MO058DELAYED BUT SUSTAINED BLOOD PRESSURE AND SYMPATHETIC REDUCTION ONE YEAR AFTER RENAL DENERVATION IN DIALYSIS PATIENTS

Abstract

Introduction and Aims: Endovascular renal denervation is a catheter-based treatment for resistant hypertension that reduces afferent and efferent renal sympathetic nerve activity. In chronic kidney disease (CKD), elevated sympathetic activity has been causally linked to disease progression and cardiovascular sequelae. Although a persistent blood pressure-lowering effect post denervation has been demonstrated in a small number of trials in this population, the long-term effect on sympathetic activity remains elusive. We hypothesized that renal denervation in dialysis patients would reduce muscle sympathetic nerve activity (MSNA) resulting in reduced blood pressure (BP) and cardiovascular risk. Methods: One hundred and three dialysis patients were screened for uncontrolled BP (office BP > 140/90 mmHg despite clinical euvolaemia, whilst taking two or more anti-hypertensives at maximal tolerated doses). Nine patients were recruited into this proof-of-principle trial. Office and ambulatory blood pressure monitoring (ABPM) were performed at baseline, one, three and twelve months post denervation, along with recordings of supine MSNA. Bioimpedance spectroscopy was also recorded at similar time points to formalise patients' volume status. To assess the mechanistic impact of renal denervation, serum catecholamines, natriuretic peptides, adrenomedullin, renin and aldosterone were recorded. Heart rate variability analysis of 24h ambulatory ECG recordings was also undertaken, as was transthoracic echocardiography. Bilateral endovascular renal denervation with the multi-electrode EnligHTNTM catheter was then performed as described previously. Results: Office BP reduced from 179±28/90±17mmHg at baseline to 156±24/76 ±13mmHg at one month, 152±25/82±12mmHg at three months and 154±37/81 ±19mmHg by twelve months. The effect on ABPM was attenuated although did improve substantially with time, with a reduction from 173±19/92±11mmHg at baseline to 173 ±23/89±13 mmHg at one month, 165±24/88±11 at three months and 152±31/83±18 by twelve months. The systolic BP change was statistically significant by both measures of assessment (p<0.05). Alongside the observed BP change, there was an associated delayed reduction in MSNA (58.8±12.4 bursts/min at baseline, 58.8±14.9 bursts/min at one month, 58.9±13.2 bursts/min at three months but 53.7±13.0 bursts/min by twelve months), with regression of left ventricular hypertrophy and improvement of diastolic dysfunction and heart rate variability (p<0.05). One patient did however develop a pseudoaneurysm at the site of femoral artery puncture that needed surgical repair; another suffered a myocardial infarction four days post procedure. Conclusions: Renal denervation may offer an as yet unproven benefit to the CKD population, particularly for those on dialysis. Alongside a blood pressure lowering effect, pluripotent cardiovascular benefits seem to ensue, which could well be as a result of reduced afferent sympathetic nerve signalling. These are potentially of prognostic significance. Further larger, sham-controlled studies of this technique are warranted in the CKD population with follow-up continuing to at least 12 months.