Renal denervation and blood pressure reduction in resistant hypertension: a systematic review and meta-analysis

The objective of this study is to evaluate the efficacy and safety of renal denervation in patients with resistant hypertension.

We searched MEDLINE and EMBASE for studies that evaluated the use of catheter-based renal sympathetic denervation compared to a control group and reported blood pressure results at follow-up. Data was extracted from relevant studies and pooled estimates for blood pressure were determined using the inverse variance method for meta-analysis with mean difference.

We identified 12 studies (three randomised controlled trials (n=688), eight prospective observational studies (n=478) and one observational study with matched controls (n=310)). Data from SYMPLICITY HTN-3, the only high-quality blinded randomised control trial suggests that there is no significant difference in change in systolic (-2.30 95% CI -6.90 to 2.30 mm Hg) or diastolic (-1.96 95% CI -4.98 to 1.06 mm Hg) blood pressure at 6 months. The pooled data from two unblinded trials of lower quality showed significant reduction in change in systolic (-27.36 95% CI -37.08 to -24.61 mm Hg) and diastolic blood pressure (-9.62 95% CI -14.51 to -4.72 mm Hg). In terms of safety, SYMPLICITY HTN-3 found no significant differences between treatment and control group in terms of death, myocardial infarction, new onset renal disease, stroke and hypertensive emergencies.

In conclusion, while poor quality unblinded studies provide evidence that renal denervation using catheter-based systems is effective in reducing systolic and diastolic blood pressure in resistant hypertension, the largest randomised controlled trial to date (SYMPLICITY HTN-3) failed to demonstrate any benefit.