HIGH RENAL RESISTANCE INDICES AND HIGH PULSE PRESSURE MAY LIMIT NEPHROPROTECTIVE EFFICACY OF RENAL DENERVATION IN PATIENTS WITH RESISTANT HYPERTENSION AND TYPE 2 DIABETES MELLITUS

Abstract

Objective: The combination of diabetes mellitus (DM) and resistant hypertension (RHTN) is associated with an increased risk of development and progression of chronic kidney disease (CKD). It has been shown that renal denervation have nephroprotective efficacy by slowing the decline in renal function in some patients. The aim of the study was to identify factors limiting the nephroprotective effect of renal denervation in patients with RHTN and DM. Design and method: Twenty seven patients with RHTN and type 2 DM were included in single-arm prospective interventional study (protocol number NCT01499810 on ClinicalTrial.gov) (mean age 61.6 ± 7.3 years, mean office (systolic/diastolic) blood pressure (BP) 171.8 ± 21.9/87.7 ± 17.7mmHg, mean eGFR 72.1 ± 19.9 ml/min/1.73 m2, HbA1c 6.3 ± 1.1%, 7 patients (26%) with stage 3 CKD, 8 men). All patients were underwent to ambulatory 24-hour BP, renal Doppler ultrasound and assessment of eGFR (CKD-EPI formula) at baseline and 3 years follow-up. The patients were advised not to change their medication regimen during the study. Nineteen patients completed 3 years of follow-up. The renal outcomes were 1) a decrease in eGFR = > 30% from baseline; 2) decrease in eGFR > 5 ml/min/1.73 m2/year; 3) their combination. Results: There was a significant decrease in mean 24-hour BP (SBP/DBP) (-14.3 ± 20.6 / -7.7 ± 10.6 mmHg, P = 0.02 /0.04). Six patients (32%) had renal outcomes at 3 years follow-up (5 pts (26%) with both outcomes, 5 patients (26%) had a decrease in eGFR = > 30% from baseline and 5 patients had a decrease in eGFR > 5 mL/min/1.73 m2/year). At baseline, patients with renal outcomes compared with patients without them had higher values of both 24-hour pulse BP (90.3 ± 7.1 vs 73.1 ± 12.5 mmHg, p = 0.007) and its variability (15.6 ± 2.6 versus 11.7 ± 3.0 mmHg, p = 0.01), as well as a higher mean value of renal resistive indices (RI) (RI in the trunk 0.79 ± 0.04 vs0.71 ± 0.06, p = 0.007; RI in segmental arteries 0.75 ± 0.08 vs 0.66 ± 0.08, p = 0.04). Conclusions: Our data indicate that a high value of pulse blood pressure and its variability, as well as high indices of renal resistance, can limit the nephroprotective efficacy of renal denervation, possibly due to chronic intrarenal barotrauma and irreversible changes in the kidneys.