REFERAT HIPERTENSI RENOVASKULAR

Oleh:

OctafianiNurul Mahirah Bt Moh

Ika Triayunika1

Hipertensi

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Klasifikasi Etiologi Hipertensi• Primary/Essential Hypertension (95%)

• Secondary Hypertension (5-10%)– Renal – GN, RAS, Renin tumors– Endocrine – Cushing, Thyrotoxicosis Myxdema,

Pheochromocytoma, Acromegaly.– Vascular – Coarctation of Aorta, Aortic insufficiency.– Neurogenic – Psychogenic, Intracranial pressure,

olyneuritis etc.

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Hipertensi Renovaskular (HRV)

Epidemiologi:• US: 1-10% of the 50 million—hypertension• Indonesia:

Prevalensi HRV – 2% persen dari seluruh pasien hipertensi– 40-60% pada populasi hipertensi refrakter dengan

pengobatan lebih dari 3 macam anti-hipertensi dan pada populasi di atas 70 tahun

– usia dibawah 30 tahun dan di atas 55 tahun.4

Hipertensi Renovaskular (HRV)

• Stenosis arteri renalis : suatu keadaan terdapatnya lesi obstruktif secara anatomik pada arteri renalis,

• HRV adalah hipertensi yang terjadi sebagai akibat fisiologis adanya stenosis arteri renalis

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Hipertensi Renovaskular (HRV)

• Diagnosis HRV penting karena kelainan ini potensial untuk disembuhkan dengan menghilangkan penyebabnya yaitu stenosis arteri renalis

• Biasanya stenosis lebih dari 70% konsekuensi fisiologis

• Penting untuk membedakan kedua keadaan ini, oleh karena adanya stenosis arteri renalis tidak selalu menimbulkan hipertensi

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Diagnosis Hipertensi

Renovaskular

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Penyebab HRV

1. Lesi Aterosklerotik Arteri Renalis : 70-90% kasus

2. Displasia Fibromuskular :10-20%– Fibroplasia medial– Fibrodisplasia perimedial– Lesi Adventisia

3. Penyebab-penyebab Lain

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Hipertensi Renovaskular (HRV)

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Histologi pembuluh darah

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Aterosklerosis

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Aterosklerosis

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String of beads is the classic radiographic finding seen in FMD

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Pathophysiology Renovascular Hypertension

Pathophysiology Renovascular Hypertension – Unilateral RAS

1. High renin, low volume2. High/normal renin,

elevated plasma volume

3. Irreversible parenchymal HTN

There seems to be three phases of There seems to be three phases of hypertension seen in patients with hypertension seen in patients with unilateral RAS:unilateral RAS:

PathophysiologyRenovascular Hypertension – Unilateral RAS

Irreversible parenchymal HTN:– Prolonged exposure to high BP

and high levels of ATII causes widespread arteriolar damage and glomerulosclerosis in the contralateral kidney.

– This is likely why RVH secondary to ARAS does not resolve after revascularization

.– Hughes et al showed that

corrective surgery for unilateral RVH was successful in 78% of those with HTN of less than 5 years duration but in only 25% of those with HTN of a longer duration.

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PathophysiologyRenovascular Hypertension – Bilateral RAS

• Much less is known about the mechanisms of RVH in bilateral RAS.

• The overall picture is a mixed one, with both renin and volume factors playing a role.

• Evidence suggests there is an increase in effective circulating blood volume owed to elevated aldosterone levels and a blunted pressure naturesis effect.

PathophysiologyIschemic Renal Disease

• Several reversible, adaptive changes occur in response to chronic renal ischemia:– Structural renal atrophy– Diminished cortical blood flow – Reduction in GFR in order to

decrease oxygen demand• Hypertrophy of the contralateral

kidney • Hyperfiltration occurs in the

functional nephrons of the non-effective kidney, which leads to glomerulosclerosis.

PathophysiologyIschemic Renal Disease

• It is very difficult to reliably delineate to what degree renal insufficiency is due to adaptive changes vs. irreversible parenchymal disease

Gambaran klinis

• Anamnesis : – nyeri perut atau pinggang disertai timbulnya

hipertensi, – hipertensi mendadak pada penderita dibawah

umur 30 tahun atau diatas umur 50 tahun,– timbulnya “ accelerated hypertension “ pada

penderita diatas 60 tahun, – Hipertensi yang tidak berespon terhadap obat,

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Gambaran klinis

– pernah mengalami CVA atau tromboemboli sebelumnya,

– tidak ada riwayat hipertensi dalam keluarga,– memburuknya fungsi ginjal setelah diterapi

dengan ACEI dan merokok.

• Pada pemeriksaan fisik – dicari terdengarnya bising vaskuler ( bruit ) di

daerah perut atau kostovetebral.

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Diagnosis

• tes seleksi (screening test)– Pyelografi intravena– Aktivitas Renin Plasma– Renogram hippuran

• tes penentu (confirmative test) – Arteriografi ginjal.– Magnetic Renosance Angiography (MRA).

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Screening pada: • Hipertensi yang timbul pada usia kurang dari 30 tahun

atau lebih dari 50 tahun.• Hipertensi akselerasi atau hipertensi maligna.• Hipertensi yang resisten dengan pemberian 3 atau

lebih macam obat antihipertensi.• Hipertensi dengan gangguan fungsi ginjal yang tidak

dapat dijelaskan sebabnya.• Perburukan fungsi ginjal dari pasien hipertensi yang

diobati dengan ACEI atau ARB.• Hipertensi dengan bising pada abdomen.• Hipertensi dengan oedem paru yang berulang.

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Diagnosis

TesSensitivita

s

Spesifisit

as

Renogram 75% 75%

Renogram kaptopril 83% 93%

Aktivitas renin plasma perifer 57% 66%

Aktivitas renin plasma perifer sesudah pemberian

kaptopril96% 55%

Ultrasonografi

Lesi apapun

Lesi > 60%

95%

90%

90%

62%

Magnetic resonance angiography 88%-95% 94%

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Diagnosis

Conventional Angiography of ARASMRA of ARAS

CT angiography of ARASConventional angiography of FMD

Penatalaksanaan

• Tujuan:mengurangi angka morbiditas dan mortalitas akibat

peningkatan tekanan darah dan iskemia ginjal

obat antihipertensi revaskularisasi dengan angioplasti atau operasi

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• Fibromuskular displasia tindakan revaskularisasi (definitif)

• renovaskular aterosklerotik: revaskularisasi+ obat antihipertensi

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Pengobatan medikamentosa

• ACEI atau ARB.• Indikasi: stenosis unilateral di mana ginjal

kontralateral berfungsi baik; • KI: stenosis arteri renalis bilateral atau

stenosis unilateral pada pasien dengan hanya satu ginjal (yang stenotik)

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Pembedahan

• Angioplasti perkutan• Revaskularisasi dengan Tindakan Bedah

– lesi ostial aterosklesotik aortorenal endarterectomy dan aortorenal bypass.

– lesi fibromuskular graft dari arteri hipogastrika. – lesi aterosklerotik dan lesi fibromuskular

aortorenal vein bypass graft pada

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Terima Kasih….

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Pathophysiology• Renal blood flow is 3 to 5 fold greater than the perfusion to other

organs because it drives glomerular capillary filtration. Both glomerular capillary hydrostatic pressure and renal blood flow are important determinants of the glomerular filtration rate (GFR).

• In patients with RAS, the GFR is dependent on angiotensin II and other modulators that maintain the autoregulation system between the afferent and efferent arteries and can fail to maintain the GFR when renal perfusion pressure drops below 70-85 mm Hg. Significant functional impairment of autoregulation, leading to a decrease in the GFR, is not likely to be observed until arterial luminal narrowing exceeds 50%.

• RVHT develops as a result of increased renin and angiotensin II levels causing vasoconstriction as well as salt and water retention (volume expansion) due to increased aldosterone level.

Pathophysiology• Increased secretion of renin accelerates the conversion of angiotensin I to angiotensin II which enhances the adrenal release of aldosterone.

• Angiotensin II causes vasoconstriction of both afferent and efferent arterioles, with a preferential affect on the efferent side. Under physiologic conditions, efferent tone is essential to maintain intraglomerular pressure.

• In a kidney rendered ischemic by RAS with a reduced afferent blood flow, the intraglomerular pressure and glomerular filtration are maintained by angiotensin II–mediated efferent vasoconstriction. Removal of the efferent vasoconstriction effect by using angiotensin blockade (e.g. by using ACEI) may reduce GFR by causing decrease in intraglumerular pressure.

• In patients with RAS, the chronic ischemia produces adaptive changes in the kidney that are more pronounced in the tubular tissue. These changes include atrophy with decreased tubular cell size, patchy inflammation and fibrosis, tubulosclerosis, atrophy of the glomerular capillary tuft, thickening and duplication of the Bowman capsule, and intrarenal arterial medial thickening.

DiagnosisCaptopril Renography

DiagnosisRecommendations

• The diagnostic work up of RVH or IHD should proceed as follows: • Evaluation of RVH:

– If the patient has normal renal function, the first test should be ACEI renography or Doppler US, based on the local experience and equipment.

– If this test is positive, an anatomic study should be performed to confirm the diagnosis, if intervention is being considered.

• Evaluation of IRD:– Doppler US is the test of choice if local expertise adequate followed by a

more definitive study to delineate the anatomy if intervention is being considered.

– If not: 1. CTA/conventional angiography should be performed if RI is mild2. MRA if RI is moderate/severe or due to diabetic nephropathy

DiagnosisFunctional studies

Diagnostic StudyDiagnostic Study ProsPros ConsCons

Renal Vein Renin MeasurementsRenal Vein Renin Measurements Useful in confirming the functional Useful in confirming the functional significance of a lesion demonstrated significance of a lesion demonstrated by anatomical studies – particularly if by anatomical studies – particularly if bilateral disease is presentbilateral disease is present

Poor sensitivityPoor sensitivity

Nonlateralization not predictive of Nonlateralization not predictive of the failure of HTN to improve with the failure of HTN to improve with therapytherapy

Nuclear Imaging with TcNuclear Imaging with Tc9999-MAG or -MAG or TcTc9999-DTPA to estimate fractional flow -DTPA to estimate fractional flow to each kidneyto each kidney

Allows calculation of single kidney Allows calculation of single kidney GFR and/or RBFGFR and/or RBF

Difficult to differentiate reversible Difficult to differentiate reversible from intrinsic diseasefrom intrinsic disease

Conventional RenographyConventional Renography Useful as both a screening test and Useful as both a screening test and functional studyfunctional study

Lower sens/spec compared to ACEI Lower sens/spec compared to ACEI renographyrenography

ACEI RenographyACEI Renography Test of choice for the diagnosis of Test of choice for the diagnosis of RVH in many centersRVH in many centers

Reduced sens/spec in patients with Reduced sens/spec in patients with renal insufficiency (Prenal insufficiency (Pcrcr>2.0)>2.0)

Operator dependentOperator dependent

DiagnosisAnatomic Studies

“If you’re searching for a lesion, look at the vessel.”Diagnostic Study Pros Cons

Renal ArteriographyRenal Arteriography Gold standardGold standard

Can visualize accessory vessels Can visualize accessory vessels and intrarenal branches welland intrarenal branches well

Direct contrast load to kidneysDirect contrast load to kidneys

Sometimes difficult to distinguish Sometimes difficult to distinguish between critical and non-critical between critical and non-critical lesionslesions

Doppler ultrasonographyDoppler ultrasonography NoninvasiveNoninvasive

Inexpensive; widely availableInexpensive; widely available

Extremely operator dependentExtremely operator dependent

Does not evaluate accessory Does not evaluate accessory vessels wellvessels well

Bowel gas patterns/Obesity Bowel gas patterns/Obesity interfereinterfere

CT angiographyCT angiography Excellent visualization of the vessel Excellent visualization of the vessel in 3Din 3D

High-contrast requirementHigh-contrast requirement

Less reliable for visualizing distal Less reliable for visualizing distal segments and small accessory segments and small accessory arteriesarteries

MRAMRA NoninvasiveNoninvasive

Provides excellent imagesProvides excellent images

Non-nephrotoxic, thus useful in Non-nephrotoxic, thus useful in patients with renal insufficiencypatients with renal insufficiency

ExpensiveExpensive

Prior stents produce artifactsPrior stents produce artifacts

Blood flow turbulence can Blood flow turbulence can exaggerate measured stenosisexaggerate measured stenosis

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Work-upLaboratory Studies:• Serum creatinine and creatinine clearance.• 24-hour urine protein: Vascular renal disease is associated with minimal-to-

moderate degrees of proteinuria, which are rarely in the nephrotic range.• Urinalysis shows absence of red blood cells or red blood cell casts (a hallmark of

glomerulonephritis).• Serologic tests for SLE or vasculitis should be performed if these conditions are

suggested (e.g. antinuclear antibodies, C3, C4, antinuclear cytoplasmic antibodies).

• Measurement of plasma renin activity: The baseline plasma renin activity is elevated in 50-80% of patients with RVHT.

• Captopril test: Measuring the increase in the baseline plasma renin activity 1 hour after the administration of 25-50 mg of the ACE inhibitor (captopril) can increase the predictive value of baseline plasma renin activity. Patients with RAS have an exaggerated increase in baseline plasma renin activity, perhaps due to the removal of the normal suppressive effect of high angiotensin II levels on renin secretion in the ischemic kidney.

• Renal vein renin ratio ≥ 1.5 between stenotic/contralateral kidney are of considerable value in determining functionally important lesions and predicting cure or improvement of HTN with PTA or surgical intervention (although PTA or surgery will also benefit one-third to half the patients without lateralizing renal vein renin ratios).

Imaging Studies • Ultrasound/Duplex ultrasound: Renal US may show significant asymmetry of

kidney size (i.e. size discrepancy of >1.5 cm). Additionally, US may be useful to determine the presence of a solitary kidney. Duplex ultrasound scanning is a noninvasive diagnostic technique that combines a B-mode ultrasound image with a pulse Doppler unit to obtain flow velocity data. It is noninvasive, relatively inexpensive, and can be used in patients with any level of renal function.

• Captopril renography: Radionuclide renal imaging can be done using Tc99m DTPA, Tc99m MAG3 or OIH ( orthoiodohippuran). It is a safe and noninvasive way to evaluate renal blood flow and excretory function. When captopril is administered (especially in unilateral RAS), the GFR of stenotic kidney falls by about 30% and the normal kidney exhibits an increase in the GFR. Sensitivity of this test is about 85-90% and specificity of 93-98%. Significant azotemia and bilateral RAS adversely affect this accuracy, making it unsuitable for these situations.

• CT angiography (Spiral CT): This technique involves the use of IV iodinated contrast material and allows 3-dimensional reconstruction images of the renal arteries. Spiral CT is a useful technique that avoids arterial catheterization and produces accurate images of renal artery anatomy.

Imaging• Renal arteriography: This technique remains the gold

standard for the confirmation and identification of renal artery occlusion in persons with IRD. Specialists can perform renal arteriography by conventional aortography, intravenous subtraction angiography, intra-arterial digital subtraction angiography (DSA), or carbon dioxide angiography.

• Conventional aortography produces excellent radiographic images of the renal artery.

• It is, however, an invasive procedure that requires an arterial puncture, carries the risk of cholesterol emboli, and uses a moderate amount of contrast material with the risk of contrast-induced acute tubular necrosis (ATN).

• Low osmolar contrast material can limit the risk of CEN.

Flush aortogram in a 32-year-old man with familial hypercholesterolemia and difficult-to-control hypertension. Radiograph shows a complete occlusion of the right renal artery and marked stenosis of the left renal artery.

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Clinical findingsof ARAS

DiagnosticEvaluation

UnilateralARAS

BilateralARAS

MedicalManagement

MedicalManagement

Evidence ofIrreversible disease?

InvasiveTreatment

PTRAS

MedicalManagement

Surgery

Evidence ofIrreversible DiseaseRI >80Slow prog. RIProteinuriaSevere atrophy

Progression of RF or uncontrolled HTN

YesNo

Uncontrolled HTN

Low preoperative Risk

High vasc. disease burden

Poor surgical candidate

Predictors of operative mortalityAge >70Unstable CHFAdvanced RIDiabetes

Medical Management

Strict BP control

Antiplatelet angents

Goal LDL < 100

Screening for progression of ARAS