Treatment of severe renal artery stenosis by percutaneous transluminal renal angioplasty and stent implantation: review of the pediatric experience: apropos of two cases

Pediatric Renovascular Hypertension: A Pediatric Interventional Radiologist's Perspective

Renovascular hypertension (RVH) contributes close to one-fourth of the secondary etiologies of hypertension in children and a delay in diagnosis can result in adverse clinical outcomes. RVH in children is clinically silent with elevations in blood pressure measurements sometimes as its sole manifestation. Only a high index of suspicion by the clinician can prompt its detection. Despite the availability of other imaging modalities like ultrasound, computed tomography, and magnetic resonance imaging, digital subtraction angiography is still considered the gold standard to make a diagnosis of RVH. Angioplasty is considered the treatment of choice in appropriately selected patients. In this article, we shall focus on the various imaging findings, and management of RVH in children, which requires a multidisciplinary approach with a special focus on the role of interventional radiology.

Role of drug-eluting stent on Takayasu arteritis with renal artery stenosis

Takayasu arteritis (TA) is defined as granulomatous inflammation of large arteries involving the aorta and its primary branches. Takayasu arteritis with renal artery stenosis (TARAS) is a common cause of pediatric renovascular hypertension. The main purposes of TARAS management are to improve high blood pressure and recover renal function. When general medication fails to improve symptoms, renal revascularization may be attempted.  Implantation of a drug-eluting stent (DES) has been used as an alternative strategy for pediatric renal revascularization. Here, we report on a 10-year-old, female, Javanese patient with bilateral TARAS who underwent DES implantation. Her clinical presentation was hypertensive crisis and worsened renal function. Bilateral renal artery DES implantation was performed successfully without complications. The child’s blood pressure was controlled using two anti-hypertensive medications after DES implantation and her renal function recovered. Dual anti-platelet therapy was given to minimize the risk of stent thrombosis.

Mid-term outcome of angioplasty for pediatric renovascular hypertension

PURPOSE

To evaluate the mid-term outcome of percutaneous transluminal renal angioplasty (PTRA) for pediatric renovascular hypertension (RVH).

MATERIALS AND METHODS

The clinical data of patients who underwent PTRA for RVH in our hospital from 2012 to 2019 were analyzed retrospectively. Post-procedural blood pressure, glomerular filtration rate (GFR) of the affected kidney, restenosis and complications were closely followed up.

RESULTS

The procedure of PTRA was performed in total of 30 children (20 males and 10 females), with a mean age of 7.32±0.74 years (40 days ∼13.92 years) and a mean weight of 24.99±2.26 kg (3.4 ∼ 53kg). The median follow-up period was 26.5 months (1 month ∼7.5 years). Technical success was achieved in 26 of 30 patients (86.7%). Three patients (10.0%) developed restenosis. Only 1 patient underwent stent implantation, and the stent fractured 8 months later, requiring further intervention. No other complication was found. In terms of clinical benefit of blood pressure control after the initial PTRA procedure, 15 patients (50%) were cured and 7 (23.3%) improved. There was no significant difference in etiology, lesion location and length between patients with clinical benefit and failure (p=0.06, 0.202 and 0.06). The GFR of the affected kidney was significantly improved from 19.85±11.24 (ml/min) to 38.09±11.88 (ml/min) at 6 months follow-up after PTRA (p<0.001).

CONCLUSION

The overall results of PTRA for pediatric RVH caused by different etiologies are promising. Not only does it provide clinical benefit of blood pressure control in 73.3% of patients, it also significantly improves the function of the affected kidney.

Renovascular hypertension in children

Paediatric hypertension, defined as systolic blood pressure > 95th percentile for age, sex and height is often incidentally diagnosed. Renovascular hypertension (RVH) is responsible for 5-25% of hypertension in children. Renal artery stenosis and middle aortic syndrome can both can be associated with various conditions such as fibromuscular dysplasia, Williams syndrome & Neurofibromatosis type 1. This paper discusses the approaches to diagnosis and interventional management and outcomes of renovascular hypertension in children. Angiography is considered the gold standard in establishing the diagnosis of renovascular disease in children. Angioplasty is beneficial in the majority of patients and generally repeated angioplasty is considered more appropriate than stenting. Surgical options should first be considered before placing a stent unless there is an emergent requirement. Given the established safety and success of endovascular intervention, at most institutions it remains the preferred treatment option.

Complex Vascular Revascularization in a Young Woman with Type 1 Neurofibromatosis

We present an uncommon case of a 16-year-old woman with type 1 neurofibromatosis and renovascular hypertension due to bilateral renal stenosis associated with asymptomatic digestive artery stenosis. Our patient was treated by several autologous bypasses to the superior mesenteric artery and the left and right renal arteries. She had no postoperative complications and good clinical and imaging outcomes at 10 years. Furthermore, there are few data on the vascular impairment of this rare disease, thus justifying its presentation.

Efficacy of Antihypertensive Therapy in a Child with Unilateral Focal Fibromuscular Dysplasia of the Renal Artery: A Case Study and Review of Literature

Background: Fibromuscular dysplasia (FMD) is one of the important etiologies of renovascular hypertension in children. It is usually resistant to multiple antihypertensive agents and can cause extreme elevation in blood pressures, which can lead to end organ damage if not promptly diagnosed and treated. Treatment options include medical management with antihypertensive agents, balloon or stent angioplasties, surgical revascularization, and nephrectomy. The aim of the study was to review the efficacy of antihypertensive therapy only in the management of FMD in a very young child. Methods: This is a retrospective chart study with review of literature. Results: Here, we report a 22-month-old toddler who presented with severe resistant hypertension and cardiomyopathy who was found to have focal FMD of the right renal artery. She also presented with proteinuria, hyponatremia that was probably secondary to pressure natriuresis, hypokalemia, hyperaldosteronism, and elevated plasma renin activity. The stabilization of blood pressures was done medically with the usage of antihypertensive medications only, without the need for angioplasty or surgical revascularization. Conclusions: We demonstrate that surgical intervention may not always be necessary in the treatment of all cases of FMD, especially in a small child where such intervention may be technically challenging and lead to potential complications. Hence, medical management alone may be sufficient, at least for the short-term, in small children with controlled hypertension and normal renal function, with surgical intervention reserved for FMD with medication-refractory hypertension and/or compromised renal function.

Endovascular Management of Neurofibromatosis Type I-Associated Vasculopathy: A Case Series and Brief Review of the Literature

Purpose:

Neurofibromatosis type 1 (NF1) is an autosomal-dominant disorder found in approximately 1 of every 3000 individuals. Neurofibromatosis type 1 can have vascular manifestations including aneurysms, stenoses, and arteriovenous malformations. The purpose of this article is to describe the clinical manifestations of NF1 vasculopathy, discuss therapeutic options, and highlight endovascular therapies from our institutional experience.

Materials and Methods:

The radiology information system was searched for cases of NF1. Cases with vasculopathy managed with endovascular therapies were included. Demographics, clinical histories, procedural details, and outcomes were recorded. A review of the literature for the management strategies of NF1 vasculopathy was performed.

Results:

Two pediatric patients with NF1 were identified, both of whom presented with hypertension found to be secondary to renal artery stenosis. One of the patients also had infrarenal aortic narrowing. Both patients were successfully treated with balloon angioplasty, resulting in improved blood pressures. The review of the literature identified case series of pharmacologic, surgical, and endovascular therapies, although, endovascular therapies appear to be preferred due to lower morbidity and mortality.

Conclusions:

NF1 vasculopathy is a rare condition that most often presents with hypertension due to renal artery stenosis. In these situations, endovascular management is the preferred approach.

Treatment of Renal Artery Stenosis in a Solitary Kidney Using Cutting Balloon Angioplasty in a Paediatric Patient

Aims:

Renovascular hypertension is a rare cause of paediatric hypertension. It is however, a potentially treatable cause particularly when caused by renal artery stenosis (RAS).

Materials and Methods:

We present the case of an 11-month-old girl presenting with cardiac dysfunction. She was found to be hypertensive with a systolic blood pressure >180mmHg. DMSA demonstrated a small right kidney and a divided renal function of 6% on the right and 94% on the left. Spectral analysis demonstrated abnormal waveforms suggestive of RAS of the left kidney.

Results:

Angioplasty with a cutting balloon was successful. Blood pressure measurements, renal function and left ventricular function improved.

Conclusion:

RAS can be successfully treated with cutting balloon angioplasty after failure of convention balloon angioplasty to relieve the narrowing. In our case, there was an immediate successful angiographic result that on mid-term follow-up demonstrated significant improvement in clinical and biochemical outcomes and cessation of all anti-hypertensive medication.

The management of pediatric renovascular hypertension: a single center experience and review of the literature

INTRODUCTION

Renal artery occlusive disease is poorly characterized in children; treatments include medications, endovascular techniques, and surgery. We aimed to describe the course of renovascular hypertension (RVH), its treatments and outcomes.

METHODS

We performed literature review and retrospective review (1993-2014) of children with renovascular hypertension at our institution. Response to treatment was defined by National High Blood Pressure Education Program Working Group on High Blood Pressure in Children and Adolescents at most-recent follow-up.

RESULTS

We identified 39 patients with RVH. 54% (n=21) were male, with mean age of 6.93 ± 5.27 years. Most underwent endovascular treatment (n=17), with medication alone (n=12) and surgery (n=10) less commonly utilized. Endovascular treatment resulted in 18% cure, 65% improvement and 18% failure; surgery resulted in 30% cure, 50% improvement and 20% failure. Medication alone resulted in 0% cure, 75% improvement and 25% failure. 24% with endovascular treatment required secondary endovascular intervention; 18% required secondary surgery. 20% of patients who underwent initial surgery required reoperation for re-stenosis. Mean follow-up was 52.2 ± 58.4 months.

CONCLUSIONS

RVH treatment in children includes medications, surgical or endovascular approaches, with all resulting in combined 79% improvement in or cure rates. A multidisciplinary approach and individualized patient management are critical to optimize outcomes.

TYPE OF STUDY

Retrospective comparative study LEVEL OF EVIDENCE: Level III.

Application of Duplex Ultrasonography in the Midaortic Syndrome

Objective

Midaortic syndrome is a rare condition found primarily in children that causes stenosis of the abdominal aorta and its proximal branches. Duplex interpretation criteria derived from adults do not necessarily apply to the pediatric population but are sometimes used empirically in specific cases. We report the case of a 5-year-old girl whose aorta and renal arteries were studied by duplex ultrasound, with anatomic and radiologic correlation.

Case Report

The patient was a 5-year-old girl with refractory hypertension on multiple antihypertensive medications. Her initial diagnosis of midaortic syndrome was made via duplex ultrasound. The findings were confirmed by angiography and showed smooth narrowing of the mid- to distal abdominal aorta with concomitant bilateral renal artery origin stenosis. Surgical repair of the aorta was performed with the use of a patch angioplasty technique with pulmonary artery homograft. The left renal artery was re-implanted onto the infrarenal aorta and an aorta to right renal artery bypass graft was placed using autogenous left internal iliac artery. Duplex ultrasound was then used to evaluate the success of the surgical repair.

Conclusion

Duplex ultrasound proved effective in the preoperative and postoperative care of this small child with midaortic syndrome and renal artery stenosis. The standard adult criteria for renal artery stenosis can be used selectively in children to assist in the diagnosis of unusual vascular conditions.

Treatment of a recurrent renal artery stenosis and stent fracture using a drug eluting stent in a pediatric patient

Renal artery obstruction is uncommon in the pediatric population and therefore represents a challenging diagnosis to ascertain and treat. While angioplasty and surgery have been used to treat it, stent implantation has been left mainly for adult use. In the following paper, we expose the case of an 8-year-old female who presented with severe arterial hypertension. Initially, the patient was evaluated and up to 5 antihypertensive medications were started. After complete evaluation, she was found to have severe right renal artery distal and proximal stenosis. She underwent recurrent angioplasties and then a bare metal stent (BMS) implantation, due to recurrence of stenosis. The original BMS developed a circumferential fracture, leading to a second stent implant, this time using a drug eluting stent (DES). She has been stable for 8 years since the last intervention, although using 2 antihypertensive medications. The use of BMS and DES may add another tool in the armamentarium of the pediatric interventionist to treat these children with recurrent stenosis that fail angioplasty.

Remedial operations for failed endovascular therapy of 32 renal artery stenoses in 24 children

BACKGROUND

Percutaneous transluminal angioplasty (PTA) for the treatment of pediatric renovascular hypertension (RVH) in contemporary practice is accompanied with ill-defined complications. This study examines the mode of pediatric renal PTA failures and the results of their surgical management.

METHODS

Twenty-four children underwent remedial operations at the University of Michigan from 1996 to 2014 for failures of renal PTA. Their clinical courses were retrospectively reviewed and results analyzed.

RESULTS

Renal PTA of 32 arteries, including 13 with stenting, was performed for severe RVH in 12 boys and 12 girls, having a mean age of 9.3 years. Developmental ostial stenoses affected 22 children. PTA failures included: 27 restenoses and five thromboses. Remedial operations included: 13 renal artery-aortic reimplantations, one segmental renal artery-main renal artery reimplantation, ten aortorenal bypasses, one arterioplasty, one iliorenal bypass, and six nephrectomies for unreconstructable arteries; the latter all in children younger than 10 years. Follow-up averaged 2.1 years. Postoperatively, hypertension was cured, improved, or unchanged in 25, 54, and 21 %, respectively. There was no perioperative renal failure or mortality.

CONCLUSIONS

Renal PTA for the treatment of pediatric RVH due to ostial disease may be complicated by failures requiring complex remedial operations or nephrectomy, the latter usually affecting younger children.

Middle aortic syndrome--an 8-year story of pills, pretty balloons and struts

BACKGROUND

Middle aortic syndrome (MAS) is an uncommon cause of hypertension in children. The management of hypertension secondary to MAS frequently requires several anti-hypertensive medications along with endovascular and often surgical intervention.

CASE-DIAGNOSIS/TREATMENT

A 9-year-old boy presented with headaches and vomiting and was diagnosed with severe hypertension secondary to idiopathic MAS affecting a long segment of the abdominal aorta and left renal artery stenosis. Over the following 8 years his hypertension was successfully managed initially with percutaneous transluminal balloon angioplasty (PTA) of his left renal artery, followed by balloon dilatation of his abdominal aortic narrowing. He subsequently underwent abdominal aortic stent placement following failed repeat aortic balloon dilatation. Aged 17 years and 6 months he is now on a single anti-hypertensive agent with normal renal function and no evidence of target organ damage.

CONCLUSION

In selected cases, MAS may be managed with PTA and stent placement with good long-term outcomes. Limited data on the use of PTA and stent insertion in children means that a structured approach to the management of refractory hypertension secondary to MAS remains elusive.

Angioplasty for pediatric renovascular hypertension: a 13-year experience

PURPOSE

We aimed to evaluate the long-term outcome and efficacy of percutaneous transluminal renal angioplasty (PTRA) for pediatric renal artery stenosis (RAS), which is an important cause of medication-refractory pediatric hypertension.

MATERIALS AND METHODS

We retrospectively evaluated 22 hypertensive children (age range, 3-17 years) who underwent PTRA from February 2000 to July 2012. Sixteen patients had Takayasu arteritis and six fibromuscular dysplasia. Five were not included in the statistical analysis due to loss to follow-up.

RESULTS

Technical success was achieved in 32 of 34 procedures (94.1%). The stenosis rate decreased from 84.5% before PTRA to 20.1% after PTRA. Treatment was effective in 72.7% (16/22) of patients, including complete cure in 27.3% (6/22) and improvement in 45.5% (10/22). Systolic and diastolic blood pressures decreased from 153 ± 19.1 to 131.7 ± 21.4 mmHg and from 97.9 ± 14.2 to 83.6 ± 19.3 mmHg, respectively (P <0.01). Number of antihypertensive agents decreased from 2.7 to 0.5 per patient. Restenosis was detected in 40.9% (9/22) of patients, with a restenotic interval of 11.8 months (range, 3-47 months). Lesion length was strongly correlated with clinical success (cure and improvement) (independent-sample t test, P <0.001; binary logistic regression, P = 0.040).

CONCLUSION

Lesion length is an important determination of clinical success with PTRA for pediatric RAS. PTRA is an appropriate treatment option for pediatric renovascular hypertension due to Takayasu arteritis and fibromuscular dysplasia.

Disease Beyond the Arch: A Systematic Review of Middle Aortic Syndrome in Childhood

BACKGROUND

Middle aortic syndrome (MAS) is a rare clinical entity in childhood, characterized by a severe narrowing of the distal thoracic and/or abdominal aorta, and associated with significant morbidity and mortality. MAS remains a relatively poorly defined disease. This paper systematically reviews the current knowledge on MAS with respect to etiology, clinical impact, and therapeutic options.

METHODS

A systematic search of 3 databases (Embase, MEDLINE, and Cochrane Central Register of Controlled Trials) yielded 1,252 abstracts that were screened based on eligibility criteria resulting in 184 full-text articles with 630 reported cases of childhood MAS. Data extracted included patient characteristics, clinical presentation, vascular phenotype, management, and outcomes.

RESULTS

Most cases of MAS are idiopathic (64%), 15% are associated with Mendelian disorders, and 17% are related to inflammatory diseases. Extra-aortic involvement including renal (70%), superior mesenteric (30%), and celiac (22%) arteries is common, especially among those with associated Mendelian disorders. Inferior mesenteric artery involvement is almost never reported. The majority of cases (72%) undergo endovascular or surgical management with residual hypertension reported in 34% of cases, requiring medication or reintervention. Clinical manifestations and extent of extra-aortic involvement are lacking.

CONCLUSIONS

MAS presents with significant involvement of visceral arteries with over two thirds of cases having renal artery stenosis, and one third with superior mesenteric artery stenosis. The extent of disease is worse among those with genetic and inflammatory conditions. Further studies are needed to better understand etiology, long-term effectiveness of treatment, and to determine the optimal management of this potentially devastating condition.

Angioplasty for renovascular hypertension in 78 children

OBJECTIVES

To evaluate the outcome of percutaneous transluminal angioplasty (PTA) in children with renovascular hypertension (RVH) treated at a single centre over 29 years.

METHODS

A retrospective study of the medical charts of all children with RVH who underwent PTA between 1984 and 2012. The primary outcome measurement was blood pressure (BP) achieved after the procedure. The BP before the procedure was compared with that at last available follow-up, 6 (range 0.6-16) years after the initial procedure.

RESULTS

Seventy-eight children with median (range) age of 6.5 (0.5-17) years were studied. Twenty-three (29.5%) had an underlying syndrome, 35 (44.9%) children had bilateral renal artery stenosis (RAS), 18 (23%) intrarenal disease and 11(14%) showed bilateral RAS and intrarenal disease. Twenty (25.6%) children had mid-aortic syndrome and 14 (17.9%) cerebrovascular disease. One hundred and fourteen PTA procedures were carried out including 31 stent insertions. Following PTA, BP was improved in 49 (62.8%) children and of those 18 (23.1%) were cured. Children with involvement of only the main renal arteries showed improved BP control in 79.9% of the children with cure in 39.5%. BP was intentionally maintained above the 95th centile for age and height in four children with coexistent cerebrovascular disease. No change in BP was seen in 18 children despite observed technical success of the PTA, and in seven children due to technical failure of the procedure.

CONCLUSIONS

PTA provided a clinical benefit in 62.8% of children with RVH.

Atherosclerotic renal artery stenosis as a cause for hypertension in an adolescent patient

BACKGROUND

Atherosclerosis causing renal artery stenosis (RAS) is one of the most common secondary causes of hypertension in adults, but is rare in children.

CASE-DIAGNOSIS/TREATMENT

RAS associated with coronary artery stenosis was diagnosed in a teenage patient who presented with intermittent chest pain and elevated blood pressures for 6 years. The diagnosis of RAS was suspected after physical examination revealed an abdominal bruit. Renal ultrasound with Doppler revealed normal appearing kidneys with high velocity in the aorta and renal arteries. Computed tomography angiography (CTA) of the chest and abdomen demonstrated generalized calcified atherosclerotic narrowing of the arteries including the renal, celiac, superior mesenteric and coronary arteries in the setting of hyperlipidemia. The lipid panel revealed hypercholesterolemia with elevated serum plant sterol concentrations, suggesting the diagnosis of sitosterolemia. Cardiac catheterization demonstrated left anterior descending artery and left circumflex artery stenosis, which required bypass of the left anterior descending artery and stenting of the left circumflex artery. Aggressive lipid control was recommended and he was treated medically with a beta-blocker, low-dose angiotensin-converting enzyme inhibitor, aspirin, statin, and clopidogrel.

CONCLUSION

Although very rare, generalized atherosclerosis caused by genetic disorders should be considered an underlying cause for severe hypertension in children with hyperlipidemia.

Renal artery stenosis in children: therapeutic percutaneous balloon and stent angioplasty

BACKGROUND

Renal artery stenosis (RAS) accounts for 10 % of cases of systemic hypertension in children. Initial management involves anti-hypertensive therapy. Percutaneous interventions are documented for the treatment of RAS in the adult population. In children, case reports suggest benefit.

METHODS

This is a retrospective analysis of consecutive patients referred for catheterization for RAS between 2002 and 2010 at a single institution. Recorded variables included: age, weight, systemic blood pressure, minimal luminal diameter, interventional devices, antihypertensive medications, contrast volume, and complications.

RESULTS

Twelve patients (median age 8.2, IQR 6-12.4 years); median weight 42.8 kg, IQR: 25-47.4 kg) were referred for renal artery catheterization and underwent percutaneous intervention. Overall, minimal luminal diameter (MLD) increased by 1.2 ± 0.9 mm for all patients (p < 0.05) and by 1.3 ± 0.9 mm for post-renal transplant patients (p < 0.05). Only stent angioplasty patients demonstrated significant improved blood pressure (p < 0.05). One patient had stent thrombosis requiring re-intervention with repeat balloon angioplasty.

CONCLUSIONS

This retrospective analysis suggests that percutaneous intervention might play a role in the management of RAS, with an improvement in MLD in children with RAS. Transcatheter intervention is technically feasible with low morbidity. A prospective, longitudinal study is warranted to compare standard medical therapy with percutaneous interventions.

Renal artery stenosis due to neurofibromatosis type 1: case report and literature review

Background

Neurofibromatosis type 1 (NF1) is a relatively common autosomal dominant disorder. The most common vascular abnormality in patients with NF1 is bilateral or unilateral renal artery stenosis.

Case report

A 16-year-old boy presented with a headache of 4-year duration and was found to be moderately hypertensive. On physical examination, axillary freckling and multiple café-au-lait spots were revealed over the trunk, while numerous small nodules were palpable on the limbs. Biopsy of subcutaneous nodule showed neurofibroma. Lisch nodules were identified on slit-lamp examination and grade I hypertensive retinopathy was present on fundoscopy. Clinical laboratory investigations revealed that renal and liver function tests, blood cells count, urinalysis, serum electrolytes, serum levels of renin and aldosterone, and 24-hour urine levels of catecholamines were all within normal ranges. Abdominal ultrasound and CT were normal. Both kidneys were of normal size. CT angiography showed right renal artery stenosis (>90%) at the ostium. The final diagnosis of NF1 with right renal artery stenosis and secondary hypertension was then made. The patient was treated with Procardin (30 mg/d) and improved with a significant decline in blood pressure. The main outcomes were to control blood pressure without necessarily proceeding with PTRA. We also present a review of the literature.

Conclusions

NF1 may present with hypertension due to renal artery stenosis in children. All young patients (<30 year) with hypertension should be clinically screened for secondary causes of hypertension, including NF1, so that renal revascularization can be offered before permanent end organ damage has occurred. First-line management using medication alone could be appropriate, keeping the interventional options for when the patient's condition deteriorates.

Posterior reversible encephalopathy syndrome revealing renal artery stenosis in a child

A 14-year-old girl was admitted to the emergency department for repeated seizures with no fever. High blood pressure at admission was ascribed to the status epilepticus. Seizure recurrence promoted transfer to the paediatric intensive care unit. The MRI visualised bilateral, subcortical, white-matter lesions in the parietal and occipital lobes suggesting posterior reversible encephalopathy syndrome (PRES). Continuous nicardipine infusion corrected the hypertension and neurological manifestations within a few hours. The diagnostic workup showed right renal artery stenosis. Blood pressure returned to normal values for age after right nephrectomy. She was discharged home without treatment. She had no residual neurological impairments. This case highlights the risk of misinterpreting sustained hypertension in children with repeated seizures. We briefly review paediatric PRES, which is rare as compared to adults. Increased awareness among critical care physicians, together with greater availability of cerebral MRI, is decreasing the time to diagnosis.

Idiopathic midaortic syndrome: normalization of blood pressure on medication

Midaortic syndrome (MAS) is a rare, idiopathic condition in children usually presenting with severe hypertension. We report a case of a 13-year-old girl who presented with severe hypertension (200/110 mmHg) associated with renal artery stenosis and normal renal function (creatinine clearance 110 ml/min/1.73m(2)). Percutaneous angioplasty (PTA) was first performed, but early recurrence of hypertension occurred. Subsequent imaging evaluation demonstrated association of aortic narrowing, proximal stenosis of the left renal artery, and wall thickening of superior mesenteric artery and right common carotid artery. Although previous large-vessel arteritis cannot be absolutely excluded, a diagnosis of idiopathic MAS was made, given the absence of any other clinical signs of inflammation (C-reactive protein <0.5 mg/dl; erythrocyte sedimentation rate 5 mm/h). Medical treatment was undertaken without repeat PTA or surgery. Blood pressure control was good, and antihypertensive therapy was stopped 4 years later. At age 22, the patient was still normotensive and receiving no antihypertensive therapy; normalization of Doppler velocities in the proximal left renal artery was confirmed. In the absence of renal dysfunction or target-organ damage, medical management of hypertension in MAS is feasible without intervention if blood pressure is well controlled on two antihypertensive agents.

Malignant hypertension secondary to renovascular disease during infancy--an unusual cause of failure to thrive

An 11-month-old girl presented with a history of failure to thrive, vomiting, polydipsia, polyuria and visual inattention. She was found to have malignant hypertension due to unilateral renal artery stenosis. This was successfully treated with percutaneous transluminal balloon angioplasty. Nearly 10 years following this initial presentation, she remains normotensive on no anti-hypertensive medications.

Renal manifestations in toddlers with Takayasu's arteritis and malignant hypertension

Three children under the age of 3 years presented with malignant hypertension, proteinuria, and acute kidney injury. Takayasu's arteritis was diagnosed on the basis of clinical symptoms of weight loss and low grade fever in conjunction with elevated sedimentation rate and radiographic evidence of aortic and renal artery stenosis. One patient had a renal biopsy which showed arteriolar sclerosis and focal glomerulosclerosis. All three patients required multiple antihypertensive agents, ultimately including angiotensin receptor blockers and/or angiotensin converting enzyme inhibitors. The vasculitis was treated with pulse corticosteroids followed by cyclophosphamide in one patient and mycophenolate mofetil as maintenance therapy in all. Follow-up has ranged from 2 to 8 years. Although global renal function has normalized in each patient, two have unilateral non-function of one kidney. The last patient has persistent aortic and renal artery stenosis with complex collateralization requiring ongoing medical and anticipated surgical management.

Extra-anatomic bypass for recurrent abdominal aortic and renal in-stent stenoses following radiotherapy for neuroblastoma

We describe the case of an 11-year-old girl with an abdominal neuroblastoma which was operated and intraoperatively irradiated nine years ago. After six years, she developed stenoses of the infrarenal abdominal aorta and both renal arteries. Initial treatment of the stenosed vessels comprised endovascular balloon dilatations and repeated stent-graft implantations, including drug eluting stents. However, severe in-stent stenoses occurred during follow-up and the girl developed acute renal failure. Open surgery was performed with two extra-anatomic bypasses, a thoracic-to-abdominal aortic bypass and a left iliac-to-renal bypass, on an urgent basis. The postoperative course was uneventful and the patient was discharged home two weeks after the operation with full recovery of renal function. We conclude that endovascular stent-graft placement in children can only be a palliative treatment due to outgrowing of the stent-graft and the potential risk of re-stenosis, especially after a history of irradiation. Vascular surgery with placement of extra-anatomic bypasses will provide a definite treatment.

Renovascular hypertension in children

Renovascular disease is an uncommon but important cause of hypertension in children. It is usually diagnosed after a long delay because blood pressure is infrequently measured in children and high values are generally dismissed as inaccurate. Many children with renovascular disease have abnormalities of other blood vessels (aorta, cerebral, intestinal, or iliac). Individuals suspected of having the disorder can be investigated further with CT, MRI, or renal scintigraphy done before and after administration of an angiotensin-converting-enzyme inhibitor, but angiography is still the gold standard. Most children with renovascular disease will need interventional or surgical treatment. Endovascular treatment with or without stenting will cure or reduce high blood pressure in more than half of all affected children. Surgical intervention, if needed, should be delayed preferably until an age when the child is fully grown. Modern treatment provided by a multidisciplinary team of paediatric nephrologists, interventional radiologists, and vascular surgeons offers good long-term treatment results.

Mid-aortic syndrome: A case report and review of the literature

Renovascular disease is an important cause of secondary hypertension in children. In contrary to the adult patients whose major cause of renal artery stenosis (RAS) is atherosclerosis, fibromuscular dysplasia is responsible for the renovascular hypertension in most children. Mid-aortic syndrome (MAS) is a rare abnormality referring to an isolated disease of the distal thoracic and abdominal aorta resulting in significant tubular narrowing with stenosis of the visceral and renal arteries. It is usually diagnosed in young adults, but may present in childhood as a challenging problem. Patients with MAS are often first detected due to refractory hypertension. Other later presentations include intermittent claudication, congestive heart failure, renal insufficiency and symptoms of hypertensive associated end-organ damage. We report a case of a 16-year-old patient with MAS who suffered from malignant arterial hypertension. A percutaneous transluminal renal angioplasty (PTRA) was first performed, however the stenosis proved resistant to dilatation and only resulted in a minimal angiographic improvement. Due to persistent hypertension, an aortorenal bypass using the saphenous vein was performed. We also reviewed the literature on PTRA and the surgical management of RAS in MAS patients, in which PTRA often carries poor results.

Renal Artery Intervention in Pediatric and Adolescent Patients: A 20-Year Experience

Between 1986 and 2005, 22 patients (mean age, 14.7 years; range, 3-21) with renal hypertension underwent renal artery revascularization for 28 lesions, 23 with open repair (OR) and 5 with percutaneous transluminal renal angioplasty (PTRA). Thirty-day morbidity was 17% (4/23). Hypertension was cured in 13 (57%), improved in 8 (38%), and unchanged in 1 (5%). Renal function worsened in 1. At a mean follow-up of 4.9 years, 1-year patency rate was 94% and maintained for 5 years. Hypertension at 1 year was cured in 6 of 14 patients (43%; OR, 4; PTRA, 2) and improved in 8 (57%; OR, 7; PTRA, 1); hypertension at 5 years was cured in 50% and improved in 50%. Renal function remained unchanged in all patients who were followed. The authors conclude that both OR and PTRA benefit pediatric patients. PTRA for selected patients may be promising as a first line treatment or as a bridge to definitive OR in children with small arteries.

Reno-vascular hypertension in childhood: a nationwide survey

Renovascular disease accounts for 8-10% of all cases of paediatric hypertension, whereas, in adults, its incidence is approximately 1%. The Turkish Paediatric Hypertension Group aimed to create the first registry database for childhood renovascular hypertension in Turkey. Twenty of the 28 paediatric nephrology centres in Turkey responded to the survey and reported 45 patients (27 girls, 18 boys) with renovascular hypertension between 1990 and 2005. The age at presentation ranged from 20 days to 17 years. The mean blood pressure at the diagnosis was 169/110 mmHg. Chief complaints of symptomatic patients were headache (38%), seizure (18%), epistaxis (4%), growth retardation (4%), cognitive dysfunction (4%), polyuria (2%), palpitation (2%), and hemiplegia (2%). Renovascular hypertension was found incidentally in 11 children. The diagnosis of renovascular hypertension was established with conventional angiography in 39 patients, MR angiography in three, CT angiography in two, and captopril diethylene triamine penta-acetic acid (DTPA) scintigraphy in one patient. Twenty-one children had bilateral renal artery stenosis and 24 had unilateral renal artery stenosis. Of these, 14 (31%) had fibromuscular dysplasia; 12 (27%) Takayasu's arteritis; six (13%) neurofibromatosis; two (5%) Williams syndrome; one (2%) Kawasaki disease; one (2%) mid-aortic syndrome; one (2%) extrinsic compression to the renal artery, and eight (18%) unspecified bilateral renal artery stenosis. Hypertension was controlled with antihypertensive drugs in 17 patients. Percutaneous transluminal angioplasty (PTRA) or surgery had to be performed in 28 patients: PTRA in 16 patients, PTRA + surgery in one patient and surgery in 11 patients (four nephrectomies). The importance of vasculitic disease, especially Takayasu's arteritis, should not be underestimated in children with renovascular hypertension.