Author + information
- Received April 26, 2014
- Revision received July 1, 2014
- Accepted July 7, 2014
- Published online September 16, 2014.
- Abraham R. Tzafriri, PhD∗∗ (, )
- Felix Mahfoud, MD†,
- John H. Keating, DVM, DACVP∗,
- Peter M. Markham, MS∗,
- Anna Spognardi, BA∗,
- Gee Wong, BS, HT∗,
- Kristine Fuimaono, BS‡,
- Michael Böhm, MD† and
- Elazer R. Edelman, MD, PhD§,‖
- ∗CBSET Inc., Lexington, Massachusetts
- †Klinik für Innere Medizin III, Kardiologie, Angiologie, und Internistische Intensivmedizin, Universitätsklinikum des Saarlandes, Homburg/Saar, Germany
- ‡Biosense Webster, Irwindale, California
- §Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, Massachusetts
- ‖Cardiovascular Division, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
- ↵∗Reprint requests and correspondence:
Dr. Abraham R. Tzafriri, CBSET Inc., 500 Shire Way, Lexington, Massachusetts 02421.
Background Renal denervation is a new interventional approach to treat hypertension with variable results.
Objectives The purpose of this study was to correlate response to endovascular radiofrequency ablation of renal arteries with nerve and ganglia distributions. We examined how renal neural network anatomy affected treatment efficacy.
Methods A multielectrode radiofrequency catheter (15 W/60 s) treated 8 renal arteries (group 1). Arteries and kidneys were harvested 7 days post-treatment. Renal norepinephrine (NEPI) levels were correlated with ablation zone geometries and neural injury. Nerve and ganglion distributions and sizes were quantified at discrete distances from the aorta and were compared with 16 control arteries (group 2).
Results Nerve and ganglia distributions varied with distance from the aorta (p < 0.001). A total of 75% of nerves fell within a circumferential area of 9.3, 6.3, and 3.4 mm of the lumen and 0.3, 3.0, and 6.0 mm from the aorta. Efficacy (NEPI 37 ng/g) was observed in only 1 of 8 treated arteries where ablation involved all 4 quadrants, reached a depth of 9.1 mm, and affected 50% of nerves. In 7 treated arteries, NEPI levels remained at baseline values (620 to 991 ng/g), ≤20% of the nerves were affected, and the ablation areas were smaller (16.2 ± 10.9 mm2) and present in only 1 to 2 quadrants at maximal depths of 3.8 ± 2.7 mm.
Conclusions Renal denervation procedures that do not account for asymmetries in renal periarterial nerve and ganglia distribution may miss targets and fall below the critical threshold for effect. This phenomenon is most acute in the ostium but holds throughout the renal artery, which requires further definition.
This study was supported in part by a National Institutes of Health grant (R01 GM-49039) to Dr. Edelman and research grants from Cordis/Biosense Webster, Inc., a Johnson & Johnson Company, to CBSET. Drs. Mahfoud and Böhm are supported by Deutsche Hochdruckliga und Deutsche Gesellschaft für Kardiologie; were investigators of the SYMPLICITY HTN-1 and -2 trials; and received research grants, speaker’s honorarium, and/or consultancy fees from Medtronic/Ardian, St. Jude Medical, Boston Scientific, and/or Cordis. Ms. Fuimaono is an employee of Cordis/Biosense Webster, Inc., a Johnson & Johnson Company. Dr. Böhm is supported by Deutsche Forschungsgemeinschaft (KFO 196). All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Received April 26, 2014.
- Revision received July 1, 2014.
- Accepted July 7, 2014.
- American College of Cardiology Foundation