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Does complete renal denervation translate into superior clinical outcomes? Lessons learned from denervation of accessory renal arteries.

Mendelsohn FO - Clin Res Cardiol (2014)

Bottom Line: The "completeness" of renal nerve injury following renal denervation correlates with treatment-based variables such as the depth of ablation, the number of ablations along the length of the artery, and the number of renal arteries successfully ablated.Renal denervation techniques targeting only main renal arteries may lead to suboptimal results in patients with accessory renal artery anatomy.Technological differences among the different systems may make some more suited for this common anatomical variant.

View Article: PubMed Central - PubMed

Affiliation: Interventional Hypertension Therapies Program, Cardiology PC, 801 Princeton Avenue, S.W., Suite 707, Birmingham, AL, 35211, USA, fmendelsohn@cardiologypc.com.

ABSTRACT
Pre-clinical studies of renal denervation would suggest that the extent of renal nerve injury correlates with outcomes. The "completeness" of renal nerve injury following renal denervation correlates with treatment-based variables such as the depth of ablation, the number of ablations along the length of the artery, and the number of renal arteries successfully ablated. Renal denervation techniques targeting only main renal arteries may lead to suboptimal results in patients with accessory renal artery anatomy. Technological differences among the different systems may make some more suited for this common anatomical variant. The early clinical experience with renal denervation of accessory renal arteries highlights the importance of complete renal denervation for clinical success.

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Reduction in office-based systolic BP 6 months following renal denervation treatment––Black bars represent patients without accessory renal arteries who had renal denervation treatment. Graybars represent patients with “complete” treatment of accessory renal arteries (as defined by Id et al. [8]). a Reductions following treatment with the Symplicity system [8]. b Reductions following treatment with the Vessix System (Sievert H. REDUCE-HTN Clinical Study Interim 6 and 12 months data. TCT 2013. San Francisco, October 28, 2013)
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Fig1: Reduction in office-based systolic BP 6 months following renal denervation treatment––Black bars represent patients without accessory renal arteries who had renal denervation treatment. Graybars represent patients with “complete” treatment of accessory renal arteries (as defined by Id et al. [8]). a Reductions following treatment with the Symplicity system [8]. b Reductions following treatment with the Vessix System (Sievert H. REDUCE-HTN Clinical Study Interim 6 and 12 months data. TCT 2013. San Francisco, October 28, 2013)

Mentions: Since the majority of renal nerves terminate at vascular structures within the kidney [9], nerve traffic to and from the kidney likely corresponds to the blood supply, traveling with both accessory and main renal arteries. So patients with accessory renal arteries may fail to respond if treated with a denervation technique targeting nerves only in the main renal artery—just as was observed by Id and colleagues [8]. Yet why, in their study, was the blood pressure-lowering response in the subgroup with “complete” denervation of accessory renal arteries less than that in the group with only main renal artery trunks (Fig. 1a)? This difference may in part be explained by limitations of the Symplicity renal denervation system for ablation of accessory renal arteries. The Symplicity system is composed of a single electrode monopolar radiofrequency ablation catheter connected to an automated generator. Energy passes from the generator through the catheter to an external grounding pad, which serves as a far field electrode. The generator delivers up to 8 W of power to the catheter tip causing heating of the adjacent tissue and consequent nerve injury. The system avoids overheating of the tissue by monitoring temperature from a thermistor near the electrode tip, shutting off power if the temperature exceeds a predetermined threshold. Cooling of the catheter tip from renal blood flow is critical to avoid overheating. In low-flow conditions with inadequate cooling, the generator will terminate energy delivery to prevent excessive tissue damage. Ablation will be interrupted, and denervation efficiency potentially compromised. Fig. 1


Does complete renal denervation translate into superior clinical outcomes? Lessons learned from denervation of accessory renal arteries.

Mendelsohn FO - Clin Res Cardiol (2014)

Reduction in office-based systolic BP 6 months following renal denervation treatment––Black bars represent patients without accessory renal arteries who had renal denervation treatment. Graybars represent patients with “complete” treatment of accessory renal arteries (as defined by Id et al. [8]). a Reductions following treatment with the Symplicity system [8]. b Reductions following treatment with the Vessix System (Sievert H. REDUCE-HTN Clinical Study Interim 6 and 12 months data. TCT 2013. San Francisco, October 28, 2013)
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4129223&req=5

Fig1: Reduction in office-based systolic BP 6 months following renal denervation treatment––Black bars represent patients without accessory renal arteries who had renal denervation treatment. Graybars represent patients with “complete” treatment of accessory renal arteries (as defined by Id et al. [8]). a Reductions following treatment with the Symplicity system [8]. b Reductions following treatment with the Vessix System (Sievert H. REDUCE-HTN Clinical Study Interim 6 and 12 months data. TCT 2013. San Francisco, October 28, 2013)
Mentions: Since the majority of renal nerves terminate at vascular structures within the kidney [9], nerve traffic to and from the kidney likely corresponds to the blood supply, traveling with both accessory and main renal arteries. So patients with accessory renal arteries may fail to respond if treated with a denervation technique targeting nerves only in the main renal artery—just as was observed by Id and colleagues [8]. Yet why, in their study, was the blood pressure-lowering response in the subgroup with “complete” denervation of accessory renal arteries less than that in the group with only main renal artery trunks (Fig. 1a)? This difference may in part be explained by limitations of the Symplicity renal denervation system for ablation of accessory renal arteries. The Symplicity system is composed of a single electrode monopolar radiofrequency ablation catheter connected to an automated generator. Energy passes from the generator through the catheter to an external grounding pad, which serves as a far field electrode. The generator delivers up to 8 W of power to the catheter tip causing heating of the adjacent tissue and consequent nerve injury. The system avoids overheating of the tissue by monitoring temperature from a thermistor near the electrode tip, shutting off power if the temperature exceeds a predetermined threshold. Cooling of the catheter tip from renal blood flow is critical to avoid overheating. In low-flow conditions with inadequate cooling, the generator will terminate energy delivery to prevent excessive tissue damage. Ablation will be interrupted, and denervation efficiency potentially compromised. Fig. 1

Bottom Line: The "completeness" of renal nerve injury following renal denervation correlates with treatment-based variables such as the depth of ablation, the number of ablations along the length of the artery, and the number of renal arteries successfully ablated.Renal denervation techniques targeting only main renal arteries may lead to suboptimal results in patients with accessory renal artery anatomy.Technological differences among the different systems may make some more suited for this common anatomical variant.

View Article: PubMed Central - PubMed

Affiliation: Interventional Hypertension Therapies Program, Cardiology PC, 801 Princeton Avenue, S.W., Suite 707, Birmingham, AL, 35211, USA, fmendelsohn@cardiologypc.com.

ABSTRACT
Pre-clinical studies of renal denervation would suggest that the extent of renal nerve injury correlates with outcomes. The "completeness" of renal nerve injury following renal denervation correlates with treatment-based variables such as the depth of ablation, the number of ablations along the length of the artery, and the number of renal arteries successfully ablated. Renal denervation techniques targeting only main renal arteries may lead to suboptimal results in patients with accessory renal artery anatomy. Technological differences among the different systems may make some more suited for this common anatomical variant. The early clinical experience with renal denervation of accessory renal arteries highlights the importance of complete renal denervation for clinical success.

Show MeSH
Related in: MedlinePlus