Renal denervation therapy for resistant hypertension: a clinical update

Effects of Renal Denervation on Insulin Sensitivity and Inflammatory Markers in Nondiabetic Patients with Treatment-Resistant Hypertension

Increased sympathetic activity is important in the pathogenesis of hypertension and insulin resistance. Afferent signaling from the kidneys elevates the central sympathetic drive. We investigated the effect of catheter-based renal sympathetic denervation (RDN) on glucose metabolism, inflammatory markers, and blood pressure in nondiabetic patients with treatment-resistant hypertension. Eight subjects were included in an open-labelled study. Each patient was studied before and 6 months after RDN. Endogenous glucose production was assessed by a 3-³H glucose tracer, insulin sensitivity was examined by hyperinsulinemic euglycemic clamp, hormones and inflammatory markers were analyzed, and blood pressure was measured by office blood pressure readings and 24-hour ambulatory blood pressure monitoring. Insulin sensitivity (M-value) increased nonsignificantly from 2.68 ± 0.28 to 3.07 ± 0.41 (p = 0.12). A significant inverse correlation between the increase in M-value and BMI 6 months after RDN (p = 0.03) was found, suggesting beneficial effects on leaner subjects. Blood pressure decreased significantly, but there were no changes in hormones, inflammatory markers, or endogenous glucose production. Our results indicate that RDN may improve insulin sensitivity in some patients with treatment-resistant hypertension, albeit confirmation of these indications of beneficial effects on leaner subjects awaits the outcome of larger randomized controlled studies.

Effects of Renal Sympathetic Denervation on Arterial Stiffness and Blood Pressure Control in Resistant Hypertensive Patients: A Single Centre Prospective Study

Renal denervation (RD) is an intriguing treatment strategy for resistant hypertension. However, limited data are available about its long time efficacy as well as its effects on intermediate phenotypes like arterial stiffness and carotid IMT. 12 patients (9 males, mean 69 years) with resistant hypertension underwent bilateral RDN (Medtronic System) since April 2012 in Niguarda Ca' Granda Hospital (Milan). Patients were studied before intervention, and at 1, 3, 6 and 12 months after RD. Carotid intima media thickness (Esaote Mylab) and carotid-femoral pulse wave velocity (Complior, Alam medical) were assessed at each step. Compared to baseline, patients showed a marked reduction of office systolic blood pressure at each follow-up step (p < 0.05 versus baseline for all steps) as well as pulse wave velocity (p < 0.01 at 1 year versus baseline). Moreover, reduction in pulse wave velocity was higher than the expected value obtained only considering blood pressure drop. Conversely, no significant effect was observed on diastolic blood pressure as well as carotid intima-media thickness. In our study, renal denervation was a safe and effective procedure. The BP lowering effect was maintained during follow-up and a beneficial effect on arterial stiffness was observed, which implies that this effect can't passively originate from the BP fall but rather from an improvement of arterial mechanical properties, possibly related to a reduced sympathetic arterial drive.