Renal denervation may attenuate the severity of MRI-signs of vascular wall damage in diabetic patients with resistant hypertension due to the anti-inflammatory effect

Abstract

Objective . The aim of this study was to investigate the long-term effect of renal denervation (RDN) on MRIcharacteristics of renal artery (RA) wall in diabetic patients with resistant hypertension (RHTN). Design and methods . We included 19 diabetic patients with RHTN (mean age 61,9 ± 6,8 years; 6 men; HbA1c 6,6 ± 1,4 %; mean blood pressure (BP) 24h 159,5 ± 18,9 / 82,2 ± 13,7 mm Hg) who underwent MRI of the RA before and 12 months after RDN. The measurement of signal intensity (SI) of RA wall based on two-dimensional T1-weighted spin-echo images was done before and after the administration of a gadolinium-based contrast agent. The index of enhancement (IE) was calculated as ratio of SI post-to-precontrast enhancement. All patients underwent ambulatory 24-hour (24h) BP monitoring, lab tests (serum hsC-reactive protein (CRP), tumor necrosis factoralpha (TNF-α)) at baseline and 12-month follow-up. On average, patients were taking 4 (3–6) antihypertensive drugs. The mean number of ablations was 13 ± 1,8 (10–16). Patients were instructed not to change the treatment regimen throughout the study. At 12-month follow up MRI of RA was available for 16 patients. Results . After RDN there was a significant comparable decrease in IE of RA wall for both sides (IE mean values for right and left sides: from 1,7 ± 0,4 to 1,4 ± 0,3, p = 0,02 for the main RA; from 1,7 ± 0,5 to 1,4 ± 0,2, p = 0,04 for the middle parts of RA; from 1,9 ± 0,4 to 1,4 ± 0,3, p = 0,001 for distal branches of RA). In addition, RDN reduced the 24h BP (systolic / diastolic) by –15,1/–10,0 mm Hg, p < 0,001 as well as reduced the level of TNF-α (from 4,6 ± 3,8 to 3,4 ± 2,5 pg/ml, p = 0,03) and the level of hsCRP (from 6,5 ± 3,4 to 5,9 ± 3,2mg/L, p = 0,003). There was no direct relation between the IE and BP reduction. At the same time, the change in IE of middle part of RA after RD was directly related to decrease in both hsCRP level (R = 0,62, p = 0,03) and TNF-α level (R = 0,56, p = 0,04). Conclusions . The beneficial effect of RDN on the RA wall is associated with the attenuation of systemic subclinical inflammation.