1. Renal CTA: Can We Determine Who Will Benefit from RAS
Renal CTA: Can We Determine Who Will Benefit from RAS? Krishna Rocha-Singh, M.D., FACC, FSVM, FSCAI Director, Prairie Vascular Institute Springfield, IL

2. Krishna Rocha-Singh, M.D.
Research
Abbott Vascular
Consultant/Advisory Board/Training
Cordis
Medtronic
ev3, Inc.
Royalties/Financial Interest
None
VIVA Board Member
Medical Director PERC, salary
I will discuss off-label use of vascular devices

3. Renal Artery CTA: Can We Predict Clinical Responders?
Review role of non-invasive RA imaging modalities to identify POTENTIAL BP responders
Consider the role of angiography and trans-lesion gradients to identify clinical BP responders
Discuss evolving role of FFR in predicting clinical BP responders

4. The Dilemma of RAS The Patient Renal Physiology
Angiographic % Stenosis
The Patient

5. An Issue of Relevance: CMS Coverage
Neumann NEJM Feb 2010

6. Federal Government Review

7. AHRQ Conclusions:
Most importantly: PTRA with stent v. aggressive medical therapy:
There is no published evidence directly comparing angioplasty with stent placement and “aggressive” medical treatment with currently available drugs for ARAS
Overall, the evidence does not currently support one treatment approach over the other for the general population of people with ARAS
Notably, almost two-thirds of the studies were of poor methodological quality
2006

8. BP Improvement after RAS (50-70% DS Visual Estimate)
50%

9. Clinical Benefit: ‘Reasonable and Necessary’?
277 patients 55% with no clinical benefit
ASPIRE + Renaissance Trials
19% MACE at months
The decision to perform a renal intervention must carefully weigh the potential benefits of improved blood pressure control and renal function preservation against possible complications and procedure related costs.
BENEFIT
RISK

10. The Challenge: “Moving Beyond the Stenosis”

11. Lack of Correlation: Angiography & Clinical Outcomes
How Severe are These Ostial Renal Artery Lesions? What is Your Visual Estimate?

12. RA Angiographic %DS & Visual Assessment: A Weak Link….
N=17 Refractory HTN >140/90
%DS: No correlation with BP response, TPG did not correlate with BP response
Subramanian CCI 2007

13. Renal Fractional Flow ReservePa Pd Pv
Qmax stenosis = (Pd-Pv) / R
Pa = mean aortic pressure
Pd = mean pressure distal to stenosis
Pv = mean central venous pressure
Qmax normal = maximum renal blood flow
in the absence of stenosis
Qmax stenosis = maximum renal blood flow
in the presence of stenosis
R = renal arteriolar vascular resistance at
maximum hyperemia
Renal FFR = Renal Fractional Flow Reserve Pd Pa
Renal FFR = Qmax Stenosis / Qmax normal = Pd -Pv / Pa - Pv
Renal FFR = Pd / Pa (Assuming the central venous pressure is zero)

14. Assessed (n=62)
RA %DS
IVUS area
TPG
HSG
FFR

16. HSG≥21 Improved DBP/SBP at 3-12 mos.

19. What is the threshold for renin release?
De Bruyne, B. et al. J Am Coll Cardiol 48, (2006).

20. Mean Distal Aortic/Distal Renal Pressure
De Bruyne, B. et al. J Am Coll Cardiol 48, (2006).

21. Angiographic % stenosis= 51-74% 0.9 =25 mm Hg
Systolic Pressure Gradient
Mean Gradient
De Bruyne, B. et al. J Am Coll Cardiol 48, (2006).

22. Take Home Message:
Patient selection and their clinical milieu deserves our added attention: resistant HTN
Angiographic (visual )assessment of lesion severity is a poor predictor of clinical response
Renal physiologic assessment deserves more attention as a potential predictor of blood pressure improvement