a case of bilateral renal artery stenosis

A CASE OF UNEXPLAINED HYPOKALEMIA

Prof.S.Sundar UnitDr.R.Ganesan

PG Internal medicine

History

• Breathlessness-6 hours• No h/o Chestpain• Palpitation• Cough&expectoration• Decreased urine output• Pedaledema• Abdominal distension

• No h/o Facial puffiness• NSAID’S intake• Altered sensorium• Fever• Vomiting• Diarreha

Past history

• No past h/o similar episode• K/C DM-7 years on treatment• Not a k/c SHT/CAD/CKD/COPD• Married,having one daughter• Postmenopausel women• Non smoker,non alcoholic

Examination

• Conscious,oriented• Afebrile• Dyspnic,tachypnic• No pedaledema/ clubbing• No pallor/cyanosis• JVP not elevated

Vitals

• BP-250/150 mmhg• PR-98/m,Vessal wall thickend• RR-38/m• Carotid bruit +

• CVS-S1,S2 + ESM+ in AA• RS -NVBS + B/L basal crepts +• P/A -Soft,no organomegaly, no FF• CNS- NFND

Investigations

• CBC:Hb-10g% TC-6800cells/cmm DC-P55%,L40%,E4% Platelet-2lak/cmm PCV-34%Urea-38mg%,Createnine-0.9mg%RBS-210mg%

• Na-138meq/l, K-3.1meq/l• Urine r/e-normal• Urine ketons-negative• Urine c/s-no growth• 24 H urine protein-310mg•

• Lipid profile:T. CHO-210mg/dl TGL-160mg/dl LDL-155mg/dl HDL-35mg/dl VLDL-20mg/dl

• ECG-Sinus tachycardia• CXR-S/O Pulmonaryedema• ECHO-Mild AS,

Concentric LVH LVEF-60% No RWMA No AR

• ABG-Normal• 24 H urine K-16meq• 24 H urine Ca-30meq

DIAGNOSIS-?

USG KUB

• RK-10×4.5cm,CMD+,normal echo• LK-4×2.8cm,contracted

Renal artery doppler study

RK PSV EDV RIUpper pole

184cm/s 29 0.6

Mid pole 153cm/s 10.3 0.8Mesenchimal.A

186cm/s 22 0.7

LK PSV EDV RI

Upper P 184cm/s 7.3 0.7

Lower P 181cm/s 13.1 0.58

Mesenchimal A

179cm/s 15.5 0.8

64 Slice MD CT-Abdominal angiogram

• Small LK with narrowing of origin and occlusion of left renal artery with distal reformation by retroperitoneal collaterals• Stenosis of origin of Right renal artery• Occlusive calcified atheromatous plaque

of aorta• Multiple lumbar retroperitoneal

collaterals

• Bilateral Renal Artery Stenosis

Treatment

• Back rest• Nasal oxygen 6L/m• Ing.NTG 25micg/m• Ing.Frusemide 100mg stat• T.Amlodepine 2.5mg 4bd• T.Atenolol 50mg 2od• T.Methyldopa 250mg 2tid• T.Prazocin 2mg 2bd

• T.Atarvostatin 10mg 4 HS• HA-8 IU tid• HM-10 IU bed time

DEFINITION

• Syndrome of elevated blood pressure produced by a variety of conditions that interfere with arterial circulation to kidney tissue

TWO KIDNEY HYPERTENSION

• Unilateral ASRVD• Unilateral FMD• Renal artery aneurysm• Renal artery embolism• Traumatic arterial occlusion• Tumor compressing the artery

ONE KIDNEY HYPERTENSION

• Bilateral renal artery stenosis• Stenosis of solitaryfunctioning kidney• Coarctation of aorta• Takayasu’s disease• Polyarteritis nodosa

TAKAYASU’S ARTERITIS

• Most common in Asia• Female to male ratio-9:1• Age of presentation 10-20 years• Strong predilectoin of aortic arch and

it’s branches-AORTIC ARCH SYNDROME

Scenarios in RA stenosis and hypertension

• True RVH• Pure essential hypertension in which RA

stenosis is present but not contribute to hypertension• Essential hypertension with

superimposed RA stenosis in which RA stenosis contribute to essential HT• RA stenosis leads to ischemic renal

disease

CLINICAL FEATURES

• Abdominal bruit• Hypokalemia• Family h/o hypertension-abscent• Early onset<30 years• Late onset>50 years• Flash pulmonary edema

• Nephrotic-range proteinuria• Acute renal failure during

treatment of hypertension• Progressive renal failure

NONINVASIVE SCREENING TESTS

• Magnetic resonance angiography• CT Angiography• Renal duplex sonography

MRA

• Best screening test• Sensitivity 92%-100%• Specificity 69%-95%• Negative predictive value 100%• Over estimate the degree stenosis mid

to distal renal artery• Accessory renal artery may be missed

CT-Angiography

• Similar sensitivity&specificity of MRA• Proven useful in restenosis of

stented renal artery• Requiring intravenous radiocontrast

Renal duplex sonography

Proximal criteria 1.Peak systolic velocity>200cm/sec 2.Ratio of PSV in renal.A to aorta>3.5 3.Turbulent flow in poststenotic

region 4.Lack of detectable doppler signal in

a visualized renal artery

Distel criteria

• Loss of early systolic peak• Slope of the systolic

upstroke<300cm/sec• Acceleratioon time>0.07sec• Resistive index change of >5%

between right&left kidney

RESISTIVE INDEX

RI=[PSV-EDV]/PSV Predict renal function &BP response

to renal revascularisation RI>0.8 poor chance of improvement

• Sensitivity 66%-100%• Specificity 67%-94%• Operator dependency• Patient factors-habitus, echogenisity

of fascia,depth,angle of artery, bowel gas interference

OTHER SCREENING TESTS

• Captopril renography- accurate for RVH but not accurate in renal insufficiency

• Renal vein renin- not useful in bilateral renal disease

• Isotopic renal blood flow and functional scans-not useful in bilateral renal disease

Angiography-GoldstandardTEST CONTRAST ARTERIAL

PUNCTURE

RISK OF EMBOLI

QUALITY OF IMAGE

CONVENTIONAL ++ YES +++ +++

INTRAVENOUS SUBSTRACTION

+++ NO NO +

INTRAARTERIAL SUBSTRACTION

+ YES ++ ++

CO2 NON YES +++ +

MANAGEMENT OPTIONS

• Medical management• PTRA• PTRA with endovascular stent• Primary renal artery stenting• Surgical revascularisation

Medical management

• Optimizing the blood pressure• Treatment of hyperlipidemia• Cessation of smoking• Control of diabetes• Management of CKD• Careful followup at 4-6months intervel

for change in renal function&size

INDICATIONS FOR REVASCULARIZATION

• Uncontroled BP inspite fo maximal drug therapy• Prograssive rise in creatinine[other

causes excluded]• Intolerance to ACE-Is,ARBs[>30%

increase in creatinine,severe hyperkalemia]• Recurrent pulmonary edema,CHF

PTRA

• Proved successful in fibro muscular dysplasia and ASRVD• Success rate75%-80%• PTRA alone high early restenosis rate

upto 30%at 6-12 months• Low success rate with ostial

disease,diffuse&large lesion, totally occluded vessel

Renal complications of PTRA

• Haematoma• Haemorrhage• Pseudoaneuysm or dissection of access

vessel• Dissection & rupture of renal artery• Renal artery thrombosis• Acute renal failure• Distal cholestrol embolism

ENDOVASCULAR STENTS

• Preferred renal artery revascularization in most the centers• Higher risk for renal.A

dissection,rupture and thrombosis• Most of the restenosis occur in first

6months of intervention,common in smaller vesels

Indicators of restenosis

• Worsening of blood pressure• Worsening of renal function• Silent renal atrophy

Surgical revascularisation

• Replaced by endovascular stents• Excellent long term patency rate-93%• Predictors of good outcome Lower preoperative S.creatinine-2mg Bilateral renovascular disease Recent rapid decline of renal function

• Aortorenal bypass: autogenous or synthetic graft Extra-anatomic bypass: splenorenal hepatorenal ileorenal Supradiaphragmatic,supraceliac and thoracic

aortorenal bypass Transaortic renal endarterectomy

Transplant renal artery stenosis

• Transplant RA stenosis Commonly occurs period between 3months to 2years after transplantation• Use of pediatric kidney to adult recipients high

risk for stenosis• Pseudotransplant RA stenosis- vascular

disease proximal to allograft artery

Causes

• Commonly associated with end to end anastomoses• CMV infection• Calcineurin inhibitor toxicity• Chronic rejection

• Systolic bruits over transplant is not diagnostic• RDS is screening test of choice• PTRA or surgical revasularisation

HypertensionSus of RVH

Medical Rx ,Follow-upLow suspicious High suspicious

Medical Rx ,Follow-up Good BP control?Stable Renal Func ?

yesNo

Candidate for revascularizationRenal Func unstable or at risk

Non invasive study

Angiography

Surgical revasPTRA with Stent

Medical Rx ,Follow-up

yes

positive

No

negative

Positive high grade lesion

• Subclavian.A-93%• Common carotid.A-58%• Abdominal aorta-47%• Renal.A-38%• Aortic arch and it’s roots-35%• Vertibral.A-35%

• Panarteritis: intimal proliferation,medial fibrosis and scarring,degeneration of elasticlamina• Polymyalgiarheumatica absente• RVH occur32%to 93%

Pathophysiology

• Activation of RAS• Intrarenal activation of sympathetic

nervous system• Impairment of NO generation• Release of endothelin• Hypertensive microvascular injury to

nonstenosed kidney

Renal toxicity with ACE-Is

• Predisposing condtions• 1.Bilateral RA stenosis• 2.Solitary functioning kidney• 3.Widespread atherosclerosis• 4.Impaired pretreatment

renalfunction

• 5. Diuretic therapy• 6.Volume losses: vomiting,diarrhea• 7.NSAIDs• 8.Low sodium intake