Renal sympathetic denervation increases renal blood volume per cardiac cycle: a serial magnetic resonance imaging study in resistant hypertension

Abstract

Aim: Preclinical studies have demonstrated improvements in renal blood flow after renal sympathetic denervation (RSDN); however, such effects are yet to be confirmed in patients with resistant hypertension. Herein, we assessed the effects of RSDN on renal artery blood flow and diameter at multiple time points post-RSDN. Methods and results: Patients (n=11) with systolic blood pressures ≥160 mmHg despite taking three or more antihypertensive medications at maximum tolerated dose were recruited into this single-center, prospective, non-blinded study. Magnetic resonance imaging indices included renal blood flow and renal artery diameters at baseline, 1 month and 6 months. In addition to significant decreases in blood pressures (p<0.0001), total volume of blood flow per cardiac cycle increased by 20% from 6.9±2 mL at baseline to 8.4±2 mL (p=0.003) at 1 month and to 8.0±2 mL (p=0.04) 6 months post-procedure, with no changes in the renal blood flow. There was a significant decrease in renal artery diameters from 7±2 mm at baseline to 6±1 mm (p=0.03) at 1 month post-procedure. This decrease was associated with increases in maximum velocity of blood flow from 73±20 cm/s at baseline to 78±19 cm/s at 1 month post-procedure. Notably, both parameters reverted to 7±2 mm and 72±18 cm/s, respectively, 6 months after procedure. Conclusion: RSDN improves renal physiology as evidenced by significant improvements in total volume of blood flow per cardiac cycle. Additionally, for the first time, we identified a transient decrease in renal artery diameters immediately after procedure potentially caused by edema and inflammation that reverted to baseline values 6 months post-procedure.

Long‐Term Effects of Renal Sympathetic Denervation on Hypertensive Patients With Mild to Moderate Chronic Kidney Disease

“…Recently, Ott and colleagues conducted an observational pilot study of 27 patients with CKD stages 3 and 4 and reported that the RSD treatment of hypertension decreased BP and augmented eGFR by +1.5±10 mL/min/1.73 m 2 , halting the decline in renal function. Consistent with our findings, unpublished data from the Adelaide and Renal EnligHTN Blood Flow study, which was presented at the American Heart Association Scientific Sessions 2014, showed increased eGFR and a reduction in the levels of urinary protein excretion and plasma aldosterone in refractory hypertension patients with eGFR ≥45 mL/min/1.73 m 2 6 months after renal denervation …”

“…Consistent with our findings, unpublished data from the Adelaide and Renal EnligHTN Blood Flow study, which was presented at the American Heart Association Scientific Sessions 2014, showed increased eGFR and a reduction in the levels of urinary protein excretion and plasma aldosterone in refractory hypertension patients with eGFR ≥45 mL/min/1.73 m 2 6 months after renal denervation. 16 Increased sympathetic tone, a well-known risk factor for CVD, is also frequently present in patients with essential hypertension and in those with CKD. [37][38][39] In both hypertension and renal failure, the mechanisms of the hyperadrenergic state are manifold and include reflex and neurohumoral pathways.…”

“…[10][11][12][13] This finding suggests a promising benefit to patients with CKD and refractory hypertension. In addition, in two studies with a short follow-up period, RSD was associated with a postprocedure increase in glomerular filtration [14][15][16] and a reduction in albuminuria. 14,15,17 This study is the first to perform a long-term analysis of the effects of percutaneous RSD on estimated glomerular filtration rate (eGFR) and albumin excretion in patients with CKD and refractory hypertension.…”

“…This finding suggests a promising benefit to patients with CKD and refractory hypertension. In addition, in two studies with a short follow‐up period, RSD was associated with a postprocedure increase in glomerular filtration and a reduction in albuminuria …”

Sympathetic Activation in Hypertensive Chronic Kidney Disease – A Stimulus for Cardiac Arrhythmias and Sudden Cardiac Death?

“…While RDN has been used predominantly to treat resistant hypertensive patients ( Figure 5; Symplicity et al, 2010;Krum et al, 2014), it is likely of beneficial value in CKD. Indeed, RDN has demonstrated GFR improvement (Kiuchi et al, 2013(Kiuchi et al, , 2014Delacroix et al, 2014) and reduction of albuminuria (Kiuchi et al, 2013(Kiuchi et al, , 2014Ott et al, 2014;Schmieder et al, 2014), although these studies are limited by a short follow up period. Kiuchi et al (2016a) reported cardiac structural and functional enhancement, which were associated with eGFR improvement in a resistant hypertensive cohort with CKD at follow-up 6 month FIGURE 6 | Sympathetic and parasympathetic nervous system cardiac arrhythmogenic effects.…”