Renal Denervation System Shown to Decrease Blood Pressure

David Kandzari, MD

New research, presented at the 2018 EuroPCR Annual Meeting in Paris, France, has shown that renal denervation, when done in the main renal arteries and branches, can significantly reduce blood pressure (BP).

Previously, studies on the process have churned out varying results, prompting researchers led by David Kandzari, MD, the director of interventional cardiology and chief scientific officer at Piedmont Heart Institute in Atlanta, Georgia, to evaluate the 6-month safety and blood pressure response in 467 patients with hypertension post-renal denervation, compared with sham.

“Data from the SPYRAL HTN-ON MED study is important for the clinical community and for patients with hypertension as it represents a typical scenario of managing uncontrolled hypertension patients, prescribed up to three blood pressure medications,” Kandzari said in a statement. “With these new results, mirroring those of the parallel SPYRAL HTN-OFF MED trial, we have convincing evidence at 6 months showing the continued safety and efficacy of [renal denervation] in both the presence and absence of blood pressure medication.”

Eligible patients reported an office-measured systolic BP between 150-180 mm Hg and a diastolic BP of ≥90 mm Hg; a 24-hour ambulatory systolic BP between 140-170 mm Hg at second screening; and were being administered 1to 3 antihypertensive drugs at stable doses for at least 6 weeks.

In the double-blind, proof-of-concept, multicenter trial, patients were randomized to the Symplicity Spyral renal denervation system (n = 38) and sham (n = 42), with a primary endpoint of BP change from baseline, measured at 6 months. Additionally, drug surveillance was used to assess medication adherence.

Results from the first 80 patients enrolled were shown to reduce 24-hour systolic BP by —7.0 mm Hg (95% CI, –12.0 to –2.1; P = .0059) and diastolic BP by —4.3 mm Hg (95% CI, –7.8 to –0.8; P = .0174). Additionally, office systolic BP was decreased by —6.6 mm Hg (95% CI, –12.4 to –0.9; P = .0250) and diastolic by —4.2 mm Hg (95% CI, –7.7 to –0.7; P = .0190).

Compared with the sham arm, the change in BP was significantly greater in the renal denervation arm for both baseline measurements. The office differences were −6.8 mm Hg, (95% CI, −12.5 to −1.1; P = .0205) for systolic BP and −3.5 mm Hg (95% CI, −7.0 to −0.0; P = .0478) for diastolic BP. For 24-hour measurements, systolic BP was —7.4 mm Hg lower (95% CI, −12.5 to −2.3; P = .0051) and diastolic was —4.1 mm Hg lower (95% CI, −7.8 to −0.4; P = .0292).

Blood pressure changes over the 24-hour period, as measured by hourly evaluations, showed that the reduction experienced by the renal denervation arm occurred consistently throughout.

"We are encouraged by these data showing the procedure may enable a blood pressure lowering effect 24 hours a day. [Renal denervation] is essentially 'always on' even when the effect of medications may be subsiding between doses," Raymond Townsend, MD, the director of the Hypertension Program at the Hospital of the University of Pennsylvania, a professor of Medicine in the Perelman School of Medicine at the University of Pennsylvania, and co-principal investigator in the trial said in a statement. "These data also show that treatment with [renal denervation] in the main renal artery and branches with the Spyral System can help reduce blood pressure."

With the introduction of the new American College of Cardiology/American Heart Association guideline for hypertension in late 2017 increasing the number of adults with hypertension in the US by an estimated 31.3 million, the need for effective measures has almost never been greater. This is especially true considering hypertension, like many conditions, often results in poor medication adherence from patients.

Medication adherence in this study was measured at about 60%, although Kandzari and colleagues noted that it varied on an individual basis. No major adverse events were reported.

Both Townsend and Kandzari are members of the Medtronic Executive Committee that designed and oversees the SPYRAL HTN Global Clinical Program. The study, “Effect of renal denervation on blood pressure in the presence of antihypertensive drugs: 6-month efficacy and safety results from the SPYRAL HTN-ON MED proof-of-concept randomized trial,” was published in The Lancet.