Key result
Renal denervation reduces 24-hour ambulatory systolic BP by ~5 mm Hg vs. sham outside the US.
Why the study?
Despite significant office and nighttime BP reductions with RDN versus sham control, 24-hour BP reductions were similar, prompting comparison of antihypertensive medication and BP changes among prespecified subpopulations.
Does renal denervation reduce blood pressure in patients with uncontrolled hypertension on 1-3 antihypertensive medications across different geographic and racial subgroups?
RCT (n=337)
Double-blind
Randomized
Yes
Does renal denervation reduce blood pressure in patients with uncontrolled hypertension on 1-3 antihypertensive medications across different geographic and racial subgroups?
Mean Difference: -4.8 (95% CI -7.6–-2)
Absolute Event Rate: -7.4% vs -2.6%
p-value: p=0.0010
Unrecognized changes in antihypertensive medication burden, particularly among US sham control patients, likely confounded the blood pressure-lowering effects of renal denervation in the SPYRAL HTN-ON MED trial.
Medication changes in the US cohort likely masked renal denervation efficacy; challenges overall trial conclusions while extending support for its BP-lowering effect outside the US.
BACKGROUND: The SPYRAL HTN-ON MED (Global Clinical Study of Renal Denervation With the Symplicity Spyral Multi-electrode Renal Denervation System in Patients With Uncontrolled Hypertension in the Absence of Antihypertensive Medications)trial showed significant office and nighttime systolic blood pressure (BP) reductions in patients with hypertension following renal denervation (RDN) compared with sham-control patients, despite similar 24-hour BP reductions. We compared antihypertensive medication and BP changes among prespecified subpopulations. METHODS: The multicenter, randomized, sham-controlled, blinded SPYRAL HTN-ON MED trial (n=337) evaluated BP changes after RDN compared with a sham procedure in patients with hypertension prescribed 1 to 3 antihypertensive drugs. Most patients (n=187; 54%) were enrolled outside the United States, while 156 (46%) US patients were enrolled, including 60 (18%) Black Americans. RESULTS: Changes in detected antihypertensive drugs were similar between RDN and sham group patients in the outside US cohort, while drug increases were significantly more common in the US sham group compared with the RDN group. Patients from outside the United States showed significant reductions in office and 24-hour mean systolic BP at 6 months compared with the sham group, whereas BP changes were similar between RDN and sham in the US cohort. Within the US patient cohort, Black Americans in the sham control group had significant increases in medication burden from baseline through 6 months ( P =0.003) but not in the RDN group ( P =0.44). CONCLUSIONS: Patients enrolled outside the United States had minimal antihypertensive medication changes between treatment groups and had significant office and 24-hour BP reductions compared with the sham group. Increased antihypertensive drug burden in the US sham cohort, especially among Black Americans, may have diluted the treatment effect in the combined trial population. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02439775.
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Townsend et al. (2024) conducted an RCT in Uncontrolled hypertension (n=337). Renal denervation vs. Sham procedure was evaluated on Change in 24-hour ambulatory systolic BP at 6 months (outside US cohort) (MD -4.8 mm Hg, 95% CI -7.6 to -2.0, p=0.0010). Renal denervation significantly reduced 24-hour ambulatory systolic blood pressure by 4.8 mm Hg compared to sham control in patients outside the United States, whereas medication changes diluted the effect in the US cohort.
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