More Promising Results For Renal Denervation: Sustained BP Reduction At 18 Months

In short

It’s European Society of Cardiology Congress time, so expect a flurry of cardiology news items. First to take advantage is Medtronic, Inc. which has announced new results from Symplicity™  HTN-2 the only randomised clinical trial investigating safety and efficacy of renal denervation.

18-month data presented for the first time at the European Society of Cardiology (ESC) Congress 2012 showed the Symplicity system continues to provide superior and sustained blood pressure reduction in patients with treatment-resistant hypertension.

The safety of renal denervation with the Symplicity system was also maintained at 18 months, with no device-related serious adverse events and no newly reported vascular complications from 12-18 months.

Background

Renal denervation therapy is a minimally invasive, catheter-based procedure that modulates the output of nerves that lie within the renal artery wall and lead into and out of the kidneys. These nerves are part of the sympathetic nervous system, which affects the major organs that are responsible for regulating blood pressure: the brain, the heart, the kidneys and the blood vessels.

The Symplicity system’s catheter and proprietary generator and algorithms were carefully and specifically developed through years of clinical experience to enhance the safety and effectiveness of the renal denervation procedure. The Symplicity renal denervation system has been successfully used for five years to treat nearly 5,000 patients with treatment-resistant hypertension worldwide.

The study

The Symplicity HTN-2 trial is an international, multi-centre, prospective, randomised, controlled study of the safety and effectiveness of renal denervation in patients with treatment-resistant hypertension. One hundred and six (106) patients were randomly allocated in a one-to-one ratio to undergo renal denervation with previous treatment or to maintain previous treatment alone (control group) at 24 participating centers. At baseline, the randomised treatment and control patients had similar high blood pressures: 178/97 mm Hg and 178/98 mm Hg, respectively, despite both receiving an average daily regimen of five antihypertensive medications. Patients in the control arm of the study were offered renal denervation following assessment of the trial’s primary endpoint at six months following randomisation.

43 patients initially randomised to renal denervation with the Symplicity system had an average blood pressure reduction of -32/-12 mm Hg from baseline [p<0.01] at 18 months. Thirty-one control patients who received renal denervation following the six-month primary endpoint (crossover group) had an average blood pressure reduction of -28/-11 mm Hg [p<0.01] at 18 months. These 18-month average blood pressure reductions are maintained for both groups from 12-month follow-up (-28/-10 mm Hg [p<0.01] for the initial treatment group; -24/-10 mm Hg [p<0.01] for the crossover group).

The average number of medications for patients in this trial did not change from baseline to 18-months. At 18 months, pulse pressure improved significantly for patients in this analysis following treatment with the Symplicity system (-20 mm Hg from baseline for the initial treatment group [p<0.01]; and -18 mm Hg from baseline for the crossover group [p<0.01]).

Investigator comments

“We continue to see significant and sustained improvement in blood pressure levels for patients who receive renal denervation with the Symplicity system, as these 18-month average blood pressure reductions are consistent with the 12-month follow-up data for both groups,” said Murray Esler, M.B.B.S., Ph.D., principal investigator of the Symplicity HTN-2 trial and associate director of the Baker IDI Heart and Diabetes Institute of Melbourne, Australia. “This is encouraging since patients with treatment-resistant hypertension are often taking more than three antihypertensive medications and still are unable to control their blood pressure, which can put them at risk for various cardiovascular events such as heart attack, stroke or heart failure.”

Regulatory status

The Symplicity renal denervation system was launched commercially in April 2010 and is currently available in parts of Europe, Asia, Africa, Australia and the Americas.

The Symplicity renal denervation system is not approved by the U.S. Food and Drug Administration (FDA) for commercial distribution in the United States.

The FDA granted Medtronic approval for the protocol for SYMPLICITY HTN-3, the company’s U.S. clinical trial of the Symplicity renal denervation system for treatment resistant hypertension in August 2011. Consequently the system is only available in the United States for investigational use.

References

i Egan, Brent M., et al. “Uncontrolled and Apparent Treatment Resistant Hypertension in the United States, 1988-2008.” Circulation 124. 9 (2011): 1046-1058.

ii Doumas, Michael, et al. “Benefits from Treatment and Control of Patients with Resistant Hypertension.” International Journal of Hypertension 2011 (2011) Article ID 318549, 8 pages, 2011. doi:10.4061/2011/318549.
Symplicity is a trademark of Medtronic Inc. and is registered in one or more countries of the world.

Source: Medtronic Inc.