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

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