SEMINAR ON TREATMENT OF RAS

1. Seminar on Treatment of
Renal Artery Stenosis
DR. ABID KUCHAY
DM RESIDENT NEPHROLOGY

2.  Renal-artery stenosis, defined as a narrowing of one or both renal arteries
or their branches
 Spectrum-
asymptomatic RAS
Renovascular hypertension
Ischemic nephropathy
Unstable cardiac syndromes

6.  CAUSES
 Atherosclerosis related RAS (>90%)
 Fibromuscular dysplasia
 Less commonly
 Takayasu
 Coarctation of aorta
 Atheroembolic disease
 Renal compression (page kidney etc)

8. How common is RAS ?
 Variable degree of renal artery stenosis - 19% to 42% of patients with
atherosclerotic vascular disease of other vascular beds
 Fibromuscular dysplasia - 3% to 5% of healthy patients evaluated as
potential living kidney donors.
 mild to moderate hypertension, 0.6% to 3% of population.
 In patients with refractory hypertension - 10% and 45% of patients

9. Who should be screened for renal artery stenosis?
• Abrupt onset of HTN at a relatively young age (30 yrs ) or older age (>50
yrs)
• Worsening control of previously well treated hypertension
• Recurrent episodes of “flash pulmonary edema”
• Kidney failure ppt by initiation of antihtn therapy—esp. ACEi or ARBs
• Unexplained kidney failure Unilateral atrophic kidney
• Abdominal bruit • Unexplained hypokalemia

10. Goals of Diagnostic Evaluation
 Establish presence of renal artery stenosis: location and type of lesion
 Establish whether unilateral or bilateral stenosis (or stenosis to a solitary kidney) is
present.
 Establish presence and function of stenotic and nonstenotic kidneys
 Establish hemodynamic severity of renal arterial disease
 Plan vascular intervention: degree and location of atherosclerotic disease

11.  Non invasive imaging:
 Duplex ultrasonography
 measures flow velocity as a means of assessing the severity of stenosis
 Peak systolic velocity > 180cm/sec & relative velocity >3.5 as
compared to adjacent aorta
 Sensitivtiy and specificity of angiographically doc >60 % lesions can
surpass 90 and 96 percent respectively
 Resistivity index – relative velocity in diastole & systole in segmental
afrteries
 Above 80 identifies renal parenchymal disease that didn’t respond
favourably to revascularisation

12.  CT Angiography:
 images renal arteries and perirenal aorta
 Sensitvity and specificity 98% and 94% respectively
 Nephrotoxicity due to contrast administration
 MRI-
 Sensitivity 83-100% specificity 92-97 %
 Unable to visualise stented vessels
 Risk of nephrogenic fibrogenic dermopathy esp GFR <30ml/min

13. Invasive imaging
 Digital subtraction Intraarterial angiography –gold standard
 Contrast induced nephrotoxicity

14.  Physiologic Studies to Assess the Renin Angiotensin System
 Plasma renin activity- limited value in clinical decision making
 Measurement of renal vein renin levels –
Helps in Lateralization ( ratio exceeding 1.5 between the renin activity of
stenotic & nonstenotic kidney)
planning surgical revascularization for hypertension

15.  Split renal function measurements
 radionuclide techniques using radioisotopes (e.g., technetium 99m–
labeled mercaptoacetyltriglycine [99mTc-MAG3] or technetium 99m–
labeled diethylenetriaminepentaacetic acid [99mTc-DTPA]) estimates
fractional blood flow and filtration to each kidney.
 Administration of captopril beforehand magnifies the effect.

17. Treatment
Goals of therapy
 Improved blood pressure control
 Preservation of renal function

18.  Fibromuscular Dysplasia
 treatment of choice for FMD is percutaneous renal artery angioplasty (PTRA)
usually without stenting.
 Primary technical success rates are high (>90%)
 Complete cure, defined as normalization of BP without need for medications,
occurs in 35% to 45% of cases.

19.  Predictors of response to intervention include
 lower preintervention systolic BP,
 younger age,
 shorter duration of hypertension, and
 positive pretreatment captopril renogram

20.  Inadequate initial treatment or restenosis seen in 34% of treated cases
 most common with string of beads angiographic variant
 intimal and adventitial variants - higher rates of PTRA failure
 require surgical revascularization
 Women of childbearing age with RA aneurysms should be treated before pursuing
pregnancy ; risk for rupture

21. Trinquart et al.,2010; Olin and SeaLove ,2011 ; Plouin et al 2007

22.  Atherosclerotic renal artery stenosis
 medical management,
 angioplasty/stent placement,or surgery

23.  Medical management:
 Antihypertensives,
 ACEI/ARBs (1st line)
 Beta blockers (2nd line)

24.  aspirin,
 statins,
 smoking cessation, and
 good glycemic control in patients with diabetes.

25.  Revascularisation:
 Surgical revas- assigned to history
 Following 1990,PTRA with stenting (PTRAS)-bare metal stents
 Target vessel patency rates using PTRS exceeds 95%.
 However ,efficacy of PTRAS compared to medical therapy consistently failed to
prove added advantage

27. BP levels and the proportion of patients given antihypertensive
treatment were similar one year after randomization in the control
and angioplasty groups,”

28. 135 eligible patients , of whom 55 (44%) were randomised.
Eligible patients had sustained hypertension, with a minimum DBP >95 mm Hg on at least
two anti-hTN drugs.
Unilateral: PTRA: 173/95 Med Rx: 161/88
Bilateral: PTRA: 152/83 Med Rx: 171/91 (P < 0.01)
 No patient was ‘cured’,
 renal function did not improve, and
 intervention arm - significant complication rate.

29. NEJM 2000
N = 106 ASO RAS > 50%
Resistant: 2 drugs DBP > 95 mm Hg or creatinine rise with ACEI
BP outcomes at 3 mo: PTRA: 169/89 Med Rx: 163/88
At 12 mo: PTRA: 152/84 Med Rx: 162/88 No. drugs: 1.9 vs. 2.4 (P < 0.01)
“In the treatment of patients with hypertension and renal artery stenosis,
angioplasty has little advantage over antihypertensive drug therapy”

30. All of these trials had limitations of
 short time frames,
 high (29% average) crossover rate, and
 small cohorts
hence, lacked power to adequately determine differentiation.

31. efficacy and safety of stent placement
in patients with ARAS and impaired renal function.
STAR
2009

32.  Randomized clinical trial
 10 Europeancenters ( 9 in Netherlands & 1 in France)
 The primary end point was a 20% or greater decrease in creatinine
clearance.
 Secondary end points included safety and cardiovascular morbidity and
mortality

34. Results
 Ten of the 64 patients (16%) in the stent placementgroup and 16 patients (22%) in
the medication group reached the primary end point (hazard ratio, 0.73 [95% CI,
0.33 to 1.61]).
 Serious complications occurred in the stent group, including 2 procedure-related
deaths (3%), 1 late death secondary to an infected hematoma, and 1 patient who
required dialysis secondary to cholesterol embolism.
 The groups did not differ for other secondaryend points

35. randomized, unblinded trial,
806 patients with ARV disease either to undergo revascularization
in addition to receiving medical therapy or to receive medical
therapy alone.
2009

36.  primary outcome was renal function, as measured by the reciprocal of the
serum creatinine level (a measure that has a linear relationship with
creatinine clearance).
 Secondary outcomes were blood pressure, the time to renal and major
cardiovascular events, and mortality.
 median follow-up - 34 months

39. CONCLUSION
 substantial risks but no evidence of a worthwhile clinical benefit from
revascularization in patients with ARVD

40. Objective:usefulness of stenting for the prevention of major adverse renal
and cardiovascular events is uncertain.

41.  randomly assigned 947 participants who had ARAS and either systolic hypertension
while taking two or more antihypertensive drugs or chronic kidney disease to
medical therapy plus renal-artery stenting or medical therapyalone.
 Participants were followed for the occurrence of adverse cardiovascular and renal
events (a composite end point of death from cardiovascular or renal causes,
myocardial infarction, stroke, hospitalization for congestive heart failure,
progressive renal insufficiency, or the need for renal-replacement therapy).
 median follow-up period of 43 months

43.  CONCLUSION
 Renal-artery stenting did not confer a significant benefit with respect to the
prevention of clinical events when added to comprehensive, multifactorial medical
therapy in people with atherosclerotic renal-artery stenosis and hypertension or
chronic kidney disease.

45.  Novel markers and interventions
 Brain natriuretic peptide
 Hibernating parenchyma (MR-perfusion imaging & BOLD MRI)
 Brachytherapy
 Renal artery denervation
 VEGF
 Endothelial cell progenitors

46.  TRANSPLANT RENAL ARTERY STENOSIS (TRAS)
 common post-transplantation complication; BTW 3 months and 2 years
 Incidence -1.3% to 23%
 more common in deceased donor
 allografts with multiple renal vessels, and
 pediatric kidneys in adult recipients

47. Pathophysiology
 atheromatous disease in the donor artery,
 intimal scarring, and hyperplasia in response to trauma to the vessel
during harvesting,
 Anastomotic stenosis, esp. with end-to-end anastomoses , suture
technique.
 Other proposed pathogenic mechanisms include CNI toxicity and CMV
infection.
 atherosclerotic disease (pseudo–transplant RA stenosis)

48. Presentation
 new-onset or worsening hypertension with or without decline in allograft
function
 pseudo–transplant RA stenosis - ipsilateral lower extremity claudication with
hypertension and worsening function in the allograft
 Risk factors include
 male gender,
 diabetes mellitus
 hyperlipidemia,
 smoking,

49.  Renal duplex ultrasound -screening test of choice
 sensitivity and specificity - 90% to 100% and 87% to 100%, respectively.
 MRA provides excellent anatomic definition but is associatedwith clip
artifact at the anastomosis and high false-positive rates.
 CTA is comparable to renal arteriography , large amount of contrast
material

50.  PTRA with or without stenting
 Surgical renal revascularization of allografts ;difficult and associated with
high complication rates.

 Complications include
 graft loss (in 15% to 30% of cases),
 ureteral injury (14%), and
 death (5%).

51. Thank you