November 3, 2026Circulation Cardiovascular Interventions
Effectiveness of Radiofrequency Renal Denervation in the United States: Six-Month Primary End Point Results From the SPYRAL AFFIRM Study
David E. KandzariKazuomi KarioMichael A. WeberRaymond R. TownsendRoland E. SchmiederMichael BöhmKonstantinos TsioufisRobert StolerDavid P. LeeFrank NavettaBarry BertoletSrinivasa PotluriShukri DavidDebbie L. CohenTe‐Hsin LungKelsey AndersonJulie CarvelliFelix Mahfoudon behalf of the SPYRAL AFFIRM Study Investigators
Key result
Renal denervation lowers 6-month office systolic BP by ~18 mm Hg from baseline.
- MD -18.2 mm Hg
- P<0.001
- n=594
Why the study?
Although radiofrequency renal denervation is a guideline-recommended therapy for uncontrolled hypertension, postapproval data assessing its efficacy and safety using the Symplicity Spyral catheter in a broader US population were needed.
Does radiofrequency renal denervation using the Symplicity Spyral catheter reduce office systolic blood pressure at 6 months compared to a prespecified performance goal in US patients with uncontrolled hypertension?
Study Design
Type
Cohort (n=594)
Multicenter
Yes
Structured PICO
Does radiofrequency renal denervation using the Symplicity Spyral catheter reduce office systolic blood pressure at 6 months compared to a prespecified performance goal in US patients with uncontrolled hypertension?
P
Population
594 US adults with uncontrolled hypertension (mean age 57 years, 45% female) treated across 73 clinical sites and followed for 6 months.
I
Intervention
Radiofrequency renal denervation (RDN) using the Symplicity Spyral catheter on a background of an average of 3.6±2.0 antihypertensive medications.
C
Comparator
Prespecified performance goal of −6.0 mm Hg for 6-month change in office systolic BP from baseline (single-arm study with no concurrent control arm).
O
Outcome
6-month change in office systolic blood pressure from baseline compared with a prespecified performance goal (−6.0 mm Hg).surrogate
Main Result
Mean Difference: -18.2
Absolute Event Rate: -18.2% vs -6%
p-value: p=<0.001
Limitations
- Single-arm study design
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Key expert perspectives
Captured external expert commentary on this paper, strongest first. Original sources are linked where available.
“The blood pressure reductions achieved with RDN in the AFFIRM study are transformative. In fact, they are within the range associated with a greater than 20% reduction in major adverse cardiovascular events, underscoring the clinical significance of these results.”
“We’re observing meaningful, significant reductions in systolic blood pressure [and] diastolic blood pressure, but also across all different measures of how we check blood pressure, meaning office, home, [and] ambulatory criteria, so quite a concordance.”
“What makes this study interesting... is the inclusion of a more complex patient profile, including patients who come to offices on a daily basis. This means patients who were not typically enrolled in clinical trials.”
Implication
In a real-world US postapproval setting, radiofrequency renal denervation demonstrated significant 6-month reductions in office, home, and 24-hour ambulatory blood pressure with uncommon adverse events.
Abstract
BACKGROUND: Radiofrequency renal denervation (RDN) is a guideline-recommended therapy for uncontrolled hypertension. SPYRAL AFFIRM is a single-arm, postapproval study assessing the efficacy and safety of radiofrequency RDN using the Symplicity Spyral catheter. We report the 6-month primary end point results in the SPYRAL AFFIRM US population. METHODS: Enrolled patients had an office systolic/diastolic blood pressure (BP) ≥140/90 mm Hg and a home systolic BP ≥135 mm Hg. Patients with type 1 diabetes, poorly controlled type 2 diabetes (HbA1c >8.0%), or an estimated glomerular filtration rate <45 mL/min per 1.73 m 2 were excluded. The primary end point was the 6-month change in office systolic BP from baseline compared with a prespecified performance goal (−6.0 mm Hg). RESULTS: Among 594 patients treated in the AFFIRM study from 73 US clinical sites, baseline clinical characteristics included: mean (±SD) age, 57±12 years; female, 45%; African American, 27%; Hispanic, 11%; type 2 diabetes, 19%; and mean estimated glomerular filtration rate, 79±20 mL/min per 1.73m 2 . Baseline systolic/diastolic office, home, and 24-hour ambulatory BP (mm Hg) were 169±21/106±13, 158±17/101±13, and 151±18/96±13, respectively. Patients were prescribed an average of 3.6±2.0 antihypertensive medications at baseline that remained unchanged through 6 months. Six months after RDN, the change in systolic BP (mm Hg) was −18.2±22.0, −9.4±13.8, and −9.7±16.8 for office, home, and 24-hour ambulatory measures, respectively ( P <0.001 compared with baseline). Adverse clinical events through 6 months were uncommon. CONCLUSIONS: In this US postapproval study, the primary end point was met with significant BP reductions following radiofrequency RDN consistent across different measures. In a broader patient population with uncontrolled hypertension, these results reaffirm the safety and efficacy of radiofrequency RDN. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT05198674.
Coverage & sources
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Cite This Study
Kandzari et al. (2026) conducted a cohort in Uncontrolled hypertension (n=594). Radiofrequency renal denervation using the Symplicity Spyral catheter vs. Prespecified performance goal (−6.0 mm Hg) / baseline was evaluated on 6-month change in office systolic blood pressure from baseline (MD -18.2 mm Hg, p=<0.001). Radiofrequency renal denervation reduced 6-month office systolic BP by −18.2±22.0 mm Hg (P<0.001 vs baseline), meeting the −6.0 mm Hg performance goal.