Safety and efficacy of renal sympathetic denervation: a 9-year long-term follow-up of 24-hour ambulatory blood pressure measurements

BACKGROUND: Renal sympathetic denervation (RDN) has been shown to lower arterial blood pressure both in the presence and in the absence of antihypertensive medication in an observation period of up to 3 years. However, long-term results beyond 3 years are scarcely reported. METHODS: We performed a long-term follow-up on patients who were previously enrolled in a local renal denervation registry and who underwent radiofrequency RDN with the Symplicity Flex® renal denervation system between 2011 and 2014. The patients were assessed to evaluate their renal function by performing 24-hour ambulatory blood pressure measurement (ABPM), recording their medical history, and conducting laboratory tests. RESULTS: Ambulatory blood pressure readings for 24 h were available for 72 patients at long-term follow-up (FU) [9.3 years (IQR: 8.5–10.1)]. We found a significant reduction of ABP from 150.1/86.1 ± 16.9/12.0 mmHg at baseline to 138.3/77.1 ± 16.5/11.1 mmHg at long-term FU (P < 0.001 for both systolic and diastolic ABP). The number of antihypertensive medications used by the patients significantly decreased from 5.4 ± 1.5 at baseline to 4.8 ± 1.6 at long-term FU (P < 0.01). Renal function showed a significant but expected age-associated decrease in the eGFR from 87.8 (IQR: 81.0–100.0) to 72.5 (IQR: 55.8–86.8) ml/min/1.73 m(2) (P < 0.01) in patients with an initial eGFR > 60 ml/min/1.73 m(2), while a non-significant decrease was observed in patients with an initial eGFR < 60 ml/min/1.73 m(2) at long-term FU [56.0 (IQR: 40.9–58.4) vs. 39.0 (IQR: 13.5–56.3) ml/min/1.73 m(2)]. CONCLUSIONS: RDN was accompanied by a long-lasting reduction in blood pressure with a concomitant reduction in antihypertensive medication. No negative effects could be detected, especially with regard to renal function.