Early morphologic alterations in renal artery wall and renal nerves in response to catheter-based renal denervation procedure in sheep: difference between single-point and multiple-point ablation catheters.

摘要

Renal sympathetic hyperactivity is critically involved inhypertension pathophysiology; renal denervation (RDN) presentsa novel strategy for treatment of resistant hypertension cases.This study assessed effects of two RDN systems to detect acuteintravascular, vascular and peri-vascular changes in the renalartery, and renal nerve alterations, in the sheep. The proceduresusing a single-point or multi-point ablation catheters, SymplicityFlexTM, Medtronic versus EnligHTNTM, St. Jude Medical werecompared; the intact contralateral kidneys served as controls.Histopathological and immunohistochemical assessments wereperformed 48 h after RDN procedures; the kidney and suprarenalgland morphology was also evaluated. Special staining methodswere applied for histologic analysis, to adequately score theinjury of renal artery and adjacent renal nerves. These weremore pronounced in the animals treated with the multi-pointcompared with the single-point catheter. However, neither RDNprocedure led to complete renal nerve ablation. Forty-eight hoursafter the procedure no significant changes in plasma and renaltissue catecholamines were detected. The morphologic changeselicited by application of both RDN systems appeared to bedependent on individual anatomical variability of renal nerves inthe sheep. Similar variability in humans may limit the therapeuticeffectiveness of RDN procedures used in patients with resistanthypertension.