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

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

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

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

An Issue of Relevance: CMS Coverage Neumann NEJM Feb 2010

Federal Government Review

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 www.ahrq.gov 2006 www.effectivehealthcare.ahrq.gov/reports/final.cfm

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

Clinical Benefit: ‘Reasonable and Necessary’? 277 patients 55% with no clinical benefit ASPIRE + Renaissance Trials 19% MACE at 9 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

The Challenge: “Moving Beyond the Stenosis”

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

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

Renal Fractional Flow Reserve Pa 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)

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

HSG≥21 Improved DBP/SBP at 3-12 mos.

What is the threshold for renin release? De Bruyne, B. et al. J Am Coll Cardiol 48, 1851-5 (2006).

Mean Distal Aortic/Distal Renal Pressure De Bruyne, B. et al. J Am Coll Cardiol 48, 1851-5 (2006).

Angiographic % stenosis= 51-74% 0.9 =25 mm Hg Systolic Pressure Gradient Mean Gradient De Bruyne, B. et al. J Am Coll Cardiol 48, 1851-5 (2006).

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