1. Renal artery interventions
Aravinda Nanjundappa, MD RVT
West Virginia University

2. Aravinda Nanjundappa, MD
DISCLOSURES
Aravinda Nanjundappa, MD
Consulting Fees
Cardiva Medical, Inc.
Honoraria
Novartis AG, Bristol-Myers Squibb/Sanofi Pharmaceuticals Partnership

3. Patient Preparation Antiplatelet Hydration/Bicarb
ASA and Clopidogrel at least 5-7 days
Hydration/Bicarb
N-acetylcysteine, if renal insufficiency
600 mg bid
Visipaque® for high risk patient

4. Abdominal Angiography
Renal arteries usually originate at the L1 level
The side-holes of the catheter are positioned at the T12-L1 interspace
Use digital subtraction angiography (DSA) and inject a total of 15 cc (1:1) of contrast at rate 15 ml/sec

5. Abdominal Aortography

6. Non-selective Abdominal Aortogram
Exclude presence of accessory RA
Demonstrate disease of the aorta (eg., atheroma, AAA, dissections, etc)
Identify origin of the RA’s
Facilitate placement of diagnostic catheter and guide catheter
Avoid unnecessary “windshield wiping”/”helicoptering” in aorta of selective catheters

7. Cholesterol embolization

8. RA’s arise posterolateral off aorta
LAO 20° Lt Rt Lt
RA’s arise posterolateral off aorta

9. Angles make make a big difference
AP View
20° LAO View

10. Common Femoral approach

11. Cobra
JR 4
IMA
AR 1
Lateral take-off

12. RC 2
HK 1
Contra 2
SOS Omni 2
Inferior take-off

13. Sos-Omni Engagement

14. Brachial approach
Iliac or aortoiliac disease
Downward take off RA’s

15. Selective Angiography
5/6 French
Insist on backflow and no pressure damp before injecting
Contrast
(Dilute by 50:50)
2-6 cc per injection with good reflux
DSA helps minimize contrast

16. Interventions

17. Equipments 5/6 Fr diagnostic catheter 7-Fr, 55 cm RDC guide catheter
JR4, IMA,
7-Fr, 55 cm RDC guide catheter
0.014-inch wire (I like sport wire)
Predilate balloon (primarily stent?)
3-4 mm x 20 mm
Balloon expandable stent
5-7 mm
?covered stents (e.g.iCast)
Role of embolic protection
IVUS guided- minimizes contrast

18. Guiding Catheter IM
RDC
RDC 1

19. Medication Unfractionated Heparin - 50 units/kg (ACT 200-250 sec)
No post procedure heparin is routinely required.

20. Techniques for guide engagement
Direct engagement
Telescoping technique
Exchanged technique
No touch technique

21. Direct engagement

22. Don’t inject if pressure damp

23. Telescoping technique
Preload diagnostic through rotating hemostat valve and guide cath, advance over wire to renal

25. Exchange technique
0.018 guidewire

27. No touch technique

28. Renal Stenting TechniqueB C D E F
Monitor pain during balloon inflation

29. Stent Size and Restenosis rates
Reference Vessel Diameter, mm
Restenosis Rate, %

30. EPD for Renal artery Interventions

31. Courtesy, Leonardo Clavijo, MD PhD

32. Rationale for the use of EPD in renal interventions
Approximately 25% of patients undergoing renal artery intervention (RAI) have improvement in renal function, 50% stabilization, and 25% deterioration
10-20% incidence of procedure related deterioration
Pre-intervention planning has only been modestly successful (e.g, BNP, renal artery flow reserve, age/lesion type, etc.) in predicting success

33. Mechanisms of deterioration in renal function post renal intervention
Contrast
Distal embolization
Obstruction to flow and renal infarction (but, with normal renal function, up to 50% of nephron mass may be lost without change in Cr)
Inflammatory response from cholesterol emboli
Increased ESR
Urinary eosinophils

34. Mechanisms of deterioration in renal function post renal intervention
Reperfusion injury?
natural history of the parenchymal disease
Restenosis
Limiting the emboli may allow for increased clinical success
Should be combined with meticulous technique throughout the procedure

35. Ex vivo renal artery model created
33 intact aorto-renal atheroma casts from 17 patients who underwent renal artery endarterectomy
Ex vivo renal artery model created
Effluent collected after each manipulation
Analyzed for particles size and number
Hiramoto J. J Vascular Surg 2005

36. Particles <100 micrometers that are released.
>100 micrometers released during PTA with stent.
(Efferent arteriole approximately 20 microns)
Hiramoto J. J Vascular Surg 2005

37. Does it work? 63 patients Age 70 (54-86) Filter based EPD
6 months: 97% stabilization or improvement
16 months: 94% stabilization or improvement
60% filters contained debris
Holden , Hill A, Jaff MR, et al. Kidney Intl 2006.

38. Does it work? Henry, et al 124 renal interventions Distal occlusion-
Distal occlusion balloons- 46
Filters- 78
Distal occlusion-
Mean occlusion time min
debris collected in 100%
#13-208/procedure
micometers (mean )
Atheroma, cholesterol crystals, fibrin, thrombi (fresh- 10% cases & organized), foam cells, macrophages, platelets, lipoid masses
Filter-
Mean deployment time min
80% collection
6 month follow up 1.1% deterioration
2 year follow-up 3% deterioration

39. Available EPD for Renal Interventions
(none approved)
Filter based systems
May not have enough landing zone- resulting in only one branch being filtered (though debris not preferentially shunted)
Filter can clog/thrombose
Distal balloon occlusion systems
Inadequate distal landing zone means that only one branch is protected and debris is preferentially shunted to unprotected parenchyma
Warm ischemia
Proximal occlusion
Not feasible since the majority of lesions are aorto-ostial or proximal

42. Henry M, et al. Expert Rev Cardiovasc Therapy 2005

43. Conclusions Renal artery stenosis is a technically demanding procedure
Most lesions are aorto-ostial
?role for EPD
?primary stenting
?covered stents

44. Thank you