Impact of sham procedure on blood pressure levels in patients with uncontrolled hypertension: A systematic review and meta-analysis of renal denervation trials

Objective: Renal denervation (RDN) has been studied extensively during the last decade. Its role in the management of resistant hypertension has been placed at the epicenter after the conduction of the second-generation trials. The impact of sham procedure however remains undetermined Design and method: PubMed and CENTRAL, along with grey literature sources, were searched from their inception to May 2019 for randomized, shamcontrolled trials primarily evaluating the efficacy and safety of RDN on the management of hypertension, irrespective of study blinding, setting and sample size We extracted those data concerning the effect of sham procedure on ambulatory and office blood pressure levels (ABP and OBP, respectively) Results: Six randomized, sham-controlled trials were identi fied and included in the meta-analysis. In total, 981 patients with hypertension were randomized in all 6 trials to undergo either RDN (n=585) or sham-procedure (n=396). It was documented that the sham procedure did not affect signi ficantly 24-h systolic ABP levels (MD:-1.15, 95% CI:-2.67 to 0.36, I^2=0%); however, it induced a signi ficant decrease in 24-h diastolic ABP levels by 1.52 mm Hg (95% CI:-2.53 to-0.51, I^2=0%). In addition, it was demonstrated that the sham procedure resulted in a signi ficant decrease in systolic OBP by 3.05 mm Hg (95% CI:-5.30 to-0.81 I^2=0%) and a non-signi ficant decrease in diastolic OBP by 0.65 mm Hg (95% CI:-2.03 to 0.73, I^2=0%). No major safety issues arose Conclusions: Sham procedure is a safe procedure, providing signi ficant or marginally non-signi ficant decrease in both ABP and OBP levels.