Renal Sympathetic Denervation: From acute renal nerve stimulation induced hemodynamic changes to long-term clinical perspectives

Worldwide there are many people with hypertension. However, the treatment of high blood pressure is not optimal and in many patients the blood pressure remains too high despite drug therapy. A potential new treatment for hypertension is renal sympathetic denervation (RDN); hereby the sympathetic nerves surrounding the renal arteries are denervated. The first results were promising regarding blood pressure reduction, but the first randomized sham-controlled studies showed disappointing results. Currently, the RDN procedure is under investigation to improve the procedure and select the appropriate hypertension patient category. In this thesis renal nerve stimulation (RNS) before and after renal denervation has been applied to improve the procedure. RNS was used both before and after RDN. Before RDN, RNS causes a rise in blood pressure, this effect is no longer present after RDN. This thesis describes the acute RNS-induced hemodynamic effects and changes in heart rate variability before and after RDN. In addition, we showed that patients who had no RNS-induced blood pressure increase after RDN had much better blood pressure lowering at follow-up compared to the patients who still had RNS-induced blood pressure rise. RNS may thus potentially be used to determine whether the denervation is complete. In addition, we describe in the thesis the possible future applications of RDN in other cardiovascular diseases characterized by sympathetic overdrive. Further research into the exact role of renal nerve stimulation during RDN is necessary, but this thesis has provided insight into the possible underlying mechanism of both RDN and RNS.