Download Renal-Artery Stenosis

Clinical Practice
Renal Artery Stenosis
Lance D. Dworkin, M.D., and Christopher J. Cooper, M.D.
November 12, 2009
2010년 3월 23일 화요일
신장내과 R4 이완수
Case Vignette
• Age/Sex
– 73/male
• Chief compliant
– shortness of breath
 ER visit
• Personal History
– former smoker
• Past History
– Hypertension
– Dyslipidemia
• Vital sign
BP 160/75 mmHg
HR 60 beats/min
RR 24 breaths/min
• Physical Examination
Chest auscultation - diffuse rales
Pitting edema (1+)
• Lab.
Serum Creatinine 1.4 mg/dL
(eGFR 52ml/min)
Urinalysis protein 1+
Case Vignette
• Condition improves after treatment (IV diuretics)
• But, systolic BP remains elevated (170 mmHg)
• Magnetic resonance angiography (MRA)
– diseased aorta
– Lt. renal artery (ostial lesion)
 High grade “atherosclerotic stenosis”
– Rt. renal artery  normal
Renal artery stenosis (Lt.)
• How should he be further evaluated and treated?
Outline
• The Clinical Problem
• Strategies and Evidence
– Evaluation
– Treatment Options
• Medical Therapy
• Surgical Therapy
• Angioplasty and Stenting
• Areas of Uncertainty
• Guidelines
• Conclusions and Recommendations
The Clinical Problem
• “Renal-artery stenosis”
• Definition
– narrowing of one or both renal arteries or their branches.
• Cause
– 1. atherosclerosis (most common, 90%)
– 2. fibromuscular dysplasia (Less frequently)
– 3. other causes (rare)
•
•
•
•
•
•
•
Vasculitis (Takayasu’s arteritis)
Dissection of the renal artery
Thromboembolic disease
Renal artery aneurysm
Renal artery coarctation
Extrinsic compression
Radiation injury
• Characteristics of Atherosclerotic Renal-Artery
Stenosis and Fibromuscular Dysplasia
Effective Tx.?
controversial
balloon angioplasty
• Prevalence
– atherosclerotic renal artery stenosis in CKD – 0.5~5.5%
– true frequency maybe higher
(∵ often asymptomatic)
• Anatomical progression
– occur in more than one third of patients
– But, one study
• 5 yrs F/U, “Stenosis”  “Occlusion “
• only 3~15% patients treated medically
• conducted before statin therapy was available
Medical treatment is important!!
• Pathogenesis
RAS : renal artery stenosis
RBF : renal blood flow
• Other vascular event?
– Renal-artery stenosis ( HTN, CKD)
 increased risk for vascular events
chronic kidney disease (25%, vs 2%)
coronary artery disease (67% vs 25%)
stroke (37% vs 12%)
peripheral vascular disease (56% vs 13%)
– Explanation?? Uncertain
•
•
•
•
•
concomitant atherosclerosis in other vascular beds
activation of the renin–angiotensin–aldosterone
activation of the sympathetic nervous systems
associated renal insufficiency
all these factors
Strategies and Evidence
•
Classic clinical clues (renal artery stenosis)
1. onset of stage 2 hypertension (BP >160/100mmHg) after 50yrs old
2. family history of hypertension (-)
3. hypertension associated with renal insufficiency
(Esp, RAAS inhibition agent  renal fuction wosens)
4. hypertension with repeated hospital admissions
heart failure
drug-resistant hypertension
(treatment c three drug of different class  BP control fail)
Diagnostic Imaging Tests for Renal-Artery Stenosis
• Once renal-artery stenosis is suspected??
• confirmation of the diagnosis??  imaging!!
∵ biochemical tests (plasma renin concentrations)  specificity ↓
Duplex Ultrasonography in a Patient with Renal-Artery Stenosis
• Excellent tool
non-invasive
no apparent side effects
• Measurement
“renal-artery velocity”
 functional assessment
of the “severity of stenosis”
higher velocity
 greater pressure differential
across the stenosis
• Limitation
abdominal obesity
bowel gas
technically demanding
(not available at all centers)
Magnetic Resonance Angiography
Computed Tomographic Angiography
• High-resolution multislice detector devices
• Elegant images of the renal arteries and the abdominal aorta
• Limitation  may affect image quality
– equipment
– technique
– reconstruction of the images
– patient-related factors
• presence of calcium
• presence of stents
• ability to hold one's breath during imaging
• Caution)
– CKD patients : toxicity of the contrast medium
• nephrogenic systemic fibrosis is associated with gadolinium
• nephropathy is associated with iodinated contrast dye
• Rt. renal aterty (arrow)
70% ostial stenosis
systolic pressure gradient of 28mmHg
• Lt. renal artery (arrowhead)
40% ostial stenosis
pressure gradient of 13mmHg
Magnetic Resonance Angiography of the Renal Arteries Showing Severe Bilateral Stenosis
Digital subtraction angiography
• Best image quality, anatomy information
• use of small-diameter catheters and minimal amounts
of contrast material
reduce the risk of vascular complications and contrast
nephropathy
• Limitation
–
–
–
–
–
–
invasive
only in experienced centers
contrast nephropathy in CKD
atheroembolic event
vascular complication at punture site
Radation exposure
•
•
•
•
degree of atherosclerosis of the aorta
size of the kidney
extent of poststenotic dilatation
rapidity of the appearance and washout of contrast material
Useful in diagnosis of Renal artery stenosis
“Functional significance” of the lesion ?
Predict the “response to revascularzation” ?
No conclusive test
• nuclear scintigraphy
• renin sampling from the renal veins
• pressure gradients across stenoses
Kidney (supplied by an occluded renal artey) is viable?
Contributing to hypertension ?
Stenosis is affecting intrarenal pressure?
Treatment Options
• Medical Therapy
• Surgical Therapy
• Angioplasty and Stenting
 improved survival
improved BP control
less impairment of renal function
Medical Therapy
• Cornerstone of treatment for renal-artery stenosis
• Recommendations
– Multidrug regimens for BP control
– RAAS inhibitor is recommended in most patients
(Renin–angiotensin–aldosterone system is often activated in patients
with renal-artery stenosis)
– alpha-blocker or beta-blocker
– long-acting CCB
– diuretics
•
Caution)
“Bilateral severe stenosis“
Use of “RAAS inhibitor”  ARF
High-grade stenosis in one kidney
Advanced chronic kidney disease
probability of this complication appears to be low
in most cases, it is reversible with the discontinuation of treatment
Medical Therapy
• Recent data
– ACE inhibitor  reduced risk of death
– Statin  reduction in the severity of renal artery
stenosis
– Statin c stenting  improve survival
– Statin, antiplatelet therapy  benefit in patient
with atherosclerotic disease
Surgical Therapy
• Surgical revascularization
– durable relief of renal-artery stenosis
– improves BP control and kidney function
• Safety
– recent data have indicated a 10% in-hospital mortality after this
procedure among Medicare patients
• “balloon angioplasty” vs “surgery”
– 58 patients with renal-artery stenosis, randomized trial
– resulted in similar rates of cure or improvement in HTN, renal
function
“nonsurgical revascularization”  first-line approach
(if an intervention is planned)
Angioplasty and Stenting
• “Fibromuscular dysplasia”
– balloon angioplasty remains the preferred form
 many patients are able to discontinue all antihypertensive
medications
– But, medical therapy alone may be appropriate in patients
with well-controlled hypertension
• “Atherosclerotic renal artery stenosis”
– balloon angioplasty
• Less effective
• Restenosis 71%↑
• 3 multicenter trials, without stenting
– 1 yr follow-up, no significant improvement in BP
• But, controversial
Angioplasty and Stenting
• Predictors of a favorable outcome of angioplasty
– 40 years ↓ at diagnosis
– duration of hypertension <5 yrs
– systolic BP <160 mmHg
Angioplasty and Stenting
• Stents
– limit elastic recoil
– restenosis-free patency ↑
(compared with angioplasty alone)
– BP control ↑after stenting
Angioplasty and Stenting
• Recent trials
– 1. comparing stenting plus medical therapy with medical
therapy alone
• preservation of renal function
• no significant benefits with the addition of stenting
– 2. Angioplasty and Stenting for Renal Artery Lesions (ASTRAL)
• stent revascularization in addition to medical therapy vs
medical therapy alone
• renal function, mean systolic blood pressure, in rates of
renal or cardiovascular events or death
• no significant difference between the study groups at the
5yrs follow-up
Angioplasty and Stenting
– 3. Stenting in Renal Dysfunction Caused by Atherosclerotic
Renal Artery (STAR) trial
• prevention of loss of kidney function
• serious procedure-related complications
• stenting plus medical therapy vs medical therapy alone
• did not show a benefit
Angioplasty and Stenting
• Revascularization
– renin–angiotensin–aldosterone system ↓
– sympathetic nervous system ↓
– possible cardiovascular benefits
 improved survival
improved BP control
less impairment of renal function
“pharmacologic therapy”?? directed at these pathways
 may have similar benefits
Areas of Uncertainty
Response to revascularization?
 no method reliably predicts
Optimal treatment strategy?
“Angioplasty and Stenting” vs “medical therapy alone”
 remains unclear
• Data are lacking
– randomized clinical trials comparing the effects of various medical regimens
• Available data from randomized trials
– not shown a benefit of “revascularization plus medical therapy” with respect
to blood-pressure control and renal function
– But, these trials had methodologic limitations, were not powered for the
assessment of cardiovascular outcomes, and did not include quality-of-life
assessments
Previous algorithm
• Cardiovascular Outcomes in Renal Atherosclerotic Lesions
(CORAL) study
– large, multicenter, randomized, controlled trial
– funded by the National Institutes of Health
– scheduled to be completed in 2011
– medical therapy plus stent revascularization vs medical
therapy alone
– end point : cardiovascular and renal events
– Pending the results of the study
• best treatment for renal-artery stenosis ?
• whether to evaluate ?
 remain uncertain
Guidelines
•
American College of Cardiology–American Heart Association 2005 guidelines
(for the care of patients with peripheral-artery disease, including renal-artery
stenosis)
•
Revascularization recommendations
– class I evidence (i.e., general agreement on usefulness)
• recurrent congestive heart failure
• pulmonary edema
– class IIa evidence (i.e., conflicting opinions, but with the preponderance of
evidence favoring usefulness)
•
•
•
•
•
•
•
•
global renal ischemia
progressive chronic kidney disease
unstable angina
hypertension that is worsening
resistant to medical therapy
malignant
unexplained unilateral small kidney
cannot tolerate antihypertensive medication
Conclusions and Recommendations
•
A diagnosis of renal-artery stenosis should be considered in any patient with a
history of severe or resistant hypertension, hypertension that is associated with
renal insufficiency, or disease in other vascular beds.
Clinical Finding Associated with Renal Artery Stenosis
Hypertension
Abrupt onset of hypertension (age<40)  fibromuscular dysplasia
Abrupt onset of hypertension (age>50)  renal artery stenosis
Accelerated or malignant hypertension
Refractory hypertension (not responsive to therapy c 3≥drugs)
Renal abnormalities
Unexplained azotemia  renal artery stenosis
Azotemia induced by treatment with an angiotensin converting enzyme inhibitor
Unilateral small kidney
Unexplained hypokalemia
Other findings
Abdominal bruit, flank bruit, or both
Severe retinopathy
Carotid, coronary, or peripheral vascular disease
Unexplained congestive heart failure or acute pulmonary edema
Conclusions and Recommendations
• Initial examination
 measurement of kidney function and a lipid profile
• Anatomical diagnosis
– duplex ultrasonography
– CTA or MRA (if high-quality duplex imaging is not available)
• Therapy
– intensive medical therapy
– tight BP control with a blocker of the RAAS
(serum creatinine and potassium should be closely monitored)
– administration of an antiplatelet agent and a statin
– Treatment of diabetes and chronic kidney disease
• Revascularization in the treatment of atherosclerotic renal-artery
stenosis ?
 controversial