How to perform renal denervation

10 Catheter Handle Features Shaft & electrode can rotate independent from handle body • Handle rotator has tactile “click” every 45° • Dot on rotator gives relative rotational referen

How to Perform Renal

Denervation

A/Prof Michael Nguyen

Director Cardiac Catheterization Laboratory

Fremantle Hospital Western Australia

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Overview

• Equipment and lab setup

• Assessing renal anatomy

• Intra-procedural patient management and monitoring

• Symplicity Catheter delivery and RF ablation

• Post-procedural care

• RF Generator messages

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Equipment and Lab Setup

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System™

LBL027 Rev E

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Equipment Set-up

• Symplicity Catheter and Generator

• Dispersive electrode (Ground pad) – sent with Symplicity Catheter

• Non-ionic contrast (dilute to 50:50)

• Heparinized saline flush bag

• Radiopaque ruler (optional)

Common medications to have available:

• Heparin

• Fentanyl / Morphine or similar

• Midazolam (Dormicum, Versed) or similar

• Nitroglycerine

• Atropine

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Generator and Dispersive Electrode

• Generator

– Plug in RF generator and turn on switch on back panel

– Verify system beeps and all displays momentarily illuminate

– Press Continue

• Dispersive Electrode (Ground Pad)

– Place on the thigh or other non-bony area out of the angiogram field (shave if necessary for good contact)

Model G2 Front Panel

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Catheter Handle Features

Shaft & electrode can rotate independent

from handle body

• Handle rotator has tactile “click” every 45°

• Dot on rotator gives relative rotational

reference

Deflect tip by pulling lever

towards back of handle

Straighten tip by pushing lever towards front of handle

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Assessing

Renal Anatomy

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Renal Angiogram

Eligible Anatomy:

• Absence of flow limiting obstructions

• Diameter ≥ 4mm in targeted area

• Absence of prior renal angioplasty, indwelling renal stents,

or aortic graphs

Renal Angiogram

• Limit contrast dye exposure

– 50/50 dilution of contrast and use of DSA or biplane may help

• Verify entire kidney fills with contrast

Accessory Vessel Partially Supplies Lower Portions of the Kidney

Lower Pole Not

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Oblique Angiographic Views

• Changing from AP to oblique and cranial views can provide optimal assessment of artery length

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Guide Catheter Selection

• Once suitable anatomy is confirmed, upsize to 6Fr (or larger) introducer and guide

• Consider guide shape based on renal anatomy

Alternate: IMA or LIMA Typical: RDN-D1 or RDC-1

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Intra-Procedural Patient

Management and Monitoring

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• Anxiolytic and Amnesic

– Midazolam (Dormicum, Versed) or similar recommended, often administered before groin access

• Anticoagulation

– Heparin: target ACT >250 sec

– Continuously flush guide catheter with heparinized saline during the procedure

• Pain Management

– Patients may experience transient visceral pain during each ablation

– Fentanyl or Morphine (or similar) 10-15 minutes before first ablation; as needed thereafter

• Vasodilatation

– IA nitroglycerine through renal guide is recommended before

treating each artery

*The ultimate selection of medications is made by the physician based on individual case

• Fluid resuscitation for hypotension

• Atropine for bradycardia or block associated with hypotension

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Symplicity Catheter

Delivery and RF Ablation

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• Nerves arise from T10-L2

• The nerves arborize around the artery and primarily lie within the adventitia

Targeting Renal Nerves

Vessel Lumen

Media

Adventitia

Renal Nerves

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Targeting Renal Nerves

• Always Treat distal to proximal

• Do not re-cross previously treated sites

• Distal: Inferior and inferolateral locations

• Proximal: Superior and superolateral

locations

• Favor stable wall contact over

circumferential treatment

• PULL, ROTATE, ASSESS new location and

prior treatment site with cine just prior to

each treatment

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Delivering Symplicity Catheter

• Fully straighten tip of catheter AVOID advancing the catheter while the tip is deflected

• Deliver Symplicity Catheter through the renal guide catheter

Use the catheter shaft (not handle) to

position catheter within vessel

Position electrode ≥5mm proximal to renal bifurcation

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Positioning Catheter

• With electrode advanced to most distal treatment site, use handle lever to deflect catheter tip against vessel wall and retract to most distal treatment site

• Good wall contact is important for the proper delivery of energy

– First deflect slightly and rotate to superior or inferior hemisphere

– Fully deflect tip to optimize electrode apposition to the vessel wall

– May not need to use handle lever to deflect tip in tortuous anatomy or proximal locations

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Wall Contact

Sufficient Wall Contact

Excessive Wall Contact

(avoid distending vessel wall with electrode)

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Example Treatment Sites

Because of added guide catheter support, proximal locations may require less deflection to achieve

vessel wall contact

Distal locations in

straight vessels may

require more

deflection to achieve

vessel wall contact

Unable to confirm adequate contact visually (may need to rely on impedance to assess

for sufficient wall contact)

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Optimizing Treatment Sites: Impedance

• Impedance may be used to confirm

stable wall contact:

– Higher impedance may indicate

better wall contact

– In an early superior or inferior

location with good visible wall

contact, note “reference

impedance” for comparison with

– Abnormally high impedance may

indicate electrode is in a

side-branch

* Impedance varies by patient and vessel Care should be taken to notice range of available impedance readings within each vessel

• Fentanyl or morphine (or similar)

• Sufficient anticoagulation (confirm ACT > 250)

• Document each treatment site using cine

• Initiate energy delivery:

– Stabilize catheter – do not move during treatment

– Press foot pedal (or RF button) once to activate catheter

– Do not inject contrast during active treatment (alters impedance)

• Generator will automatically control RF energy delivery:

– Continuously monitors temperature and impedance

– Automatically shuts off after 2 min or when either impedance or temperature exceed program limits

– To manually stop RF delivery, depress foot pedal or press RF button once

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Repeat for Additional Treatment Sites

• Reposition electrode for next treatment:

– Retract Symplicity Catheter proximal

– If needed, straighten catheter tip using handle lever

– Deflect electrode to make contact with vessel wall, using visual and impedance feedback

– Rotate electrode to appropriate treatment location

• Allow ≥ 5 mm between treatment sites ( ~3 electrode lengths)

– Secondary shaft marker may help identify 5mm spacing

– Document treatment site with cine prior to activating catheter

New treatment location

Initial treatment location

≥5 mm (~3 electrode lengths)

Secondary shaft marker

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Switching Sides / Ending Procedure

• Straighten tip, then remove Symplicity Catheter from patient and check catheter tip

• If coagulum or clot are present on electrode, gently wipe with a sterile gauze pad dampened with sterile saline

• Perform renal artery angiogram (cine) of treated artery

• Confirm ACT > 250 sec

• Repeat entire procedure on opposite renal artery

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Areas to Avoid

• Avoid placing the electrode at the ostium of small branch arteries, such as those perfusing the adrenal glands

• Avoid treating in very distal segments of the renal artery, in particular,

segments beyondsignificant renal artery branch

• There is no clinical experience treating near any areas of visible

atherosclerosis, calcification, or fibromuscular dysplasia Avoid treating

areas of visible disease

• There is no clinical experience treating in vessels with renal artery

Avoid treating in segment with stenosis

Avoid energy delivery to area with visible calcification

Avoid treating in segment with FMD

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Post-Procedure Care

• Manage femoral access site per standard protocol

– Be attentive to preventing groin access complications

• Be attentive to radiocontrast nephropathy

prophylaxis per hospital policy (hydrate well)

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RF Generator Messages

Note: This section only applies to G2 generator software version 1.02.01 and beyond

Basic and Advanced Settings

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• Per the Generator User Manual, using softkeys, it is possible to toggle

between Basic and Advanced displays

• During RF ON, in addition to time and temperature, the advanced display also displays Power and % Impedance drop

• Generally, bigger impedance drops indicate better delivery of energy

Summary

• Overview of the Pre-Procedure Preparation

– Correct equipment and lab setup, and knowledge of the Symplicity™ generator and Symplicity™ catheter use are essential components of the pre-procedure preparation

• Detailed Treatment Procedure

– Careful assessment of target sites under angiography, optimization of device delivery, and monitoring intra-procedural patient care can help ensure a successful procedure Remember the Symplicity catheter is intended for single patient use only

• Post-Procedure Care

– In the post-procedure phase, after assessing results under

angiography, the femoral access site should be managed per standard protocols and proper hydration should be provided