RENAL ARTERY STENOSIS-An Update-

DR.W.A.P.S.R.WEERARATHNAREGISTRAR-WD 10/02

Objectives

Renal artery Stenosis(RAS) –an overview RAS & Renovascular hypertension-

Pathophysiology Clinical presentation Evaluation & diagnostic modalities Current clinical evidence Management options- current

reccomendations Summary References

RAS-an overveiw

Mainly 2 types- 1. Atherosclotic reno vascular

disease(ARVD) 2.Fibromuscular dysplasia (FMD)

<10% Two common clininical syndromes- 1. Hypertension 2. Ischaemic nephropathty

FMD Affects media in >90% Cause-unknown ?genetic/?smoking/?hormonal/?disorders

of vasa vasarum Female>male, common in 15-50 years Common in distal 2/3 of renal

artey/branches Angiography-beading/aneursyms Progressive dissection/thrombosis

common in intimal & periaoric types

ARVD 90% Usually osteal/proximal 1/3 of main renal

artery/perirenal aorta Ischaemic

nephropathy-segmental/diffuse Increased prevalence- advanced

age/DM/aoroto-iliac disease/CAD/HTN ARVD-5 years after diagnosis progressive stenosis 51% total occlusion 3-16% renal atrophy 21%

(60% occlusion)

RAS pathophysiology-Interrelation among Renal-Artery Stenosis, Hypertension, and Chronic Renal Failure.

Safian RD, Textor SC. N Engl J Med 2001;344:431-442.

RAS & Renovascular hypertension

Renovascular HTN-accelarated/malignant NOT readily distinguishable from

Essential HTN Classic features- (none have

significant predictive value!) Hypokalemia Abdominal bruit Absence of family H/O HTN Duration of HTN < 1 year Onset of HTN < 50 years

Majority of Renovascular HTN have Essential HTN

HTN usually persist despite revascurization!

Reverse tachyphylaxis- sustained HTN redused plasma Renin levels (limitations in measuring plasma renin levels in patients with Renovascular HTN)

Progressive Atherosclerosis, Renal-Artery Stenosis, and Ischemic Nephropathy.

Safian RD, Textor SC. N Engl J Med 2001;344:431-442.

RAS-Pathology/Histology

Angiographic Appearance of the Two Most Common Forms of Renal-Artery Stenosis.

Safian RD, Textor SC. N Engl J Med 2001;344:431-442.

Narrowing of an accessary renal artey…..

Clinical Findings Associated with Renal-Artery Stenosis.

Safian RD, Textor SC. N Engl J Med 2001;344:431-442.

Evaluation of RAS

Noninvasive/ invasive modalities May include studies to asses Overall RFT Asses RAAS Perfusion studies-differential

renal BF Imaging studies- to asses RAS

Noninvasive modalitise

Measuring the response of RAAS-more useful in younger patients with FMD(HTN is renin dependent than in elderly with ARVD! & likely to be cured by revascularization!)

Renin –Na+ profiling Assesment of (Renin) before / after

captopril Assesment of effect of BP/RFT of an ACEI Captopril renography-diffential renal

perfusion cont…

Elderly with ARVDimaging is prefferd!

Duplex ultrasonography-assesment of Renal arteries/BF velosities/pressure wave forms

MRA- Gd enhanced Renal arteries/aorta

CTA- (Gd usually not toxic/exclude if eGFR

<30 )

Invasive modalities

Contrast enhanced angiography- To confirm the diagnosis To detect cause of RAS To evaluate the extent of intrarenal

vascular disease To determine the dimentions To identify associate

aneurysms/occlusive disease of aorta Intraarterial DSA- low volume of contrast

medium needed & no worsening of RFT.

Noninvasive Assessment of Renal-Artery Stenosis.

Safian RD, Textor SC. N Engl J Med 2001;344:431-442.

Algorithm for Evaluating Patients in Whom Renal-Artery Stenosis Is Suspected.

Safian RD, Textor SC. N Engl J Med 2001;344:431-442.

Mangement-ACCF/AHA Guidelines publishedin 2013/March

Medical treatment-class 1 ACE inhibitors are effective medications

for treatment of hypertension associated with unilateral RAS. (Levelof Evidence: A)

Angiotensin receptor blockers are effective medications for treatment of hypertension associated with unilateral RAS. (Level of Evidence: B)

Calcium-channel blockers are effective medicationsfor treatment of hypertension associated with unilateral RAS. (Level of Evidence: A)

Beta blockers are effective medications for treatment of hypertension associated with RAS. (Level of Evidence: A)

Indications for revascularization-

Asymptomatic stenosis -class 2 B Percutaneous revascularization may be

considered for treatment of an asymptomatic bilateral or solitary viable kidney with a hemodynamically significant RAS. (Level of Evidence: C)

The usefulness of percutaneous revascularization of an asymptomatic unilateral hemodynamically significant RAS in a viable kidney is not well established and is presently clinically unproven. (Level of Evidence: C)

Hypertension-class 2a Percutaneous revascularization is

reasonable for patients with- Hemodynamically significant RAS and accelerated hypertension, Resistant hypertension, Malignant hypertension,

Hypertension with an unexplained unilateral small kidney

Hypertension with intolerance to medication

Preservation of renal functions

Class 2A Percutaneous revascularization is

reasonable for patients with RAS and progressive chronic kidney disease with bilateral RAS or a RAS to a solitary functioning kidney. (Level of Evidence: B)

Class2 B Percutaneous revascularization may be

considered for patients with RAS and chronic renal insufficiency with unilateral RAS. (Level of Evidence: C)

Endovascular treatment for RAS

Class1 Renal stent placement is indicated

for ostia atherosclerotic RAS lesions that meet the clinical criteria for intervention. (Level of Evidence: B)

Balloon angioplasty with bailout stent placement if necessary is recommended for fibromuscular dysplasia lesions. (Level of Evidence: B)

Endovascular stenting in RAS

Impact of RAS on CCF& UA Class 1 Percutaneous revascularization is indicated for

patients with hemodynamically significant RAS and recurrent, unexplained congestive heart failure or sudden, unexplained pulmonary edema-Flash pulmonary oedema. (Level of Evidence: B)

Class 2A Percutaneous revascularization is reasonable

for patients with hemodynamically significant RAS and unstable angina. (Level of Evidence: B)

Surgery for RAS

Class1 Vascular surgical reconstruction is

indicated for patients with fibromuscular dysplastic RAS with clinical indications for interventions (same as for percutaneous transluminal angioplasty), especially those exhibiting complex disease that extends into the segmental arteries and those having macroaneurysms. (Level of

Vascular surgical reconstruction is indicated for patients with atherosclerotic RAS and clinical indications for intervention, especially those with multiple small renal arteries or early primary branching of the main renal artery. (Level of Evidence: B)

Vascular surgical reconstruction is indicated for patients with atherosclerotic RAS in combination with pararenal aortic reconstructions (in treatment of aortic aneurysms or severe aortoiliac occlusive disease).

Refferences..

ACCF/AHA Practice guide line-Management of patients with Peripheral atrerial Diseases(compilation of 2005 &2011 ACCF/AHA guide line reccomendations)

NEJM-Renal-Artery Stenosis- Robert D Saflan & Stephan C Textor MD NEJ MED 2001