BACKGROUND/INTRODUCTION: The efficacy of catheter-based renal sympathetic denervation (RDN) in terms of blood pressure (BP) reduction has been questioned, while "real-world" data from registries are needed. In this study, we report the complete set of 12-month data on office and ambulatory BP changes as well as the predictors for BP response to RDN from a national registry.METHODS: In 4 Greek hospital centers, 79 patients with severe drug-resistant hypertension (age 59 ± 10 years, 53 males, body mass index 33 ± 5 kg/m; office BP and 24-h ambulatory BP were 176 ± 15/95 ± 13 and 155 ± 14/90 ± 12 mmHg, respectively, 4.4 ± 0.9 antihypertensive drugs) underwent RDN and were followed-up for 12 months in the Greek Renal Denervation Registry. Bilateral RDN was performed using percutaneous femoral approach and standardized techniques.RESULTS: Reduction in office systolic/diastolic BP at 6 and 12 months from baseline was -30/-12 and -29/-12 mmHg, while the reduction in 24-h ambulatory BP was -16/-9 and -15/-9 mmHg, respectively (p < 0.05 for all). Patients that were RDN responders (85%, n = 58), defined as an at least 10-mmHg decrease in office systolic BP at 12 months, compared to non-responders were younger (57 ± 9 vs 65 ± 8 years, p < 0.05), had higher baseline office systolic BP (176 ± 17 vs 160 ± 11 mmHg, p < 0.05) and 24-h systolic BP (159 ± 13 vs 149 ± 11 mmHg, p < 0.05). Stepwise logistic regression analysis revealed that age, obesity parameters, and baseline office BP were independent predictors of RDN response (p < 0.05 for both), but not the type of RDN catheter or the use of aldosterone antagonists. At 12 months, there were no significant changes in renal function and any new serious device or procedure-related adverse events.CONCLUSIONS: In our "real-world" multicenter national registry, the efficacy of renal denervation in reducing BP as well as safety is confirmed during a 12-month follow-up. Moreover, younger age, obesity, and higher levels of baseline systolic BP are independently related to better BP response to RDN.