The biophysics of renal sympathetic denervation using radiofrequency energy

Abstract

Renal sympathetic denervation is currently performed in the treatment of resistant hypertension by interventionists who otherwise do not typically use radiofrequency (RF) energy ablation in their clinical practice. Adequate RF lesion formation is dependent upon good electrode-tissue contact, power delivery, electrode-tissue interface temperature, target-tissue impedance and the size of the catheter's active electrode. There is significant interplay between these variables and hence an appreciation of the biophysical determinants of RF lesion formation is required to provide effective and safe clinical care to our patients. In this review article, we summarize the biophysics of RF ablation and explain why and how complications of renal sympathetic denervation may occur and discuss methods to minimise them.

Neuropeptide Y as an indicator of successful alterations in sympathetic nervous activity after renal sympathetic denervation

“…RSD is an interventional treatment option in resistant HT when optimal medical treatment fails [7][8][9][10][11][12][13][14][15][16][17]. However, data from the randomized, blinded HTN-3 trial did not show a significant reduction of SBP in patients with resistant HT compared with sham controls 6 months after RSD [18].…”

“…The RSD systems currently in use, with single or multiple electrodes, do not provide intra-procedural feedback on successful denervation of the sympathetic nerve fibers that are the target of this specific interventional therapy. Up until now, there is limited clinical evidence confirming a successful reduction of the sympathetic activity after RSD [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23].…”

“…The persistence of high blood pressure (BP) in patients with resistant HT is partially regulated by the renal sympathetic nervous system (SNS) [2][3][4][5][6]. Therefore, renal sympathetic denervation (RSD) has been developed as an interventional treatment option for patients with uncontrolled HT when optimal medical treatment fails [7][8][9][10][11][12][13][14][15][16][17]. The randomized, blinded HTN-3 trial failed to meet its primary efficacy endpoint as the study did not show a significant reduction of systolic blood pressure (SBP) in patients with resistant hypertension 6 months after RSD compared with sham controls [18].…”

Renal Denervation for the Treatment of Cardiovascular High Risk-Hypertension or Beyond?

“…27,28 The effectiveness of the radiofrequency procedure with adequate lesion formation is dependent on electrode-tissue contact, power delivery, electrode-tissue interface, temperature, and target tissue impedance, which all affect the depths of the lesions. 27 For effective renal denervation, it is important to provide a circumferential application of energy deployment. The first device was a single electrode, nonsteerable and later steerable, catheter (Symplicity/ARDIAN-Medtronic) receiving Communaute Europeenne-approval.…”

Retinal microperfusion after renal denervation in treatment-resistant hypertensive patients

“…In the last years, catheter-based renal denervation (RDN) has emerged as an interventional approach for safe BP reduction in patients with TRH [9][10][11][12][13][14][15][16]. Moreover, it was shown that RDN impacts on renal microcirculation, namely a reduction of albuminuria [17].…”