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

2. Robert Lager, MD
Nothing to disclose

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

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

5. Challenges of RAS
Redundancy

6. 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

7. 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

8. 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

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

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

11. Diagnostic Angiography
LAO 20 Lt
Left
Right

12. 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

13. Lateral take-off

14. Diagnostic Set-Up: Catheters

15. Inferior take-off

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

17. 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)

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

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

20. Hyperemic systolic gradient
HSG>21 mm
FFR<0.9
IVUS >67%
QRA>60%
Leesar M JACC 2009:

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

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

23. Route of Access

24. 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, cm catheters
Taller (most) patients—Left radial, higher stick

25. Radial access

26. Guiding catheters
Usually 6 French, unless heavy calcification

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

28. Abciximab
Abciximab reduced the occurrence of platelet rich emboli in filter aspirates from 42% to 7%
Cooper et al, Circ :

29. Engagement
Direct engagement
Telescope
Exchange
No-touch

30. Direct Engagement
Pressure Damping, no reflux

31. Exchange Method
4/5 Fr diag
Guide
0.014” wire

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

34. No Touch
0.035” wire
Guide
0.014 “ wire

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

36. 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

37. Visualization

38. 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/ cm shaft length
Size 1:1
Cover the ostium
Assure adequate post –dilation

39. Embolic Protection

40. 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

41. 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

42. 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

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

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

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

46. Dissection

47. Thank yOU