DIFFERING EFFECTS OF RENAL DENERVATION ON BLOOD PRESSURE AND SYMPATHETIC NERVE TRAFFIC: A SYSTEMATIC REVIEW AND META-ANALYSIS

Objective: Whether and to what extent the reported BP lowering effects of renal denervation (RD) are mediated by a sympathetic deactivation induced by the procedure is still largely undefined. We examined this issue by performing a meta-analysis of the microneurographic studies published so far based on the evaluation of the blood pressure (BP) and muscle sympathetic nerve traffic (MSNA) responses to RD. Design and method: The meta-analysis was based on 12 studies including a total of 394 patients with resistant hypertension underwent RD and followed up to 12 months. Evaluation was extended to the relationships of MSNA with heart rate (HR) and clinic or ambulatory blood pressure (BP) values (expressed such as mean and 95% confidence interval). Results: Baseline MSNA values amounted to 48.25 (43.86-52.64) bursts/minute, clinic HR to 66.35 (65.02-67.67) beats/minute and systo/diastolic clinic BP to 167.3 (157.6-177.01) and 90.54 (84.81-96.27) mmHg. RD caused a significant BP reduction at 3/6/12 months following the procedure amounting to 12.6 mmHg for systolic (range 20.9 to 4.39 mmhg, p = 0.003) and to 6.4 mmHg for diastolic BP (range -11.9 t0 0.9 mmHg, p = 0.02) respectively. No significant change in MSNA (-2.65, range -6.7 to 1.4 bursts/minute, P = NS) and HR (-0.58, range -3.98 to 2.81 b/min, P = NS) were concomitantly observed. No relationship was found between the number of renal ablations and the magnitude of the blood pressure or MSNA changes, this being the case also for HR. Conclusions: This meta-analysis, the first ever done on the MSNA responses to RD, shows that in a consistent number of patients underwent RD, the BP lowering effects of the procedure are not accompanied by any significant change in 2 adrenergic markers, i.e. MSNA and HR, and thus appear not to be mediated by any sympathetic deactivation.