renal artery stenosis: an important cause of hypertension dr claire hathorn spr, rhsc edinburgh 11...

Renal Artery Stenosis: An important cause of hypertension

Dr Claire HathornSpR, RHSC Edinburgh

11th May 2010

Presentation

• 3 year old girl

• Well• Minor intercurrent illness – A&E• BP 144/91

History & Examination

• Asymptomatic

• PMH – Eczema, viral induced wheeze• FH – nil of note

• Normal examination• Height and weight on 97th centile

Initial Investigations

• BP 120-140 / 90-100 mmHg

• Urinalysis negative• FBC, U&Es, LFTs, coagulation • 4 limb BP • ECG• Renal USS & dopplers

• ALL NORMAL

Further Investigations

• Renin 2.6• Aldosterone 136• Cortisol 192• PTH 34• ACTH 12• Complement 560• C3 1.01• C4 0.18• ANA neg

• Urine catecholamines N• Urine cortisol

11.9• Urine prot:creat ratio 39

(slightly raised)• Urine MC&S negative

Radiology

• Echo – normal

• DMSA – divided function 50%

• MR Angiogram – slight irregularity of superior surface of right renal artery, felt unlikely to represent stenosis. No evidence of duplex. Conclusion: normal.

DMSA

MR Angiogram

Specialist Opinions

• Cardiology:– No clinical evidence of coarctation– No LVH on Echo

• Ophthalmology – Examination normal– No hypertensive retinopathy

• No cause or complication of hypertension

Impression & Management

• Blood pressure not well-controlled on 3 drugs– Atenolol 20mg bd – Amlodipine 2.5mg od– Doxazosin 0.5mg od

• Renovascular disease most likely diagnosis

• Referred for formal angiography at Great Ormond Street Hospital

Angiography

• Critical stenosis of left upper pole branch of main renal artery

• Normal right renal arteries

• Angioplasty performed

• Atenolol & Doxazosin stopped• Aspirin started

Progress

• Remained hypertensive 1 month post-angioplasty: 120/61

• Amlodipine continued• Doxazosin restarted

• 3 months post-angioplasty, BP well-controlled: 50-75th centile

Discussion

Renovascular Hypertension

• Aetiology• Clinical Features• Investigations• Management

Renovascular Hypertension

• 5-10% of all childhood hypertension

• Amenable to potentially curative treatment

• Causes & management different to adults

Aetiology in Children

• Fibromuscular dysplasia – most common in UK

• Syndromes: Neurofibromatosis, Williams, Marfan• Vasculitides: Takayasu, Kawasaki• Extrinsic compression: Wilm’s, Neuroblastoma• Other: Renal transplant, trauma, radiation

Clinical Spectrum

• Bilateral disease in 53-78%• Intrarenal disease in 44%• Intrarenal & main artery stenosis in 31%

• Most children without co-morbidities have single focal branch artery stenosis

Tullus et al. Renovascular hypertension in children. Lancet. 2008;371:1453-1463

Anatomic distribution of renal artery stenosis in children: implications for imaging

• Cinncinnati Children’s Hospital, 1993-2005• 24 stenoses identified in 21 children, R=L• 12 male, mean age 9yrs 3mths (30 mths – 18 yrs)• No co-morbidities• 90% children had a single stenosis • 75% lesions located in branch / accessory arteries

Vo et al. Pediatric Radiology 2006;36:1032

Clinical Features

Schroff et al. Angioplasty for renovascular hypertension in children: 20 year experience. Pediatrics 2006;118:268-275

Presenting Feature No. n=33

Incidental finding 9

Cardiac (CCF, palpitations, murmur) 7

Headache +/- vomiting & lethargy 6

Acute hypertensive encephalopathy 3

Cerebrovascular accident 2

Facial palsy 2

Failure to thrive 2

Screening for NF1 2

Renovascular disease and more widespread arterial involvement

Schroff et al 2006 (%)

Stadermann et al 2010

(%)Bilateral RAS 48 51

Intrarenal disease 45 -

Cerebral 21 26

Aortic 24 40

Visceral - 23

Implications of widespread arterial disease

• Improved BP control– 11/13 (85%) isolated RAS– 6/20 (30%) associated intra or extra renal disease

• Recommend routine cerebrovascular imaging– MR / PET scanning

Schroff et al. Angioplasty for renovascular hypertension in children: 20 year experience. Pediatrics 2006;118:268-275

Investigation

• Doppler ultrasound• Measurement of plasma renin activity

– Captopril plasma renin test– Renal vein sampling

• Scintigraphy: DMSA or MAG3• CT & MR angiography

• Angiography: Gold Standard

DMSA scintigraphy before & after Captopril

Tullus et al. Renovascular hypertension in children. Lancet. 2008;371:1453-1463

CT Angiogram

Tullus et al. Renovascular hypertension in children. Lancet. 2008;371:1453-1463

MR Angiogram

Angiography

• With carefully selected patients, 40% RAS

• Important therapeutic opportunity

• Visualisation of abdominal vessels

Angiography: Indications

• Tulles et al. (2008)– BP >95th centile not well-controlled on 2 drugs– Other cause not identified

• Vo et al. (2006)– Unexplained persistent HT > 95th centile

• Shahdadpuri et al. (2000)– BP > 99th centile not controlled with 1 drug– Angiography abnormal in 43% patients

A 4-year-old hypertensive boy

Vo et al. Anatomic distribution of RAS in children. Pediatric Radiology 2006;36:1032

14 yr old hypertensive girl

Vo et al. Anatomic distribution of RAS in children. Pediatric Radiology 2006;36:1032

Medical Management

• Anti-hypertensives– Multiple often required– Adequate BP control often not possible– Adverse effects common– Avoid ACE inhibitors & angiotensin receptor blockers

• Concern re renal function if BP well-controlled due to under-perfusion of kidneys

Angioplasty• 1980 : 1st successful angioplasty in a child• Balloon diameter equal to proximal artery• Stent if residual diameter stenosis <50%

• Complications– Arterial spasm– Dissection– Arterial rupture

• Post-procedure: Aspirin 3-6 monthsTullus et al. Renovascular hypertension in children. Lancet. 2008;371:1453-1463

Angioplasty for renovascular hypertension in children: 20 year experience

• Retrospective review from GOS• All children undergoing PTA 1984-2003

– Only stenoses in main or large segmental arteries– Excluded transplants & inflammatory disorders

• 33 children, 1.9-17.9 yrs (median 10.3)– 10 with underlying syndromes– 16 bilateral RAS– 15 intrarenal disease

• 48 procedures, including 15 stentsSchroff et al. Pediatrics 2006;118:268-275

Angioplasty for renovascular hypertension in children: 20 year experience

• Final outcomes of PTA:– 18 (55%) improved BP control

• 11/13 (85%) if isolated main RAS

– 10 (30%) ongoing HT despite adequate dilation– 5 (15%) PTA unsuccessful – Restenosis in 2/27 native renal arteries after balloon

dilatation, 7/19 of stented arteries– 6 (18%) suffered complications, incl 1 death

Schroff et al. Pediatrics 2006;118:268-275

Left RAS before & after Angioplasty

Schroff et al. Angioplasty for renovascular hypertension in children: 20 year experience. Pediatrics 2006;118:268-275

Surgery

• For refractory HT when medical Rx & angioplasty have failed

• Nephrectomy

• Revascularisation procedures

• Aortic reconstruction

Results of surgical treatment for RVH in children: 30 yr single centre experience

• 37 children (65% male)• 1979 - 2008• Mean SBP 140 (105-300) mmHg • 53 surgical procedures

– Nephrectomy 18– Renovascular surgery 28– Aortic reconstruction 7

Stadermann et al. Nephrology Dialysis Transplantation. 2010;25(3):807-813

Results of surgical treatment for RVH in children: 30 yr single centre experience• 12 months post-op:

– 16 (43%) normal BP without treatment– 15 (41%) normal/improved BP on 1-4 drugs– 4 (11%) unchanged

• 90% overall improvement• Complications:

– Haemorrhage (5) – Septicaemia (5)– Chylous ascites (1)

Stadermann et al. Nephrology Dialysis Transplantation. 2010;25(3):807-813

Children not amenable to Angioplasty or Surgery

• Diffuse abnormalities of very small intrarenal arteries

• Antihypertensive medication– Uncontrolled on 6-7 drugs not uncommon

• Therapeutic trial with ACE inhibitor or angiotensin blocker warranted

Tullus et al. Renovascular hypertension in children. Lancet. 2008;371:1453-1463

Suggested Investigations(Tullus 2008)

Tullus et al. Renovascular hypertension in children. Lancet. 2008;371:1453-1463

Our Patient

• 3 months post-angioplasty• BP well-controlled on 2 drugs

• Close follow-up– BP– Renal function– DMSA

• ? Consider cerebrovascular imaging

Any Questions?