RENAL ARTERY INTERVENTION Robert Lager, MD Cardiology Associates Washington Hospital Center

Robert Lager, MD Nothing to disclose

Renal Artery Stenosis 1-5% of hypertension 5-15% renal dysfunction (ischemic nephropathy) In patients with atherosclerosis—20-30% prevalence Atherosclerosis and fibromuscular dysplasia

Renal Artery Stenosis Complex interaction of anatomic and physiologic mechanisms HTN Renal dysfunction Pulmonary edema ACE intolerance

Challenges of RAS Redundancy

Challenges of Renal Artery Intervention Paired system Define “renal function” (creatinine, 1/sCr, GFR) Asymptomatic Other etiologies mimic the disease Variable progression (30-60% at 4-7 years)1 Risks of intervention Pohl et al, Am J Kiney Dis. 1985;5(4):A120

Understand the disease=Understand the techniques Atherosclerotic RAS 80-90% of all cases Disease of the aorta Male>Female Older age Refractory, progressive Renal dysfunction HTN CHF ACE intolerance

Understand the disease=Understand the techniques Fibromuscular Dysplasia 5-10% of cases Disease of the media Women>>Men Younger age New onset, rapid progression HTN PRE POST PTA

Fibromuscular Dysplasia 5-10% of cases Disease of the media Women>>Men Younger age New onset, rapid progression HTN

Diagnostic Angiography Non-selective abdominal aortography Location and orientation of the ostia Accessory renal arteries Disease of the aorta Adjacent atherosclerosis Calcification Aneurysm

Diagnostic Angiography LAO 20 Lt Left Right

Angiography Injection Non: 15 cc/sec, usually 15-25 cc of contrast Selective: Dilute 70/30, 50/50, 2-6 cc per injection Watch for damping DSA if can control breath hold Shallow ipsilateral angulation Show the nephrogram

Lateral take-off

Diagnostic Set-Up: Catheters

Inferior take-off

Diagnostic Set-Up: Catheters RC 2 HK 1 Contra 2 SOS Omni Inferior take-off

Take it or leave it? Gradient Perfusion guided Serum markers Catheter based (4 vs 5 French) Systolic gradient > 20 mm, Mean > 10 mm Hg Perfusion guided renal frame count, blush grades, nuclear Serum markers BNP, renin FFR guided (baseline, hyperemia with papavarine)

FFR and Renin Debruyne et al, JACC. 2006 vol 48, 9 Stenotic kidney Aorta Debruyne et al, JACC. 2006 vol 48, 9

Hyperemic FFR 32 mg IR papaverine FFR < 0.80 more predictive of BP response Mitchell JA. Cath Cardiovas Int 2007. 69:685-89

Hyperemic systolic gradient HSG>21 mm FFR<0.9 IVUS >67% QRA>60% Leesar M JACC 2009:53 2363-71

Medical Therapy Only???? Moderate RAS->treat medically (over 40% < 70% stenosis) Hypertension vs “ischemic nephropathy”

Intervention Decisions Route of access Catheters/Wires Anticoagulation Engagement approach Embolic protection Complications

Route of Access

Route of Access Most still transfemoral, BUT consider brachial or radial for: Inferior take off Severe infra renal disease AAA PVD Radial: Shorter patients (<160 cm)—Right radial, 110-125 cm catheters Taller (most) patients—Left radial, higher stick

Radial access

Guiding catheters Usually 6 French, unless heavy calcification

Anticoagulation Pre-treatment: Plavix and ASA In-Lab: Heparin (ACT goal 250 sec) Abciximab? Platelet rich emboli

Abciximab Abciximab reduced the occurrence of platelet rich emboli in filter aspirates from 42% to 7% Cooper et al, Circ. 2008 117:2752-60

Engagement Direct engagement Telescope Exchange No-touch

Direct Engagement Pressure Damping, no reflux

Exchange Method 4/5 Fr diag Guide 0.014” wire

Telescope Method 4/5 Fr diagnostic 6/7 Fr guide

No Touch 0.035” wire Guide 0.014 “ wire

Stenting technique Monitor for back pain Cross wire Undersize Balloon Seat guide Pull Back guide Cover ostium Flare ostium

Visualization Can you see the ostium? Must pull back the guide to deploy the stent Use non-angiographic landmarks Image the predilation balloon Rotate gantry while balloon inflated to least foreshorten

Visualization

Stents Palmaz blue, Herculink, Formula, Express Balloon expandable Usually 4-7 mm in diameter All 6 French guide compatible 0.014” or 0.018”Rx 80/135-142 cm shaft length Size 1:1 Cover the ostium Assure adequate post –dilation

Embolic Protection

Embolic protection--Rationale 10-20% worsen peri-procedurally Ischemic nephropathy Evidence of macroembolic particulate material in 60% or greater of cases in multiple studies Mechanisms include Platelet rich emboli Cholesterol emboli (inflammatory response) Contrast nephropathy

Embolic protection--Problems No filter specifically designed for the renal artery Diameter Early bifurcations to the segmental arteries Landing zone Pore size NO RANDOMIZED TRIAL TO SHOW BENEFIT

EPD-Single Center 63 patients Age 70 (54-86) Filter based EPD (most were Angioguard) 60% filters contained debris 6 months: 97% stabilization or improvement 16 months: 94% stabilization or improvement Holden , Hill A, Jaff MR, et al. Kidney Intl 2006

Slow the progression Holden , Hill A, Jaff MR, et al. Kidney Intl 2006

Filter choices Fibernet 40 um pore size 1.5 cm landing zone 3-7 mm diameter Aspirate on removal

Complications Dissection Thrombosis Perforation (avoid hydrophilic wires!) Peri-nephric hematoma Atheroembolic Contrast injury

Dissection

Thank yOU