Comparison of new-generation renal artery denervation systems: assessing lesion size and thermodynamics using a thermochromic liquid crystal phantom model

Raisi, Sara I. Al; Barry, Michael; Qian, Pierre; Bhaskaran, Abhishek; Pouliopoulos, Jim; Kovoor, Pramesh

doi:10.4244/eij-d-17-00278

Cited by 8 publications

(6 citation statements)

References 25 publications

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“…The newer multi‐electrode Symplicity Spyral is likely to offer a greater ablation consistency. However, it was found to have less heating depth than Symplicity Flex . Therefore, injury to 50% of nerve fibers may not be achievable when ablation is performed in the main vessel using Symplicity Spyral.…”

Section: Discussionmentioning

confidence: 99%

“…However, it was found to have less heating depth than Symplicity Flex. 15,16 Therefore, injury to 50% of nerve fibers may not be achievable when ablation is performed in the main vessel using Symplicity Spyral. Hence, RF ablation distal to the bifurcation in addition to the main vessel is now recommended when utilizing Symplicity Spyral, as nerve fibers are located closer to the intima in the branches compared to the main vessel.…”

Section: Discussionmentioning

confidence: 99%

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Comparison of two different radiofrequency ablation systems for renal artery denervation: Evaluation of short‐term and long‐term follow up

Raisi

Pouliopoulos

Qian

et al. 2018

Cathet Cardio Intervent

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Objectives To assess the clinical efficacy of renal artery denervation (RAD) in our center and to compare the efficacy of two different radiofrequency (RF) systems. Background Several systems are available for RF renal denervation. Whether there is a difference in clinical efficacy among various systems remains unknown. Methods Renal artery denervation was performed on 43 patients with resistant hypertension using either the single electrode Symplicity Flex (n = 20) or the multi‐electrode EnligHTN system (n = 23). Median post‐procedural follow‐up was 32.93 months. The primary outcome was post‐procedural change in office blood pressure (BP) within 1 year (short‐term follow‐up). Secondary outcomes were change in office BP between 1 and 4 years (long‐term follow‐up) and the difference in office BP reduction between the two systems at each follow‐up period. Results For the total cohort, mean baseline office BP (systolic/diastolic) was 174/94 mmHg. At follow‐up, mean changes in office BP from baseline were −19.70/−11.86 mmHg ( P < 0.001) and −21.90/−13.94 mmHg ( P < 0.001) for short‐term and long‐term follow‐up, respectively. The differences in office BP reduction between Symplicity and EnligHTN groups were 8.96/1.23 mmHg ( P = 0.42 for systolic BP, P = 0.83 for diastolic BP) and 9.56/7.68 mmHg ( P = 0.14 for systolic BP, P = 0.07 for diastolic BP) for short‐term and long‐term follow‐up, respectively. Conclusions In our cohort, there was a clinically significant office BP reduction after RAD, which persisted up to 4 years. No significant difference in office BP reduction between the two systems was found.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Comparison of two different radiofrequency ablation systems for renal artery denervation: Evaluation of short‐term and long‐term follow up

Raisi

Pouliopoulos

Qian

et al. 2018

Cathet Cardio Intervent

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“…In the entire model, all the outer surfaces of the tissue were grounded with zero current density. The initial potential was set to 0 V, and constant powers [12,15] of 4, 6, and 8 W were applied to the monopolar [24], spiral-based [32], and balloon-based applicators, respectively, for 60 s. Figure 3 shows the thermal and blood flow boundary conditions. Blood flow in the renal artery was considered an incompressible Newtonian fluid.…”

Section: Boundary and Initial Conditionsmentioning

confidence: 99%

“…The results indicated no change in serum creatinine after RF-RDN, no augmentation of medial damage or neointimal formation in the renal artery, and no or minimal damage to surrounding tissue. AI Raisi et al [12][13][14][15] conducted a series of experimental evaluations to investigate the efficacy of different RDN, including the Symplicity Flex system, EnligHTN system, and Symplicity Spyral system, and compared their lesion sizes to illustrate the ablation effect of different systems.…”

Section: Introductionmentioning

confidence: 99%

Comparison of ablation characteristics of three different radiofrequency applicators in renal sympathetic denervation

Cheng

Liu

Tian

et al. 2021

International Journal of Hyperthermia

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Objective: Renal sympathetic denervation (RDN) is an alternative treatment for resistant hypertension (RH). This study aims to compare ablation effects using three radiofrequency applicators (i.e., balloonbased four electrodes, spiral and monopolar devices). Methods: An idealized three-dimensional model of the renal artery was established using COMSOL Multiphysics to mimic radiofrequency ablation (RFA). Radiofrequency (RF) energy was delivered to the tissue at the same simulation settings, i.e., 4, 6, and 8 W for 60 s, using the three abovementioned RF applicators. The temperature distribution in the tissue was calculated using the coupled electrical-thermal-fluid finite element method. Lesion borders were defined using 50 C isotherms. The maximum lesion depth, width, area, and circumferential coverage rate were compared among the three applicators at a blood flow of 0.4 m/s. Monopolar RF ablations in a renal artery phantom model were performed to validate the reliability of the simulation method. Results: The balloon-based system yields greater lesion depths and widths compared with spiral and monopolar denervation under the same power. The range of maximum lesion depth is 1.58-3.11 mm for balloon-based RDN, 0.90-1.81 mm for spiral RDN and 1.12-2.38 mm for monopolar RDN, at a power of 4-8 W. The corresponding ranges of maximum lesion width are 2.22-5.73, 1.48-3.54, and 1.93-5.31 mm, respectively, and the circumferential coverage rates of the renal artery are 41.43%-91.99%, 31.71%-66.23%, and 9.55%-23.06%, respectively. The average velocity after balloonbased, spiral, and monopolar RDN increases by 3, 5, and 1 cm/s, respectively. The validation of the computer model offered prediction errors are <5% in terms of temperature at different locations (i.e., 2, 4, and 8 mm). Conclusions: In terms of lesion size, balloon-based RDN appears to be the best option for the treatment of RH. However, the change in flow velocity in the arterial flow field suggests that its hemodynamic changes must be prioritized for investigating its safety. Although spiral catheter ablation yields the smallest lesion size and a significant change in flow velocity in the flow field, its coverage rate is larger than that of monopolar RDN; compared with balloon-based RDN, it did not obstruct most of the blood flow.

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“…Radiofrequency lesion size is an important determinant for successful denervation that could be affected by several factors including ablation power, electrode surface area, ablation duration and catheter contact force [37]. Differences in lesion size between various RF systems was demonstrated using a RA phantom model [41,42]. Therefore, evaluation of individual systems is important in order to inform clinicians regarding those devices.…”

Section: Ablation Modalities Used In Renal Artery Denervation Radiofrmentioning

confidence: 99%

Renal Artery Denervation in Resistant Hypertension: The Good, The Bad and The Future

Raisi

Pouliopoulos

Swinnen

et al. 2020

Heart, Lung and Circulation

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Comparison of new-generation renal artery denervation systems: assessing lesion size and thermodynamics using a thermochromic liquid crystal phantom model

Cited by 8 publications

References 25 publications

Comparison of two different radiofrequency ablation systems for renal artery denervation: Evaluation of short‐term and long‐term follow up

Comparison of two different radiofrequency ablation systems for renal artery denervation: Evaluation of short‐term and long‐term follow up

Comparison of ablation characteristics of three different radiofrequency applicators in renal sympathetic denervation

Renal Artery Denervation in Resistant Hypertension: The Good, The Bad and The Future

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