Non-invasive quantification of anatomical and functional renal artery vessel wall changes in patients with resistant hypertension undergoing renal denervation using MRI

Abstract

Background Renal Denervation (RDN) is a novel therapy for patients with resistant hypertension. Its direct effects on the renal arteries in humans are poorly examined. We sought to assess renal artery distensibility noninvasively using magnetic resonance imaging (MRI) and to study the effects of RDN on anatomical and functional changes of the renal artery vessel wall. Methods 19 patients with resistant hypertension undergoing RDN were prospectively included. A 3.0T MRI including contrast-enhanced renal artery angiography was performed before the RDN procedure and at 6-month follow-up. In each patient the proximal part of both renal arteries was imaged for the cross-sectional area measurements using cine spiral MRI. Renal artery sharpness was evaluated with a quantitative analysis tool (Soap-Bubble Tool). In a subgroup of 11 patients, the distensibility (mm Hg(-1) × 10(3)) was determined as (maximum lumen area minimal lumen area)/(pulse pressure × minimal lumen area). The pulse pressure was calculated as the difference between the systolic and diastolic brachial blood pressure. Results Renal artery sharpness values before and 6 months after RDN did not differ significantly (49.15 ± 7.11 vs 47.43 ± 8.5, respectively, p = 0.255). Similarly, renal artery distensibility was not significantly different before RDN