Revisiting Renal Denervation

When compared with the RDN group, the sham control group lowered blood pressure to almost the same degree, whether measured in the office or by ambulatory blood pressure monitoring, in drug-resistant hypertensive patients.6 This trial's disappointing results cast considerable doubt on the value of this approach in managing this difficult patient population.7 An editorial in the British Medical Journal that appeared shortly after the results of HTN-3 were announced captured the issue of bias in the studies leading up to HTN-3,8 and we returned to the drawing board and began an in-depth postmortem examination of the results. After months of interaction with multiple experts in hypertension, cardiology, and biostatistics, several areas of trial design were identified that were believed to have contributed to the disappointing results.9 This was also an opportunity to lay to rest the question of whether RDN really does anything to lower the blood pressure in the untreated state (no antihypertensive medication), and whether an effect on blood pressure (if present) was evident in the presence of antihypertensive medication. In this issue of the Proceedings, an update on the field is presented that incorporated the results of 12 randomized clinical trials of RDN undertaken with either radiofrequency ablation or by ultrasound presented by Cheng et al.13 The authors note that the RDN procedure, compared with the control group, is associated with an ambulatory systolic BP reduction of 4 mm Hg over 24 hours, and an in-office systolic BP reduction of 9 mm Hg, after approximately 5 months of follow-up. At this time, there is no way known to predict accurately who will or will not respond to kidney artery nerve ablation. [...]after RDN is performed it takes a minimum of 2 (ultrasound energy) or 3 (radiofrequency energy) months to see a denervation reduction in systolic BP "signal."