followed for three years eventually became responders. The researchers arbitrarily chose a 10 mm Hg or higher reduction in SBP as the cutoff point that defined responders. The results of the study were presented at the American College of Cardiology (ACC) meeting, held during March 2012 in Chicago (IL, USA).

“The procedure appears safe, with relatively few complications, including no deaths related to the procedure; the magnitude of clinical response is significant and sustained through three years,” concluded coauthor Paul Sobotka, MD, of the OSU, and colleagues. “No response at six months in blood pressure reduction does not predict failure at 12 months.”

The Symplicity renal denervation system, a product of Medtronic (Fridley, MN, USA), consists of a flexible catheter and proprietary generator. In an endovascular procedure, similar to an angioplasty, the physician inserts the small, flexible catheter into the femoral artery in the upper thigh and threads it into the renal artery. Once the catheter tip is in place within the renal artery, the Symplicity generator is activated to deliver controlled, low-power RF energy to deactivate the surrounding renal nerves. This, in turn, reduces hyper-activation of the sympathetic nervous system, which is an established contributor to chronic hypertension.

Related Links:
Ohio State University
Baker IDI Heart and Diabetes Institute
Medtronic