Renal Nerve Denervation, Adherence, and Management of Resistant Hypertension
Authors: David A. Calhoun
Journal: Circulation (2016)

ince publication of the SYMPLICITY HTN-3 trial (Renal Denervation in Patients With Uncontrolled Hypertension) results in 2014, which reported a similar blood pressure (BP) reduction in subjects with resistant hypertension who had either renal nerve denervation (RND) or sham intervention, there has been much discussion as to whether RND truly provides antihypertensive benefit. 1 The discussion has included suggestions that RND functionally does very little, if anything, such that any associated BP reductions are placebo related; that observed benefit with RND is likely a consequence of a large regression to the mean effect in patients with high baseline BP values; and, in the case of SYMPLICITY HTN-3, inadequate nerve ablation by interventionalists inexperienced with the RND procedure resulting in reduced treatment benefit.There has also been concern that changes in medication adherence by patients participating in RND trials, in particular, immediately after having the procedure done or not, might be confounding the observed results.To explain the BP reductions in both the truly treated and sham-treated groups that occurred in SYMPLICITY HTN-3, one would have to suppose that the procedure had little effect and both patient groups were suddenly, but equally more adherent after randomization, such that the similar BP reductions were simply attributable to patients actually taking their medications; or, alternatively, that the procedure did have a true antihypertensive effect that was, however, obscured by increased medication adherence in the sham-treated patients.Because SYMPLICITY HTN-3 did not include biochemical assessment of medication adherence, such consideration has had to remain speculative.In this issue of Circulation, Azizi et al 2 provide important results relating to medication adherence and the true of effects of RND in a randomized trial format.They report no differences in drug exposure between patients with resistant hypertension participating in the DENERHTN (Renal Denervation for Hypertension) trial who had been randomly assigned either to RND with intensification of medical therapy versus intensification of medical therapy alone.The DENERHTN trial was a prospective, open-label, randomized evaluation of patients with uncontrolled resistant hypertension despite the use of a standardized regimen of indapamide, ramipril (or irbesartan), and amlodipine. 3True uncontrolled resistant hypertension was confirmed by ambulatory BP monitoring in all patients.Patients were randomly assigned to either RND with continued titration of antihypertensive medications as needed for uncontrolled BP or medication titration alone.The titration schedule was standardized and included, in order, the addition of spironolactone, bisoprolol, prazosin, and, last, rilmenidine.The primary end point was mean change in daytime systolic BP from baseline at 6 months follow-up as measured by ambulatory BP monitoring.Overall, 48 patients in the RND group and 53 control subjects completed the protocol and were included in the analysis. 3The mean change in daytime ambulatory renal Nerve denervation, adherence, and Management of resistant Hypertension