Renal Denervation After Symplicity HTN-3 - Back to Basics. Review of the Evidence.

Renal sympathetic denervation (RDN) has been proposed as a new treatment modality in patients with apparent treatment resistant hypertension, a condition defined as office blood pressure elevation despite prescription of at least three antihypertensive drugs including a diuretic. However, the impressive fall in blood pressure reported after RDN in Symplicity HTN-2, the first randomised study, and multiple observational studies has not been confirmed in the US sham-controlled trial Symplicity HTN-3 and four subsequent prospective randomised studies, all published or presented in 2014. The blood pressure reduction documented in earlier studies may be largely due to non-specific effects such as improvement of drug adherence in initially poorly adherent patients (Hawthorne effect), placebo effect and regression to the mean. The overall blood pressure lowering effect of RDN seems rather limited and the characteristics of true responders remain largely unknown. Accordingly, RDN is not ready for clinical practice. In most patients with apparent drug-resistant hypertension, drug monitoring and subsequent improvement of drug adherence may prove more effective and cost-beneficial to achieve blood pressure control. In the meantime, research should aim at identifying characteristics of those few patients adherent to drug treatment and with true resistant hypertension who may respond to RDN.