Catheter-based renal sympathetic denervation is effective in reducing office and ambulatory blood pressure in patients with resistant hypertension

Renal denervation, adjusted drugs, or combined therapy for resistant hypertension: A meta-regression

The objective of this study is to systematically evaluate the efficacy of renal denervation (RD), adjusted drugs, or combined therapy for resistant hypertension (RH) through a systematic review and meta-analysis of controlled studies.Publications were comprehensively searched. Studies that investigated the effects of RD and/or adjusted drugs in lowering blood pressure (BP) were included. After quality assessment and data extraction, subgroup analyzes were first performed according to blinding method. Meta-regression and inverted funnel plots were also conducted.A total of 13 studies containing 1604 RH patients were included. Compared with control, the meta-analysis showed that RD significantly reduced office-based BP and ambulatory BP in 6 months in the unblinded studies, while no significant difference was found in the blinded studies. Meta-regression demonstrated the significant influence of blinding method on BP reduction, and further analysis revealed a significant BP reduction compared with baseline even in the control arm of blinded studies. RD had similar effects compared with adjusted drugs, and combined therapy seemed to further reduce the level of BP.The efficacy of RD was different between blinded and unblinded studies, and our data revealed a significant BP-lowering effect in the control arm of blinded studies, which was helpful to explain this finding. Furthermore, RD seemed to be equivalent to adjusted drugs, and also we suggested a potential advantage of combined therapy of RD and adjusted drugs compared with monotherapy for RH. However, more studies are warranted to better address the issue.

Renal denervation

PURPOSE OF REVIEW

Renal denervation (RDN) has, within recent years, been suggested as a novel treatment option for patients with resistant hypertension. This review summarizes the current knowledge on this procedure as well as limitations and questions that remain to be answered.

RECENT FINDINGS

The Symplicity HTN-1 (2009) and HTN-2 (2010) studies re-introduced an old treatment approach for resistant hypertension and showed that catheter-based RDN was feasible and resulted in substantial blood pressure (BP) reductions. However, they also raised questions of durability of BP reduction, correct patient selection, anatomical and physiological effects of RDN as well as possible beneficial effects on other diseases with increased sympathetic activity. The long awaited Symplicity HTN-3 (2014) results illustrated that the RDN group and the sham-group had similar reductions in BP.

SUMMARY

Initial studies demonstrated that RDN in patients with resistant hypertension was both feasible and safe and indicated that RDN may lead to impressive reductions in BP. However, recent controlled studies question the BP lowering effect of RDN treatment. Large-scale registry data still supports the favorable BP reducing effect of RDN. We suggest that, in the near future, RDN should not be performed outside clinical studies. The degree of denervation between individual operators and between different catheters and techniques used should be clarified. The major challenge ahead is to identify which patients could benefit from RDN, to clarify the lack of an immediate procedural success parameter, and to establish further documentation of overall effect of treatment such as long-term cardiovascular morbidity and mortality.

Meta-analysis of the effect of renal denervation on blood pressure and pulse pressure in patients with resistant systemic hypertension

Data comparing the effect of renal denervation (RD) with those of maximal medical therapy (MMT) have shown conflicting results. Also, effect of RD on pulse pressure (PP) has not been evaluated. The aim of this meta-analysis was to compare the effect of RD with that of MMT on blood pressure (BP) and PP at 6-month follow-up in patients with resistant hypertension. Randomized controlled trials and nonrandomized controlled trials reporting systolic BP, diastolic BP, and PP results in RD and MMT groups at 6-month follow-up in patients with resistant hypertension were systematically reviewed, and eligible citations were pooled using a random-effects model. Five studies (3 randomized controlled trials, 2 nonrandomized controlled trials, n = 800) met the inclusion criteria. In the pooled analysis, RD was associated with a significant decrease in systolic BP (weighted mean difference -19.4 mm Hg, 95% confidence interval -32.8 to -5.9, p = 0.005), diastolic BP (weighted mean difference -6.4 mm Hg, 95% confidence interval -10.7 to -2.0 mm Hg, p = 0.004), and PP (weighted mean difference -12.7 mm Hg, 95% confidence interval -22.3 to -3.1 mm Hg, p = 0.009) compared with MMT at 6-month follow-up. Sensitivity analysis limited to randomized controlled trials showed a borderline significant difference in lowering systolic BP, a significant difference in lowering diastolic BP, and a nonsignificant difference in lowering PP when RD was compared with MMT. In conclusion, this meta-analysis shows that RD is superior to MMT in lowering BP, but heterogeneity among study populations in this pooled sample is high, and further data are needed to better compare these treatment strategies.