12-Month Blood Pressure Results of Catheter-Based Renal Artery Denervation for Resistant Hypertension - The SYMPLICITY HTN-3 Trial

Bakris GL, Townsend RR, Flack JM et al.,
J Am Coll Cardiol. 2015;65(13):1314-1321. doi:10.1016/j.jacc.2015.01.037

Background

The sham-controlled SYMPLICITY HTN-3 trial evaluated renal denervation (RDN) in patients with uncontrolled hypertension on a stable antihypertensive medication regimen of maximally tolerated doses of >3 medications of complementary classes, including a diuretic. Ambulatory blood pressure measurement (ABPM) was used as a pre-specified secondary endpoint. ABPM, and home and office blood pressure (BP) were measured at baseline, and at 6 months.
The primary results did not show a greater reduction in office or ambulatory systolic BP (SBP) at 6 months after RDN than after the sham procedure [1]. This paper presents office and 24-h ABPM results of SYMPLICITY HTN-3 after 1 year of follow-up in the original cohort randomised to the procedure, as well as in those who underwent RDN at 6 months, and in those not eligible to be crossed over.

Main results

• Changes in office SBP at 12 months were significantly greater than those seen at the 6-month visit in the RDN group (-15.5+24.1 vs. 18.9+25.4, P=0.025). ABPM changes were not significantly different between 6 and 12 months.
• 6-month change in office SBP in the crossover group was -17.7+23.2 mmHg (P<0.001 from baseline) and the change in 24-h SBP was -9.2+13.6 mmHg (P<0.001).
• Most people in the non-crossover group were not eligible for RDN because they did not meet the SBP minimum of 160 mmHg at 6 months (mean office SBP/DBP was 145.6+24.6/82.9+13.4 mmHg). A large change from baseline SBP was seen at 6 months (-32.9u+28.1 mmHg) and at 12 months (-21.4+19.9 mmHg).
• Safety measures were similar between 6 and 12 months in all three groups. One subject in the RDN group with an extensive history of obesity, CV disease, renal insufficiency and diabetes type 2 developed end-stage renal disease.

Conclusion

This analysis of 12 month follow-up data from the SYMPLICITY HTN-3 trial reaffirm the 6-month data of the primary and specified secondary endpoints after unblinding at 6 months. A small but significant extra drop in office BP was seen after RDN at 12 months, as compared with 6 months, but no significant reduction in ABPM. Subjects originally randomised to the sham procedure who now underwent RDN showed a similar drop in ABPM 6 months after the procedure to those who underwent RDN at the start of the trial. Renal denervation is safe, but when applied as in SYMPLICITY HTN-3, it does not clearly reduce BP more than medication.

Find this article online at JACC

References

1. Bhatt DL, Kandzari DE, O’Neill WW, et al. A controlled trial of renal denervation for resistant hypertension.New Engl JMed 2014;370:1393–401.