Renal denervation reduces BP in hypertensive patients in absence of medications
Catheter-based Renal Denervation In The Absence Of Antihypertensive Medications: Primary Results From The SPYRAL HTN-OFF MED Pivotal Trial
Presented at ACC.20 by Prof. Michael Böhm, MD, PhD (Homburg, Germany)
Introduction and methods
Renal denervation (RDN) targets renal artery nerves in order to reduce sympathetic drive and lower blood pressure (BP). The SPYRAL HTN-OFF MED Pivotal Trial enrolled patients with hypertension (office systolic blood pressure (SBP) ≥ 150 mmHg and <180 mmHg, office diastolic blood pressure ≥90 mmHg and mean 24-hour SBP ≥140 mmHg and <170 mmHg using ambulatory blood pressure monitoring [ABPM]) and who were not on hypertension medication or had discontinued therapy for at least 3 weeks before enrollment.
Before randomization, office BP and 24h SBP were measured at baseline and patients were tested on the absence of drugs in the urine. Patients were randomized to either RDN (n=162) or sham control (n=164). After a follow-up of three months office BP and 24h SBP were measured and drug testing was repeated.
The primary endpoint was change in 24h SBP and the secondary endpoint was change in office SBP, both at 3 months.
- After three months, 24h SBP was changed by -4.7 mmHg in the RND group and in the sham control group this was -0.6 mmHg. For office SBP, the change was -9.2 mmHg in de RND group and -2.5 mmHg in the control group. Bayesian probability analysis showed a difference between groups of 3.9 mmHg for 24-hour SBP and 6.5 mmHg for office SBP. There was a >99.9% probability that RDN was superior to the sham control for both the primary and secondary endpoint.
- SBP was consistently reduced during nighttime, morning and daytime with RDN (P<0.001), which was not the case in the sham control group.
- Safety results after 1 month showed no adverse events. After 3 months, 1 (0.6%) hospitalization for hypertensive crisis or emergency had occurred in the RDN group and 1 (0.6%) major bleeding had occurred in the sham control group.
This trial showed that RDN lowers 24h SBP and office SBP compared to sham control in uncontrolled hypertensive patients in the absence of medications. 24h SBP curves showed consistent BP reduction over 24 hours in the RDN group. The follow-up study SPYRAL HTN – ON MED, in which this procedure will be tested in patients who are on hypertension medications, is currently enrolling.
The discussant Dhanunjaya Lakkireddy (Overland Park, KS, USA) pointed out that in the past there has been a substantial amount of conflicting data, confusion and high complication rates in trials investigating renal denervation. In this trial, patients were off medications, which was different compared to previous trials, to prevent confusion about the impact of medications on outcomes. Furthermore, it was a sham-controlled trial, and there is an impressive lack of complications. The reductions in BP that were observed in this trial are reasonably impressive for an antihypertensive study. However, the reductions in BP are not enough to make this a stand-alone therapy, according to Lakkireddy. Adding RDN on top of hypertensive medications could potentially be a reasonable strategy, which will be investigated in the follow-up study.
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