Abstract 109: Changes in Plasma Renin Activity After Renal Denervation in the Spyral Htn-Off Med Trial

Abstract

Results from recent sham-controlled clinical trials demonstrate the efficacy of renal denervation (RDN) in blood pressure reduction, however the effects of RDN on the renin-angiotensin system are not clear. We sought to evaluate changes in plasma renin activity (PRA) and serum sodium levels after RDN in the absence of anti-hypertensive medications in the SPYRAL HTN-OFF MED trial. SPYRAL HTN-OFF MED is a randomized, sham-controlled trial to evaluate the impact of RDN in the absence of anti-hypertensive medications. Patients were enrolled with an office systolic BP (SBP) ≥150 and <180 mmHg, office diastolic BP ≥90 mmHg, and a mean 24-hour SBP ≥140 and <170 mmHg. Patients were randomized 1:1 to RDN with the SYMPLICITY Spyral™ catheter (N=38) or sham procedure (N=42). PRA and serum sodium levels were measured at baseline and 3 months post-procedure. Changes were expressed using medians and interquartile ranges and compared between groups using the Mann-Whitney U-test. Change in PRA from baseline to 3 months was significantly greater for the RDN group (n=23) -0.15 ng/mL/h [-0.76, -0.02] compared to the sham control group (n=33) 0.02 ng/mL/h [-0.16, 0.16]; p=0.018 ( Figure ). Comparison of 3-month changes in PRA using a Wilcoxon test stratified by 3 equal groups of baseline PRA also found a significant difference between groups (p=0.033). Changes in sodium levels were similar between groups: 0 mmol/L [-2, 2] (RDN, N=37) vs. 0 mmol/L [-1, 1] (control, N=41), p=0.920). In this sham-controlled feasibility trial, renal denervation was associated with a reduction in PRA but no difference in serum sodium levels was observed. The impact on sodium excretion will need to be assessed in future studies.