Effect of renal ablation on blood pressure and muscle sympathetic nerve activity in chronic kidney disease patients (LB722)

Abstract

Chronic kidney disease (CKD) is associated with renal sympathetic hyperactivity and uncontrolled hypertension. Catheter‐based renal ablation may reduce arterial blood pressure and muscle sympathetic nerve activity (MSNA) in patients with drug resistant hypertension. A cohort of 4 dialysis patients are reported who had uncontrolled hypertension despite two agents and clinical normovolemia, and in whom successful MSNA and BP recordings were obtained in both pre and post ablation tests. These patients were tested to determine whether renal ablation would reduce blood pressure and whether changes in blood pressure would be associated with changes in MSNA. This was achieved by comparing burst activity (incidence and frequency) and action potential (AP) composition (APs/burst, APs/min and APs/100 heart beats) pre‐ and one month post‐ablation. Analyses were conducted using software that detected AP content of the multi‐unit recording in human neural signals. Compared to the pre session, these patients had reductions in average ambulatory blood pressure (Systolic 178 ± 18 to 158 ± 25 mmHg p=0.04 and diastolic 95 ± 13 to 82 ± 7 mmHg p=0.046) post‐ablation. Average burst frequency (64 ± 15 to 61 ± 18 p=0.58) and burst incidence (84 ± 12 to 82 ±19 p=0.6) were unaffected by ablation. However, ablation increased average APs/burst (4.5 ± 1.3 to 7 ± 2.3 p= 0.03), APs/min (223 ± 103 to 423 ± 202 p=0.039) and APs/100 heart beats (297 ± 117 to 582 ± 280 p=0.04). These data suggest that the observed decrease in blood pressure was not associated with changes in burst activity (frequency and incidence): However, the observed increases in sympathetic AP content/burst and per minute suggest an affect of ablation on AP recruitment and synchronization.Grant Funding Source: Supported by The Kidney and Health and Disease reserach theme Univeristy of Otago