Medtronic Presents Final 3-Year Data From Symplicity HTN-1 Trial of Renal Denervation

September 3, 2013—Medtronic, Inc. (Minneapolis, MN) announced that the final 3-year results from the Symplicity HTN-1 clinical trial were presented at the European Society of Cardiology (ESC) Congress 2013 in Amsterdam, The Netherlands. Symplicity HTN-1 is investigating the safety and efficacy of the company's Symplicity renal denervation system. The results have been accepted for publication in The Lancet, according to the company.

The data were presented at the ESC meeting by the trial's Principal Investigator, Professor Henry Krum, MD, Director of the Monash Center of Cardiovascular Research and Education in Therapeutics in Melbourne, Australia.

According to the company, 88 treatment-resistant hypertension patients were available for 36-month evaluations after treatment with the Symplicity renal denervation system. These 88 patients demonstrated sustained reductions in blood pressure year-over-year with an average reduction of -32/-14 mm Hg (P < .01). Of these 88 patients, approximately 50% achieved the goal of a systolic blood pressure < 140 mm Hg despite having a mean systolic blood pressure of 169.8 mm Hg before denervation therapy. There were very few clinically significant late adverse events reported through 3 years of follow-up, noted Medtronic.

“We are pleased to find that we're seeing sustained and significant blood pressure reductions overall in all patients who reached the three year time point following their denervation procedure,” noted Prof. Krum in Medtronic's press release. “Achieving a goal of below 140 mm Hg in about half of these patients is impressive considering that these patients had very high baseline blood pressures despite being on multiple pharmaceutical agents. These were patients who were out of hypertension treatment options before they received renal denervation, so reductions of blood pressure of this magnitude may dramatically decrease their risk for stroke, heart attack, heart failure, and kidney disease in the years to come.”

Symplicity HTN-1 is a series of pilot studies at 19 centers in Australia, Europe, and the United States. The open-label studies enrolled 153 patients with treatment-resistant hypertension, defined as having a systolic blood pressure ≥ 160 mm Hg while taking ≥ 3 antihypertensive drugs at optimal dosages, including a diuretic. The patients consented to be followed for either 1, 2, or 3 years after treatment with renal denervation. Follow-up is now complete for the 88 patients who were followed to 3 years. Symplicity HTN-1 is the largest cohort of patients with the longest follow-up data for renal denervation to date.

Patients treated with renal denervation experienced consistent reductions in blood pressure regardless of advanced age, the presence of diabetes, or impaired baseline renal function. Safety follow-up between 24 and 36 months demonstrated continued stable renal function; two orthostatic hypotension events in one subject resolved with medication changes, and there was one renal artery stenosis at 24 months, possibly related to the renal denervation procedure. Adverse events due to comorbid diseases such as infection and nonrenal surgical complications were also reported.

The Symplicity system received European CE Mark approval in 2008. In the United States, the Symplicity renal denervation system is currently available for investigational use only, advised Medtronic.