Current status and future perspectives of renal Current status and future perspectives of renal stenting and renal denervation:stenting and renal denervation:

Who is still indications for renal arteries stenting?Who is still indications for renal arteries stenting?

Tadeusz PrzewłockiTadeusz Przewłocki

PINC in Kraków 1411th Peripheral Interventions Workshop

8-9 May 2014

Institute of Cardiology – Collegium Medicum,Jagiellonian University, John Paul II Hospital

Kraków

Renal artery stenosis (RAS)-frequencyRenal artery stenosis (RAS)-frequency

PAOD patientsPAOD patients30 – 45 %30 – 45 %

Harding et al.J Am Soc Nephrol 1992, 2, 1608Harding et al.J Am Soc Nephrol 1992, 2, 1608Olin et al.. Am J Med. 1990, 88, 46Olin et al.. Am J Med. 1990, 88, 46

General populationGeneral population0,1 – 1 %0,1 – 1 %

Hypertensive patients Hypertensive patients 2 – 5 %2 – 5 %

CAD patientsCAD patients10 – 34 %10 – 34 %

Hypertensive patients with renal insufficiency

30 – 40 %

RAS – renal ischemia, RAA- activationRAS – renal ischemia, RAA- activationConsequencesConsequences- - HA, LV hypertrophy, vascular HA, LV hypertrophy, vascular

remodeling, accelerated atherosclerosis remodeling, accelerated atherosclerosis

Heart failureHeart failure Pulmonary oedema Pulmonary oedema

nephropathynephropathy ESRDESRD

strokestroke CAD – MI , UACAD – MI , UA aortic dissectionaortic dissection

cardiaccardiac

renalrenal

vascularvascular

The impact of RAS on survivalThe impact of RAS on survival

Goals for renal revascularization in RAS patients

1. Preservation of renal function2. Improved blood pressure control3. Prevention of CHF or angina pectoris

Survival improvementQOL improvement

Kaltra P, Zeller T. - Salford & Bad Krozingen – 220 chKaltra P, Zeller T. - Salford & Bad Krozingen – 220 ch

Balloon PTA Stenting

EMMA

SNRASCG

DRASTIC

ASTRAL

STAR

ASPIRE 2

RENAISSANCERENAISSANCE

RAS vs BMT – results of randomized trials

No difference

Better hypertension control

CORAL

8 randomized trialsonly 2 positive (in respect of hypertension)

What is „significant renal artery stenosis”?

Physiological stenosis assessment

How to explain discrepancy between observationalinvestigations and randomized trials?

Rest Pd/Pa ratio <0,90 is assoc. with increasedrenin production

Ratio is more import.than gradient alone

Gradient of the systolic blood pressure over 20 mmHg and over 10 mmHg of the mean blood pressure impacts on the physiology of renal blood flow

Renal Fractional Flow Reserve (RFFR)Renal Fractional Flow Reserve (RFFR)

RFFR = Qmax stenosis / Qmax normal

Qmax normal = (Pa-Pv)/ R

Qmax stenosis = (Pd-Pv)/ R

Measurements must be taken at maximal hyperemia.

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 arterial bed dilators

NTG – 0,3 – 1 mg – intrarenally (Gross, Beregi) RBF mean increase 40%

Papaverine – 8 – 40 mg intrarenally (Subramanian, De Bruyne)RBF mean increase 50%

Dopamine – 50ug/kg – intrarenally (De Bruyne) RBF mean increase 95%

In contrast to coronary arteries best renal dilators occureddopamine De Bruyne at al.

FFR Guided Renal Angioplasty

Mean Hyperemic GradientMean Hyperemic GradientR

esp

on

de

rs %

>20m

m H

g

<20m

m H

g0

100

Hyperemic mean gradient >20mmHg (dopamine) independent predictor of blood pressure control improvement after RAS

Blood Pressure RespondersBlood Pressure RespondersImprovement: BP < 140/90 mmHg, or a decrease of DBP by 15 mm Hg on the same or reduced # of medications.

< .80RFFR<0,80

In summary it seems we have two ways of physiological stenosis assessment:

Gradient - across the lesion – resting or hyperemic>20 mmHg(De Bruyne, Massoud, Trana),

Pd/Pa ratio - resting - <0,9 (De Bruyne)hyperemic (RFFR)<0,8 (Mitchell, De

Bruyne,),

Renal FFR of <0.80 predicts an increased Renal FFR of <0.80 predicts an increased

likelihood of BP response.likelihood of BP response.

Renal artery stenosis – criteria for interventionRenal artery stenosis – criteria for intervention

Clinical arterial hypertension(IIa)-resistant, malignant, accelerated failed 3 drugs in max dose

renal dysfunction - severe, progressive – bilateral stenosis solitaire kidney (IIa), unilateral stenosis (IIb)heart failure-unexpected recurrent pulmonary oedema (IC)CAD - recurrent instability episodes (IIa)

Anatomic

stenosis >70 % diameter stenosis or >85 % area reduction - 50-70 % with a peak gradient >20 mmHg

- RFFR<0,80renal length difference ł 1,5 cm or documented decrease > 1 cm

but renal length should be > 7,5 cm