Statistical Analysis Supports Renal Denervation for Treating Hypertension Across Age Groups

May 9, 2013—The Society of Cardiovascular Angiography and Interventions (SCAI) announced the presentation of data suggesting that catheter-based renal denervation is projected to improve blood pressure and substantially reduce the incidence of major cardiovascular events in patients whose high blood pressure has not been sufficiently lowered with medications. Lead Investigator Jan Pietzsch, PhD, presented the findings at the SCAI 2013 scientific sessions in Orlando, Florida.

According to the SCAI announcement, the predictions are based on a statistical extrapolation from clinical trial data and were consistent across age groups and event categories, including the risk of heart attack and stroke. The study investigators employed a mathematical model to analyze data from the Symplicity HTN-2 randomized, controlled trial to project the clinical benefits during a 10-year period for patients who are 40, 55, and 70 years of age. The statistical analysis shows that patients in all of the age groups stand to experience clinical benefits from renal denervation. Among the projected benefits would be significant reductions in the risks of heart attack, stroke, and kidney failure.

As summarized in the SCAI press release, all of the study's relative and absolute risk predictions were applicable for a 10-year period. The results predicted a reduction in pretreatment systolic blood pressure from 165 to 135 mm Hg in the low range and from 190 to 150 mm Hg in the high range, representing the minimum and maximum reported values for each clinical event type. The youngest group (age 40) showed the largest relative reduction in cardiovascular risk, whereas the oldest cohort (age 70) was projected to experience the most substantial absolute event reduction.

Additionally, the investigators found that the model projected significant drops in cardiovascular events across each of the three age groups and the two theoretical blood pressures (40/165 mm Hg and 70/190 mm Hg) at the time of treatment. For example, a > 40% reduced risk of heart attack was projected for patients with systolic blood pressures > 190 mm Hg undergoing catheter-based renal denervation at 40 years of age and an 8% absolute reduction of risk for all coronary heart disease for those with the same blood pressure undergoing interventional renal denervation at 70 years of age.

“To predict event reductions and understand cardiovascular risk for a range of patient cohorts treated with renal denervation, we looked not only at data from a specific randomized trial, but also at extrapolated data for different age groups and at relatively low hypertension and high hypertension statistics,” commented Dr. Pietzsch in the SCAI press release. “Pretty much across the board, there are clinically meaningful reductions that we project both in terms of absolute and relative reductions of clinical events in all three age groups.” Dr. Pietzsch stressed that, “Clinical trials will need to be completed to validate these modeled projections.”

Dr. Pietzsch is the CEO of Wing Tech Inc. (Menlo Park, CA), a health economics consulting firm that advises Medtronic, Inc. (Minneapolis, MN), which manufactures the Symplicity renal denervation system. He is also a consulting associate professor at Stanford University.

The SCAI press release noted that renal denervation, which has previously been found to reduce drug-resistant hypertension by interrupting sympathetic nerve signals from the kidneys, has been approved in Europe as a treatment for hypertension. In the United States, it is an investigational procedure. Medtronic's Symplicity system is currently under joint consideration by the US Food and Drug Administration and the Centers for Medicare & Medicaid Services.