Medtronic Cardiovascular, Preclinical Insights Into the Optimal Ablation Location for Renal Denervation Procedures Robert J. Melder, ScD Senior R&D Director Medtronic Cardiovascular, Santa Rosa, CA Authors: Robert J. Melder, Stefan Tunev, Jennifer Ruwart, Paul Coates, Julie Trudel, Daniel Schulz-Jander and Martin Rothman

Disclosure Statement of Financial Interest Within the past 12 months, I or my spouse/partner have had a financial interest/arrangement or affiliation with the organization(s) listed below. Affiliation/Financial Relationship Company Grant/Research Support Consulting Fees/Honoraria Major Stock Shareholder/Equity Royalty Income Ownership/Founder Intellectual Property Rights Other Financial Benefit (Employee) None Medtronic Inc.

Historical Review of Past Performance: Review of 66 treated and 64 Naïve Swine Mean 291+ 88 N = 238 Average of four RF ablations in each artery Significant (P<0.05) increase in non-functional axonal area along artery Significant drop (P<0.05) in sympathetic axonal density measured by immuno-histochemistry in the renal cortex Significant drop (P<0.05) in tissue norepinephrine (NE) values measured in the renal cortex Catheter-based Renal Denervation has a significant impact on sympathetic nerve function and viability but with substantial variability

Our view of renal nerve distribution has changed: Can we do better with new methodological approaches to denervation with the existing technology? Renal nerves may have a positional bias : distal nerves are closer to the arterial lumen Histological analysis by Sakakura1 and others2,3 suggest that a more distal approach could increase the frequency of successful ablations Distal ablation strategies can be executed with the existing catheters 2 mm radial intervals per ring 1Sakakura K et al. J Am Coll Cardiol. 2014 Aug 19;64(7):635-43. 2Tzafriri ARJ Am Coll Cardiol. 2014 Sep 16;64(11):1079-87. 3Mahfoud F EuroPCR2014

Experimental Approach Part 1: Main Renal Artery Dose Response Hypothesis- Increasing the net ablative dose of RF by increasing number of lesions will increase the degree of renal nerve ablation Method- Three treatment arms of animals were randomized for unilateral RDN treatment with Symplicity Spyral in the Main Renal artery using 1, 2 or 3 treatment cycles, producing 4, 8 or 12 lesions in the treated artery The contra-lateral kidney was used as the “in-animal” control Study terminated at 7 days and tissues sampled for histology and renal NE analysis Part 2: Distal Main and Branch Treatment Hypothesis- Focusing treatment on the most vulnerable segments of renal artery will provide an optimal ablative response Method- Two treatment arms of animals were randomized for unilateral RDN treatment with Symplicity catheters; Spyral was used to treat only the renal artery branches (1 cycle), Flex was used to treat only the Distal Main artery (6 lesions) The contra-lateral kidney was used as the “in-animal” control Study terminated at 7 days and tissues sampled for histology and renal NE analysis

Renal Tissue Norepinephrine Analysis 4 lesions 8 lesions 12 lesions 4 lesions/ branch 6 lesions All treatments significantly reduced tissue NE No meaningful dose response to multi-cycle Spyral treatment could be observed in the Main Renal Artery Branch and Distal Main treatments showed decreased variability

A closer look at response: Greater levels of NE reduction with increased uniformity of response Branch treatment reduced mean tissue NE by 84% with 2 outliers Distal Main treatment with reduced Mean tissue NE by 84%, also with 2 outliers but most values near zero 47% Decrease 84% Decrease 84% Decrease

Renal Tissue Analysis – Cortical Axon Density 4 lesions 8 lesions 12 lesions Treatments closely paralleled renal NE response No meaningful dose response to multi-cycle Spyral treatment could be observed in the Main Renal Artery Branch and Distal Main treatments showed decreased variability

A closer look at response: Greater levels axon reduction with increased uniformity of response Branch treatment reduced mean axon area by 82% Distal Main treatment reduced mean axon area by 88% 40% Decrease 82% Decrease 88% Decrease

I V Y Optimization of the Treatment Methodology: a combined target approach to renal denervation I RF treatment of the Main Artery V RF treatment of each Branch Y RF treatment of the Main Artery and Branches

Branch & Main Artery Treatment Highly Effective in Reducing Renal NE Untreated or undertreated branches can give rise to outliers (red circle) in response Combination treatment of renal artery branches and main artery seem to be optimal in reducing outlier impact 2-cycles of treatment in the main artery do not improve response more than 1 cycle of treatment

Histology of Branch Treatment (near branch point) Dotted lines=RF injury areas, arrows=necrotic nerves in RF area, arrowheads=intact nerves, M=psoas muscle, V=vein, U=ureter, Ad=adrenal gland, Cr=cranial edge Necropsy and histology indicate Branch Artery and Main Renal Artery treatment appear to show similar safety profile as conventional RF treatment in the main artery with minimal non-target involvement

Summary Prior experience with renal denervation responses in swine indicates that the placement of the lesions may be a source of variability in the response Histological analysis of human renal arteries suggests that zones of closest approach of renal nerves to the renal artery provide ideal ablation sites Increasing the number of ablations along the main renal artery reduces variability of response but not does not significantly increase the degree of renal nerve ablation Targeted renal nerve ablation in zones of nearest approach (distal main and branches) can maximize the denervation response Treating the renal artery branches in combination with the main renal artery significantly increases the net amount of nerve ablation and decreases the variability of the response Treating the renal artery branches and main renal artery shows a similar safety profile as conventional treatment in the main artery, although clinical confirmation of the safety and efficacy of this approach is needed