Meta-analysis of randomized controlled trials of renal denervation in treatment-resistant hypertension

Objective. The blood pressure (BP)-lowering effect of renal sympathetic nervous denervation (RDN) in resistant hypertension (rHT) shows large variation among studies. Methods. We meta-analyzed summary statistics of randomized clinical trials on RDN in rHT. For continuous outcomes, we assessed heterogeneity by Cochran's Q test and used random-effect models weighted for the inverse of the variance. We assessed safety by assessing the risk of major adverse events from stratified contingency tables. Results. Of 5652 patients screened in seven trials, 985 (17.4%) qualified and were randomized to control (n=397) or RDN with SYMPLICITY (TM) catheters (n=588). Follow-up was 6 months. In both control and RDN patients, antihypertensive treatment was continued or optimized. At enrolment, age averaged 58.1 years, systolic/diastolic office and 24 h BP 168.5/93.3 mmHg and 151.8/86.1 mmHg, respectively, and estimated glomerular filtration rate (eGFR) 79.3 ml/min/1.73 m(2). For BP outcomes, there was heterogeneity among trials. Pooled effects (control minus RDN) were -4.9/-3.5 mmHg (95% confidence interval, -20.9 to 11.1/-8.9 to 1.9) for office BP, -2.8/-1.5 mmHg (-6.5 to 0.8/-3.3 to 0.4) for 24 h BP and 0.81 ml/min/1.73 m(2) (-1.69 to 3.30) for eGFR. Removing one trial at a time produced confirmatory results. Adverse events occurred in 7.4% and 9.9% of control and RDN patients, respectively (p=0.24). Conclusion. In selected rHT patients maintained on antihypertensive drugs, RDN with the SYMPLICITY systems does not significantly decrease BP but is safe. Future trials with next-generation catheters should aim at identifying responders in patients with evidence of sympathetic nervous overactivity.