renovascular hypertension (rvh)seminar

8/15/2019 Renovascular Hypertension (RVH)Seminar

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Renovascular hypertension

(RVH)DEFINITION

“The presence of systemichypertension due to a stenotic orobstructive lesion within the renalartery”

Form of secondary hypertension,accountin for an estimated !"#$ to

%$ of cases in unselected


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RVH: Introduction

The simultaneous presence of Renal Artery Stenosis(RAS) and systemic hypertension does not establishRenovascular Hypertension

Strictly speakin! the de"nitive dianosis of RVHcan only be made retrospectively &

Hypertension responds to correction of thestenosis


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RVH: Introduction '(ontd)

In practice! obtainin complete#reversal$ or #cure% of hypertension israrely seen

Important to reconi&e thatrenovascular disease:

• 'ften accelerates preeistinhypertension

• an ultimately threaten the viability of

the post*stenotic kidney


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Etiology of Renal Artery

Stenosis

Atherosclerosis

-ibromusculardysplasia

Takayasu’s arteritisPolyarteritis Nodosa

Radiation-induced


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ARAS

.ost common and problematic causeof RVH

/01 of cases of RVH due to ARAS

.ainly in older men2esion at the ostium or proimal thirdof the renal artery as an etension of

an aortic pla3ue4ilateral in appro5 678 of cases


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ARAS '(ontd)

Risk factorsIdentical to those associated ,ithsystemic atherosclerosis! i5e5!

Advanced ae! male se! smokin!9iabetes mellitus! hypertension!

ositive family history! and

9yslipidemia


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ARAS '(ontd)

;enerally believed that

ARAS slo,ly proresses over time! butthe rate of proression is variable (


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-ibromuscular dysplasia

(-.9)-our histoloic variantsreconi&ed:

Intimal *broplasia

True *bromuscular hyperplasia

+edial *broplasia

-erimedial 'subadventitial)*broplasia

They di?er in natural history


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PATHOPHYSIOLOGY

The classical eperiments of ;oldblattlampin of renal arteries in dos canproduce hypertension

T,o models described:

'ne clip t,o kidney

hypertension'ne clip one kidneyhypertension


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;oldblatt 9o .odels

AR47AF inhibitors help 'nly help ,hen Ga depleted


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athophysioloy of RVH

4asic event is renal hypoperfusion Triers release of Rennin from the utalomerular cells

Rennin release is mediated by:

.acula 9ensa (decreased del5 'f l)

• Tubulolomerular feed back

4aroreceptors in a?erent arteriole

Geural mechanismAdrenericStimulation

Fndocrine! aracrine and Autocrinepath,ays


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RVH: athophysioloy '(ontd)


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athophysioloy of RVH

hases of Renovascular Hypertension

.enin dependent hypertension

vs

/olume dependenthypertension

ltimately culminates as FSR9


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RVH: 9ianosis

.ere presence of RAS and

hypertension does not establish thedianosis of RVH

Three*step approach to the dianosis

of RVH has been suested


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RVH: 9ianosis '(ontd)

-irst step:An appropriate selection of patients ,hoare more likely to have RVH

Second step: The patientsJ renal arteries are imaed todemonstrate RAS

Third step:

Resolution or improvement in bloodpressure control occurs ,ith reversion ofthe stenosis


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DIAGNOSIS linical pointers for renovascular

disease in the hypertensivepatient:

0ystolic and diastolic upperabdominal bruits

Diastolic hypertension of 122#mmh

.apid onset of hypertensionafter the ae of #! years

3 sudden worsenin of mild to


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linical pointers (contd5)

4ypertension that is di5cult tocontrol with three or more

antihypertensivesDevelopment of renal insu5ciencyafter 3(E inhibitors

Development of hypertensiondurin childhood"

4ypertension below 6!yrs of ae

in absence of family history of


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9ianosis'vervie,

There are t,o roups of dianostic studies used toevaluate RAS:

Anatomic studies:65 Renal anioraphy @ the old standard

>5 9oppler ultrasonoraphy85 Spiral T anioraphy

=iothalamate or 9TA to

determine ;-R

/5 onventional renoraphy

D5 AFI renoraphy


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RVH: Imain

Intra*arterial anioraphy The old standard

Invasive and carries the risk of contrast*

induced nephropathyGot used routinely unless

oncurrent therapy ,ith anioplasty!,ith7,ithout stentin! is bein considered

9iital subtraction anioraphy'> and adolinium contrasts havebeen tried ,ith ood results


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RVH: Imain '(ontd)

9iital subtraction anioraphy (9SA)ses less dye than a conventionalarterioram but is still invasive

The 3uality of imaes ,ith 9SA is not asood as ,ith conventional anioram


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RVH: Imain '(ontd)

9uple ultrasound imain9irect visuali&ation of the renal vasculartree ,hile assessin blood Ko, velocity

and pressure ,ave forms2imitations include interoperatorvariability and the need for epertise inobtainin and interpretin the imaes


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RVH: Imain '(ontd)

4ased on detectin the altered Ko,pattern distal to the stenosis ,ith aturbulent +et durin systole and adecrease in diastolic Ko,5

.easurements are obtained at theproimal main renal artery usin astandardi&ed anle of incidence


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RVH: Imain '(ontd)

Indices used to dianose stenosis:

-ea7 systolic velocity '-0/) 1 28!

cm9sec 'normal renal -0/ averaes 2!!: ;# cm9sec)"

.enal 3ortic .atio '.3.)1 6"#""

3cceleration Time, 3cceleration Inde


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RVH: Imain '(ontd)

Spiral computed tomoraphyanioraphy

Fnables a three*dimensional

reconstruction of the vascular treeFcellent sensitivity and speci"city tovisuali&e RAS

Ho,ever! re3uires up to 6=0 cc of

iodinated contrast! ,hich may benephrotoic


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RVH: Imain '(ontd)

.anetic resonance anioraphy(.RA)

Goninvasive imain techni3ue and results in ecellentvisuali&ation of the renal vasculature

;adolinium is used as the radio*contrast in the phasecontrast techni3ue

9ra,backs

Hih cost

otential for nephroenic systemic "brosis in patients,ith renal insuLciency


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RVH: Imain '(ontd)

(aptopril>enhanced renoraphy

Goninvasive test and the ability to assess

renal functional statusse is limited in patients ,ith bilateral RASand in patients ,ith sini"cant renalinsuLciency

4ased on loss of AT II mediated e?erentarteriolar constriction

rovide a basis for functional! notanatomical! dianosis of RAS! as there is

no direct visuali&ation of the renal arteries


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RVH: Imain '(ontd

The study is performed in well>hydrated patients with liberal saltinta7e"

3(E inhibitors are discontinued for 6to # days before the study, but otherantihypertensives may be continued

Oral captopril ';# to #! m) is usually

used, althouh I/ enalapril '!"!%m97) can be used as well"

The captopril renoram is obtained 2

hour after the captopril dose.


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RVH: Imain '(ontd

The most commonly used aents aretechnetium ??m ' ??mTc)diethylenetriaminepentaacetic acid'DT-3)

These chanes on the postcaptoprilrenoram include&

a delayed time to ma


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9ianosis-unctional studies

Diagnostic Study Pros Cons

Renal Vein Renin Measurements Useful in confirming the functionalsignificance of a lesion demonstratedby anatomical studies – particularly ifbilateral disease is present

Poor sensitivity

Nonlateralization not predictive ofthe failure of HN to improve !ith

therapy

Nuclear "maging !ith c##$M%& orc##$'P% to estimate fractional flo!to each (idney

%llo!s calculation of single (idney&)R and*or R+)

'ifficult to differentiate reversiblefrom intrinsic disease

,onventional Renography Useful as both a screening testand functional study

-o!er sens*spec compared to %,." renography

%,." Renography est of choice for the diagnosis ofRVH in many centers

Reduced sens*spec in patients!ith renal insufficiency /Pcr 01234

5perator dependent


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9ianosis

Diagnostic Study 6ens2 6pec2 PPV NPV

Renal Vein Renins 718 93$::8

'oppler Ultrasonography :3$#:8 #:8 ##8 ::$#98

,onventional Renography 9;8 :;8


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RVH: .anaement

Treatment options includeharmacoloical therapy ,ith variousantihypertensive medications!

ercutaneous anioplasty ,ith or ,ithoutstent placement! and

Surical revision of RAS


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RVH: .anaement '(ontd)

Availability of potent antihypertensivedrus and the advances inendovascular techni3ues! as ,ell as

stents! have made surical treatmentrarely necessary


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RVH: TA .anaement

4esides manaement of hypertension and itscomplications!

Steroids and immunosuppressive aents likemethotreate and cyclophosphamide are used tosuppress disease activity

Response to therapy is faster and better in children,ith a hiher rate of remission

Anti*platelet aents like aspirin and dipyridamolehave been used especially in patients ,ith transient

neuroloical symptoms


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riteria -or Intervention

Angiography criteriaFibromuscular dysplasia lesion

-ressure radient 1;! mm4

3Aected9unaAected 7idney renin ratio 12"#&2

linical criteriaInability to control hypertension despiteappropriate antihypertensive reimen"

(hronic renal insu5ciency related to bilateralrenal artery stenosis or to a solitaryfunctionin 7idney"

Dialysis>dependent renal failure withoutanother de*nite cause of end>stae renaldisease"


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In patients !i"ro#$sc$larDysplasia inter%ention is g$i&e&

"y the speci'c type of &isease as&eter#ine& "y angiographic'n&ings


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(EDIAL !I)ROPLASIAProgressi%e o"str$ction*loss of renalf$nction is $nco##on

(EDIAL (ANAGE(ENT preferre& initial

treat#entInter%ention reser%e& for refractoryhypertension

INTI(AL or PERI(EDIAL!I)ROPLASIA

Generally progressi%e lea&ing toische#ic renal atrophy. Ten& to occ$r inyo$nger patients

a$se hypertension that is e+tre#ely


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atients ,ith atherosclerotic RVH areolder and often have etrarenalvascular disease5

Therefore more viorous attempts atmedical manaement are ,arranted

.ultiple*dru reimens that controlthe blood pressure are often the

preferred approach5 Indeed! the advent of ne, ande?ective antihypertensive has

enhanced the eLcacy of medical


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Intervention is best reserved forpatients ,hose hypertension cannotbe ade3uately controlled or ,henrenal function is threatened byadvanced vascular disease


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RVH: ARAS .anaement '(ontd)

'ne of the larest trials! The Anioplasty and Stentin for RenalArtery 2esions (ASTRA2) study!

D0C renal failure patients (mean serumcreatinine approimately > m7d2) ,ithatherosclerotic renal vascular diseaseincluded

Randomi&ed to receive either

revasculari&ation and medical therapy ormedical therapy alone


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ASTRA2 Study '(ontd)

'n averae! patients had /=1 RAS

At 6*year follo,*up there ,ere no

di?erences in the chane in serumcreatinine level (it rose by 05> m7d2 inboth roups) or in rates of renal events!includin acute renal failure


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At this time! there is no clear bene"t of revasculari&ation forARAS!

Fspecially in patients for ,hom 4 can be controlled easilyand ,ho have no evidence of ischemic nephropathy

The risks of the procedure may out,eih any potentialbene"ts

Anioplasty ,ith or ,ithout stentin may be of bene"t inatients ,ith HT that is diLcult to control in the settin ofdecreased renal perfusion! because uncontrolledhypertension is a ma+or cardiovascular risk factor

Accordinly! aggressi%e treat#ent of hypertension /ith#e&ications is reco##en&e&


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.odalities Available Mith The Sureon

Surical revasculari&ation procedures

Fndovascular interventionsFRTAGF'S TRAGS2.IGA2

AG;I'2ASTN

FG9'VAS2AR STFGTIG;


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SR;IA2RFVAS2ARIOATI'G

Preoperati%e Preparation@eneral medical condition of the patient isthe main determinant of the ris7

Operative ris7 is minimal in youn patients

with F+DIn atherosclerotic renovascular disease

3(BTE (O.ON3.C E/ENT0 are the leadincause of -E.IO-E.3TI/E +O.T3ITC

3 thorouh evaluation for of coronaryartery disease is indicated

+yocardial revasculariation if indicatedshould precede renal revasculariation"

(erebrovascular accident has also been a

i h i


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Operati%e Techni0$es

A'RT'RFGA2 4NASS

atients ,ith a healthy abdominal aorta

Mith a free raft of autoenoushypoastric artery or saphenous vein

olytetraKuoroethylene aortorenalbypass rafts

RFGA2 FG9ARTFRFT'.N utili&edoccasionally to treat atheroscleroticrenal artery disease55

O i h i


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In older patients severeatherosclerosis of the abdominal aorta

Alternative surical procedures areused:

Splenorenal bypass for left renalrevasculari&ation

Hepatorenal bypass for riht renal

revasculari&ation5eliac ais ostial occlusion must beecluded

Importance of obtainin preoperative

O i T h i


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se of the supraceliac or lo,erthoracic aorta more recent suricalalternative

Reconstruction ,ith an interpositionsaphenous vein raft5

2imited role of total or partialnephrectomy

Severe arteriolar

nephrosclerosis


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FRTAGF'S TRAGS2.IGA2

AG;I'2ASTN -irst introduced by ;rPnt&i in;ermany

9ilatation a renal artery stenosis usina balloon catheter techni3ue

Access is typically via a femoral artery

4rachial approach can be consideredin

Aortoiliac occlusive7aneurysmal disease!

audal renal artery anulation5


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FRTAGF'S TRAGS2.IGA2


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FRTAGF'S TRAGS2.IGA2AG;I'2ASTN

Systemic heparini&ation atheteri&ation of the renal arteryusin anled catheters

A selective renal anioram performed2esion crossed ,ith a 0508=*in or a0506D* to 0506


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FRTAGF'S TRAGS2.IGA2AG;I'2ASTN

4alloon is si&ed to the diameter of thenormal renal artery5

4alloon ,ith a


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FG9'VAS2AR STFGTIG;

Fndovascular stent placement is thetreatment of choice for hih*rade renalartery stenosis

Hih incidence of restenosis ,ith balloon

anioplasty! especially in ostial stenosis5

Stentin is also indicated for renal arterydissection caused by balloon anioplasty

Studies have clearly demonstrated theclinical eLcacy of renal artery stentin,hen compared to balloon anioplastyalone in hih*rade renal artery stenosis


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FG9'VAS2AR STFGTIG;


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FG9'VAS2AR STFGTIG;

Assess balloon and stent lenth anddiameter5

(Hih Quality

Anioram) The stent used should be lon enouhto traverse the entire lesion

Fcessive lenth beyond the lesion isundesirable

In ostial lesions! the stent protrude 6to > mm into the aortic lumen to

prevent restenosis

I di ti 'f St ti


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Indications 'f Stentin

urrent indications for stentplacement are:

oor immediate results durin TA

Restenosis after TA To treat anioplasty complications (arterydissection and intimal Kaps

#rimary$ stent placement is becomin

increasinly popular esp5 In (ostiallesions)5

renovascular hypertension (rvh)seminar

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