Catheter-Based Renal Denervation Exacerbates Blood Pressure Fall During Hemorrhage.

BACKGROUND

Clinical trials applying catheter-based radiofrequency renal denervation (RDN) demonstrated a favorable safety profile with minimal acute or procedural adverse events. Whether ablation of renal nerves adversely affects compensatory responses to hemodynamic challenge has not been extensively investigated.

OBJECTIVES

The aim of this study was to examine the effect of RDN on mean arterial pressure, renal function, and the reflex response to hemorrhage in sheep with normotension (control) or with hypertensive chronic kidney disease (CKD).

METHODS

Sheep underwent RDN (control-RDN, n = 8; CKD-RDN, n = 7) or sham procedures (control-intact, n = 6; CKD-intact, n = 7). Response to hemorrhage (20% loss of blood volume), including plasma renin activity, was assessed at 2 and 5 months post-procedure.

RESULTS

RDN caused a complete reversal of hypertension and improved renal function in CKD-RDN sheep (p < 0.0001 for 2 and 5 months vs. pre-RDN). In response to hemorrhage, mean arterial pressure fell in all groups, with the fall being greater in the RDN than the intact group (2-month fall in mean arterial pressure: control-intact, -10 ± 1 mm Hg; control-RDN, -15 ± 1 mm Hg; p < 0.05; CKD-intact, -11 ± 3 mm Hg; CKD-RDN, -19 ± 9 mm Hg; p < 0.001). Hemorrhage increased heart rate and plasma renin activity in intact sheep, but these responses were significantly attenuated in control-RDN and CKD-RDN animals. Responses to hemorrhage were remarkably similar at 2 and 5 months post-RDN, which suggests that nerve function had not returned within this time frame.

CONCLUSIONS

In hypertensive CKD sheep, RDN reduced blood pressure and improved basal renal function but markedly compromised compensatory hemodynamic responses to hemorrhage. Therefore, the capacity to respond to a physiological challenge to body fluid homeostasis may be compromised following RDN.