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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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RVH: ARAS .anaement '(ontd)
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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RVH: ARAS .anaement '(ontd)
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$es
A'RT'RFGA2 4NASS
atients ,ith a healthy abdominal aorta
Mith a free raft of autoenoushypoastric artery or saphenous vein
olytetraKuoroethylene aortorenalbypass rafts
RFGA2 FG9ARTFRFT'.N utili&edoccasionally to treat atheroscleroticrenal artery disease55
O i h i
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Operati%e Techni0$es
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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Operati%e Techni0$es
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