Renal denervation: A safe, effective, and long-lasting blood pressure-lowering therapy.

Abstract

In The Journal of Clinical Hypertension, Tino Naduvathumuriyil and colleagues report the results of their single-center registry on the effects of renal denervation (RDN) in resistant hypertension patients. They report that a total of 50 resistant hypertension patients underwent RDN using three different systems. The data from their registry showed that office blood pressure (BP) reductions following RDN were sustained throughout the follow-up periods of up to 3 years. Mean office BP was reduced from 170.6/93.4 mm Hg at baseline to 144.2/84.6 mm Hg at 36 months. Mean changes in office systolic and diastolic BP after 36 months were −26.4 and −8.8 mm Hg (95% CI: −34.6 to −18.2 and −13.5 to −4.2 mm Hg, n = 28), respectively. Patients at the very highest BP level—greater than 180 mm Hg systolic at baseline—appeared to benefit the most from the procedure at three years. Based on office BP, 100% and 82% of patients with grade 3 hypertension were responders at 24 and 36 months, respectively. Additionally, the proportion of patients with an office systolic BP ≥ 180 mm Hg dropped from 30% at baseline to 7.4% at 3 years. Although plasma creatinine increased from 90.6 μmol/L (95% CI: 82.1-99.0 μmol/L) at baseline to 102.1 μmol/L (95% CI: 95.8-108.3 μmol/L) at 36 months (P = .007), no long-term safety concerns were observed following the RDN procedure. The study is an important evidence around RDN as a safe, effective, and long-lasting BP-lowering therapy. The Global SYMPLICITY Registry is the largest study documenting the long-term safety and effectiveness of the Medtronic renal denervation systems in a real-world setting in patients with uncontrolled hypertension.1 This single-center study, as a useful supplement to the Global SYMPLICITY Registry, reconfirmed the long-term efficacy of lowering blood pressure in RDN. The recently published randomized, sham-controlled SPYRAL HTN-OFF MED (Efficacy of catheter-based renal denervation in the absence of antihypertensive medications [SPYRAL HTN-OFF MED Pivotal]: a multicentre, randomised, sham-controlled trial)2 and (Catheter-based renal denervation in patients with uncontrolled hypertension in the absence of antihypertensive medications [SPYRAL HTN-OFF MED]: a randomised, sham-controlled, proof-of-concept trial),3 SPYRAL HTN-ON MED (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 randomised trial),4 and RADIANCE SOLO (Endovascular ultrasound renal denervation to treat hypertension [RADIANCE-HTN SOLO]: a multicentre, international, single-blind, randomised, sham-controlled trial)5 trials documented significant and consistent reductions in both office and ambulatory BP in patients with and without concomitant antihypertensive medication, while results are short term. Although the sample size is relatively small, the encouraging findings of this single-center registry support to the clinical application of RDN, a legitimate antihypertensive strategy, for uncontrolled hypertension. This single-center registry showed a substantial reduction in office BP after RDN using 3 different catheter-based radiofrequency ablation systems: the Symplicity RDN system from Medtronic, the EnligHTN RDN system from St. Jude Medical/Abbott, and the Vessix RDN system from Boston Scientific. This first comparison of 3 different radiofrequency ablation RDN systems reveals novel findings. Although the average BP reductions were modest and the number of patients was small, head-to-head comparison showed an advantage for Vessix RDN system perhaps because of the more complete renal nerve ablation. At present, there are a variety of RDN devices with different technologies, but different devices should have different effects. Both radiofrequency and ultrasound endovascular RDN systems have proven clinical efficacy for the treatment of hypertension. The Radiosound-HTN comparative trial has shown that RDN using endovascular ultrasound afforded superior reduction in ambulatory systolic BP in comparison with radiofrequency ablation system.6 Questions that remain open and require further evidence in future studies relate to the long-term safety and efficacy of both the radiofrequency ablation devices and that of other devices with different technologies in larger cohorts. A head-to-head comparison may be useful to determine the potential superiority of all the devices. Selection of suitable patients for RDN therapy is the key to the success of RDN. The ultimate litmus test is to identify responders and nonresponders to RDN therapy. The problem remains unresolved. In this small sample study, patients with grade 3 or higher hypertension had a better response, while the BP response was variable. Although more patients demonstrated BP reduction with RDN than with the sham procedure, there were changes seen in either direction for both groups in SPYRAL HTN-OFF MED, SPYRAL HTN-ON MED, and RADIANCE SOLO trials. In any case, following the positive SPYRAL HTN-OFF MED Pivotal data, these new data provide additional evidence on the safety and efficacy of RDN to help manage uncontrolled hypertension, with study patients experiencing meaningful blood pressure reductions out to several years. None disclaimers.