Evaluation and long-term outcome of pediatric renovascular hypertension

Validation of computed tomography angiography as a complementary test in the assessment of renal artery stenosis: a comparison with digital subtraction angiography

BACKGROUND

Renal artery stenosis is an important cause of hypertension in children, accounting for 5-10% of cases. When suspected, noninvasive imaging options include ultrasound (US), computed tomography (CT) angiography and magnetic resonance (MR) angiography. However, digital subtraction angiography (DSA) remains the gold standard.

OBJECTIVE

To investigate the accuracy and inter-reader reliability of CT angiography in children with suspected renal artery stenosis.

MATERIALS AND METHODS

This is a retrospective study of patients suspected of having renal artery stenosis evaluated by both CT angiography and DSA between 2008 and 2019 at a tertiary pediatric hospital. Only children who underwent CT angiography within 6 months before DSA were included. CT angiography studies were individually reviewed by two pediatric radiologists, blinded to clinical data, other studies and each other's evaluation, to determine the presence of stenosis at the main renal artery and 2nd- and 3rd-order branches. The sensitivity, specificity and accuracy were calculated using DSA as the reference. The effective radiation dose for CT angiography and DSA was also calculated. Kappa statistics were used to assess inter-reader agreement.

RESULTS

Seventy-four renal units were evaluated (18 girls, 19 boys). The patients' median age was 8 years (range: 1-21 years). Overall, CT angiography was effective in detecting renal artery stenosis with a sensitivity of 85.7%, specificity of 91.5% and accuracy of 88.9%. There was moderate inter-reader agreement at the main renal artery level (k=0.73) and almost perfect inter-reader agreement at the 2nd/3rd order (k=0.98). However, the sensitivity at the 2nd- and 3rd-order level was lower (14.3%). CT angiography provided excellent negative predictive value for evaluating renal artery stenosis at the main renal artery level (90.1%) and at the 2nd- or 3rd-order branches (82.7%). The median effective dose of CT angiography studies was 2.2 mSv (range: 0.6-6.3) while the effective dose of DSA was 13.7 mSv.

CONCLUSION

CT angiography has high sensitivity and specificity at the main renal artery level with a lower radiation dose than previously assumed. Therefore, it can be used as a diagnostic tool in patients with low to medium risk of renal artery stenosis, and as a screening and treatment planning tool in patients at high risk.

Renovascular hypertension in pediatric patients: update on diagnosis and management

Renovascular hypertension (RVH) is defined as an elevated blood pressure caused by kidney hypoperfusion, generally as a result of anatomic stenosis of the renal artery with consequent activation of the Renin Angiotensin-Aldosterone System. The main causes include genetic and inflammatory disorders, extrinsic compression, and idiopathic alterations. RVH is often asymptomatic and should be suspected in any child with refractory hypertension, especially if other suggestive findings are present, including those with severe hypertension, abdominal bruit, and abrupt fall of glomerular filtration rate after administration of angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers. There is a consensus that digital subtraction angiography is the gold standard method for the diagnosis of RVH. Nevertheless, the role of non-invasive imaging studies such as Doppler ultrasound, magnetic resonance angiography, or computed tomographic angiography remains controversial, especially due to limited pediatric evidence. The therapeutic approach should be individualized, and management options include non-surgical pharmacological therapy and revascularization with percutaneous transluminal renal angioplasty (PTRA) or surgery. The prognosis is related to the procedure performed, and PTRA has a higher restenosis rate compared to surgery, although a decreased risk of complications. This review summarizes the causes, physiopathology, diagnosis, treatment, and prognosis of RVH in pediatric patients. Further studies are required to define the best approach for RVH in children.

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.

Does treatment-resistant hypertension exist in children? A review of the evidence

Treatment-resistant hypertension (TRH) is a well-described condition in adult patients that is associated with poor clinical outcomes. While case reports of hypertension resistant to therapy in children have been published, it is unclear if TRH truly exists in childhood. This educational review will briefly summarize recent evidence and recommendations for TRH in adults, as well as will review the literature regarding medically resistant hypertension in children and adolescents. Finally, we propose a clinical approach for evaluation hypertensive children and adolescents with apparent treatment resistance.

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.

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.

Renovascular hypertension: a case with atypical neurological signs

Secondary hypertension is the most frequent form of hypertension in children. Renovascular disease accounts for 5-10% of all childhood hypertension and should be suspected in the presence of severe hypertension found difficult to manage with medical therapy. Uncontrolled hypertension can lead to severe target organ damage. We describe the case of a 13-month-old baby boy with failure to thrive, recent muscular weakness of the lower extremities and irritability. Hypertension was detected and he was admitted to the paediatric intensive care unit with a refractory hypertensive emergency, despite multiple antihypertensive therapies. Bilateral renal artery stenosis was diagnosed through renal angiography and balloon dilation was performed, leading to lower blood pressure. He is currently withdrawing from antihypertensive medication, and slowly gaining weight and recovering from target organ damage. However, weakness of the lower extremities persists and he has been diagnosed with a neurogenic bladder.

Management of the renovascular disease in children with Takayasu arteritis

Takaysu arteritis (TA), together with fibromuscular dysplasia, is the most common cause for renovascular hypertension. The diagnosis of vasculitis is important to make as these children benefit from immunosuppressive treatment. In many cases, however, it is more difficult than commonly realised to differentiate between these two diagnoses. Imaging which allows the inflamed arterial wall to be outlined, such as magnetic resonance or positron emission tomography scans, can be very helpful in this context. Revascularisation, either with angioplasty or surgery, seems to be effective and safe, also in children with TA. Patients with inactive disease have a more successful outcome and experience fewer complications from the intervention than those with active on-going inflammation.

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.

Clinical efficacy of percutaneous transluminal renal artery stenting for the treatment of renovascular hypertension associated with Takayasu arteritis

BACKGROUND

This study aims to observe and analyze the clinical efficacy of interventional therapy for patients with Takayasu arteritis (TA) experiencing renovascular hypertension (RH).

METHODS

Eight TA patients with RH underwent percutaneous transluminal renal artery stenting (PTRAS). Patients were followed up 1, 6, 12, and 24 months postoperatively for levels of blood pressure, number of antihypertensive drugs being taken, levels of serum creatinine, and the presence of renal artery restenosis.

RESULTS

All 8 patients were successfully followed up 1, 6, and 12 months postoperatively, but 1 was lost to follow-up at 24 months. All patients had significantly lower average blood pressure levels compared with those at baseline (P < 0.05); treatment efficacy rates (recovery or improvement) at 1, 6, 12, and 24 months were 94%, 90%, 80%, and 80%, respectively. The average number of antihypertensive drugs being taken was 3.5 at baseline, 1.0 at 1 month, 0.5 at 6 months, 1.0 at 12 months, and 1.5 at 24 months. Serum creatinine levels during the follow-up period were not significantly different from those at the baseline. No patient developed renal artery restenosis during the follow-up period.

CONCLUSIONS

PTRAS is a safe and effective treatment for TA-associated RH, with a high technical success rate and a low complication rate. This interventional therapy can effectively control TA-related hypertension and can also preserve and even improve kidney function.

Optimal management of renal artery fibromuscular dysplasia

Fibromuscular dysplasia (FMD) is a nonatherosclerotic, noninflammatory angiopathy of unknown cause affecting medium-sized (most commonly renal) arteries and causing renovascular hypertension. The most common medial multifocal type of FMD (with the “string of beads” appearance) is more than four times more prevalent in females than in males. FMD accounts for up to 10% of cases of renovascular hypertension. Compared with patients with atherosclerotic renal artery stenosis, patients with FMD are younger, have fewer risk factors for atherosclerosis, and a lower occurrence of atherosclerosis in other vessels. The etiology is multifactorial, including vessel wall ischemia and smoking, as well as hormonal and genetic factors. Intra-arterial digital subtraction angiography is still the gold standard for exclusion or confirmation of renal artery stenosis caused by FMD, at least in young patients, who more often have lesions in branches of the renal artery. For FMD patients with atherosclerosis and those who are older (>50–55 years), significant renal artery stenosis may be confirmed or excluded with ultrasonography. The FMD lesion is typically truncal or distal, whereas atherosclerotic lesions are more often proximal or ostial. Treatment options are medical, endovascular (percutaneous transluminal renal angioplasty [PTRA]), and surgical. Invasive treatment should be considered when hypertension cannot be controlled with antihypertensive drugs and in patients with impaired renal function or ischemic nephropathy. PTRA has become the treatment of choice and normally yields good results, especially in unifocal disease and young patients. Pressure gradients are normally completely abolished, and there is no indication for stent placement. Surgical revascularization is indicated after PTRA complications; thrombosis, perforation, progressive dissection, repeated PTRA failure or restenosis. Centralization of handling is recommended.

The role of CT angiography in the evaluation of pediatric renovascular hypertension

Historically, the evaluation of renovascular hypertension has been accomplished by US, renal scintigraphy and digital subtraction angiography. Based on its high accuracy reported in adults renal CT angiography (CTA) with pediatric-appropriate low radiation dose techniques has become an important tool in the workup of renovascular hypertension in children. Renal CTA has several advantages over more conventional imaging modalities, including rapid and non-invasive acquisition, high resolution and easy reproducibility. Additionally, in our experience high-quality renal CTA can be performed using low-dose radiation exposures and can be acquired without sedation in most instances. This article illustrates by examples the usefulness of renal CTA for diagnosis of childhood renovascular hypertension and provides an overview of renal CTA findings in the most common childhood renovascular diseases.

Renovascular hypertension--is it fibromuscular dysplasia or Takayasu arteritis

Renovascular hypertension (RVH) can be caused by many different diseases, with the most common being fibromuscular dysplasia (FMD) and Takayasu arteritis (TA). A strikingly different diagnostic pattern is seen in children with RVH from different parts of the world. In Europe and North America, these children are mainly diagnosed as having FMD while in Asia and South Africa they will most often get a diagnosis of TA. When comparing the clinical diagnosis for FMD and TA, it becomes obvious that there is a great deal of overlap between the definitions of these two conditions. Different ways to come to the most accurate diagnosis using imaging of the blood vessel wall and positron emission tomography (PET) will be discussed. How an accurate diagnosis should influence the treatment of the children with these conditions will also be addressed.

Unmasking of neonatal renovascular hypertension by milrinone used for cardiac dysfunction

A neonate initially presented with heart failure, with severe cardiac dysfunction confirmed by echocardiography, at 3 days of age. Blood pressure at presentation was in the high normal range. It was not until there was a rapid improvement of left-ventricular function on intravenous milrinone that the infant was noted to be hypertensive on day of life 7. It is noteworthy that milrinone, a drug with vasodilator and inotropic properties, paradoxically unmasked hypertension by rapidly improving left-ventricular function. Subsequent work-up showed the etiology of hypertension to be left renal artery stenosis. We present this case to alert clinicians to the rarer causes of left-ventricular dysfunction and to point out that its etiology, i.e., hypertension, may not be apparent until there is improvement in the systolic function of the left ventricle.

Renal artery stenosis: is angiography still the gold standard in 2011?

Renovascular hypertension (RVH) is an unusual cause of hypertension in children that is important to diagnose as it is potentially curable with angioplasty or surgery. Digital subtraction angiography is the gold standard for diagnosing RVH; for other methods like ultrasound, isotope studies, magnetic resonance angiography and computed tomography angiography sensitivity is still too low to reliably exclude RVH. Clinical and laboratory criteria that suggest RVH will be proposed and recommendations when digital subtraction angiography should be performed will be made. A treatment algorithm that suggests when to use medical treatment, interventional radiology and surgery in children with RVH will be given.

Renal autotransplantation for the treatment of renovascular hypertension in the pediatric population

PURPOSE

To evaluate the effectiveness of renal autotransplantation (RA) for the treatment of renovascular hypertension (RVH) in a selected group of children in whom medical care, a percutaneous transluminal angioplasty or vascular reconstruction failed or was technically impossible, in addition to the short-term and long-term morbidity.

MATERIALS AND METHODS

A retrospective case review of 13 pediatric patients with severe or complicated RVH who underwent RA between May 1993 and August 2008 was conducted. We defined blood pressure (BP) response as follows: Cured: normal BP values with no need of antihypertensive medication (AM); Improved: normal BP values with AM requirements; Failed: abnormal BP values despite treatment with AM.

RESULTS

16 RA were performed in 7 female and 6 male patients. Bilateral RA were performed in 2 females and in 1 male. The average age at consultation for hypertension was 8.5 years (range 4-12 years) and the time of transplantation was 9.12 years (range 6-13 years). Etiological diagnoses were: Takayasu disease (n = 5); renal artery fibrodysplasia (n = 3); mid-aortic syndrome (n = 3) and neurofibromatosis type I (n = 2). Results after RA were: Cured: 61.5%; Improved: 38.5%. No patient presented therapeutic failure during follow up time (median = 53.4 months). Only 1 case presented a postoperative complication.

CONCLUSIONS

RA is a procedure with no mortality and low morbidity rates that renders very satisfactory therapeutic results in the pediatric population.

Captopril-enhanced renal scintigraphy in the diagnosis of pediatric hypertension

Hypertension in childhood is no longer a rare condition mainly secondary to renal, or renovascular diseases, as a growing proportion of children are obese and hypertensive, with the phenotype of metabolic syndrome. Thus, we need to reconsider our practice in the examination of the hypertensive child and redefine the place of non-invasive methods for screening of renovascular hypertension, and specifically, to evaluate the value of captopril-enhanced renal scintigraphy at the two ends of the palette: the obese child with hypertension and the severely hypertensive prepubertal child. Renal artery stenosis in children is mainly due to fibromuscular dysplasia and stenoses associated with syndromes involving single or multiple smaller branch vessels. This explains the low specificity and sensitivity of the color-Doppler ultrasound method and captopril renal scintigraphy. Even the more sophisticated computed tomography (CT) and magnetic resonance imaging (MRI) angiographic techniques are, at present, not sensitive enough to exclude stenoses of the small branches definitely. Thus, children in whom there is a strong suggestion of renovascular hypertension should undergo angiography with a view to endovascular treatment, as non-invasive imaging has no significant benefit and might lead to a delay in treatment. In the cases when the probability of renovascular disease is moderate a basic assessment of renal function and structure is sufficient. In the neonate, catheter-associated thromboembolic disease is among the most common causes hypertension. It should be controlled medically until the patient is old enough to undergo angiography and angioplasty successfully. Thus, in this age group, there is a place for functional imaging with renal sonography and angiotensin-converting enzyme inhibitor (ACEI) renography to detect hemodynamically significant renovascular disease, with the limitations mentioned above. However, the rapid technical evolution of non-invasive methods requires periodic re-consideration of the actual standpoints.

Cutting balloon angioplasty of bilateral renal artery stenosis due to Takayasu arteritis in a 5-year-old child with midterm follow-up

The aim of this report is to demonstrate the successful endovascular treatment of bilateral renal artery stenosis due to Takayasu arteritis by cutting balloon angioplasty in a 5-year-old child with mid-term follow-up.

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.

Hypertension and segmental renal infarction in children: apropos of two cases

Segmental renal infarction (SRI) is a rare condition that causes renovascular hypertension (RVH), which accounts for 8-10% of all causes of pediatric hypertension. We report the clinical course of two children with idiopathic SRI who suffered severe arterial hypertension associated with hyponatremia. Hypertension was diagnosed during the study of hematuria in the first case and due to a hypertensive emergency in the second case. The etiology was found to be renovascular in both patients, involving the occlusion of small renal arteries and causing SRI. Our first patient was treated with partial nephrectomy, and the second patient was treated with antihypertensive medication given the impossibility of removing the infarcted renal area. The occlusion of small renal arteries is a rare disease of unknown origin in which the gold standard for diagnosis is selective renal arteriography. The definitive treatment is surgical segmentectomy. If segmentectomy is not feasible because of the localization of the infarcted area, as in our second patient, medical treatment is required. In view of the importance of RVH in children and the rareness of the particular etiology here reported (SRI), a review of the literature was done.

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.

Vascular abnormalities in patients with neurofibromatosis syndrome type I: clinical spectrum, management, and results

PURPOSE

Neurofibromatosis type I (NF-I) is an autosomal dominant disorder affecting one in 3000 individuals. Vascular abnormalities are a well-recognized manifestation of NF-I. The purpose of this study is to review the spectrum, management, and clinical outcome of patients with vascular abnormalities and NF-I.

METHODS

We retrospectively reviewed 31 patients (15 males, 16 females) with clinical NF-I and vascular abnormalities identified from imaging or operative findings between 1976 and 2005.

RESULTS

The diagnosis of NF-I was made at a mean age of 11 +/- 10 years with vascular lesions identified at a mean age of 38 +/- 16 years. There were 76 vascular abnormalities, including 38 aneurysms, 20 arterial stenoses, 5 arteriovenous malformations (AVM), 5 arteries compressed or invaded by neural tumors, and 6 abnormalities of the heart valves. Arterial lesions were located in the aorta (n = 17) and in the renal (n = 12), mesenteric (n = 12), carotid-vertebral (n = 10), intracerebral (n = 4), and subclavian-axillary and iliofemoral arteries (3 each). Interventions were required in 23 patients (74%); 15 underwent 24 arterial reconstructions, including 9 renal, 8 aortic, 4 mesenteric, 2 carotid, and 1 femoral. The other eight patients had excision of AVM in three, vessel ligation in two, and clipping of cerebral aneurysms, coil embolization of hepatic aneurysms, and left thoracotomy in one patient each. One patient died of ruptured abdominal aortic aneurysm. Six patients (26%) had postoperative complications, including pneumonia in two, and stroke, acalculous cholecystitis, brachial plexopathy and chylothorax in one patient each. The median follow up was 4.1 years (range, 6 months to 20 years). Late vascular problems developed in three patients, including graft stenoses in two and rupture of another aortic aneurysm in one. Freedom from graft-related complications was 83% at 10 years. Patient survival at 10 years was 77%, less than the 86% expected survival for the general population (P < .001).

CONCLUSION

Patients with NF-I have a wide spectrum of vascular abnormalities, most notably aneurysms or stenoses of the aortic, renal, and mesenteric circulation. Operative treatment of symptomatic patients with vascular lesions or large aneurysms is safe, effective, and durable.

Pediatric renovascular hypertension: 132 primary and 30 secondary operations in 97 children

PURPOSE

This study was undertaken to characterize the contemporary surgical treatment of pediatric renovascular hypertension.

METHODS

A retrospective analysis was conducted of the clinical data of 97 consecutive pediatric patients (39 girls, 58 boys), aged from 3 months to 17 years, who underwent operation at the University of Michigan from 1963 to 2006. All but one patient had refractory hypertension not responsive to contemporary medical therapy. Developmental renal artery stenoses accounted for 80% of the renal artery disease, with inflammatory and other ill-defined stenoses encountered less frequently. Splanchnic arterial occlusive lesions affected 24% and abdominal aortic coarctations, 33%.

RESULTS

Primary renal artery operations were undertaken 132 times. Procedures included resection beyond the stenosis and implantation into the aorta in 49, renal artery in 7, or superior mesenteric artery in 3; aortorenal and iliorenal bypasses with vein or iliac artery grafts in 40; focal arterioplasty in 10; resection with reanastomosis in 4; operative dilation in 4; splenorenal bypass in 2; and primary nephrectomy in 13 when arterial reconstructions proved impossible. Bilateral renal operations were done in 34 children, and 17 underwent celiac or superior mesenteric arterial reconstructions, including 15 at the time of the renal operation. Thirty patients underwent abdominal aortic reconstructions with patch aortoplasty (n = 19) or thoracoabdominal bypass (n = 11). Twenty-five of the aortic procedures were performed coincidently with the renal operations. Thirty secondary renal artery procedures were done in 19 patients, including nine nephrectomies. Hypertension was cured in 68 children (70%), improved in 26 (27%), and was unchanged in three (3%). Follow-up averaged 4.2 years. No patients required dialysis, and there were no operative deaths.

CONCLUSION

Contemporary surgical treatment of pediatric renovascular hypertension emphasizes direct aortic implantation of the normal renal artery beyond its stenosis and single-staged concomitant splanchnic and aortic reconstructions when necessary. Benefits accompany carefully executed operative procedures in 97% of these children.

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

BACKGROUND

Renal artery stenosis (RAS) causes significant hypertension in children. Frequently, pediatric RAS occurs with systemic disorders. In these cases, stenoses are often complex and/or include long segments. We believed that hypertensive children without comorbid conditions had a different lesion distribution and that the difference might have implications for imaging and treatment.

OBJECTIVE

To identify locations of RAS lesions in these hypertensive children without comorbid conditions.

MATERIALS AND METHODS

Patients who had renal angiography for hypertension from 1993 to 2005 were identified. Patients with systemic disorders, renovascular surgery, or normal angiograms were excluded. The angiograms of the remaining patients were reviewed for number, type, and location of stenoses.

RESULTS

Eighty-seven patients underwent renal angiography for hypertension; 30 were excluded for comorbid conditions. Twenty-one of the remaining 57 patients had abnormal angiograms; 24 stenoses were identified in those patients. All were focal and distributed as follows: 6 (25%) main renal artery, 12 (50%) 2nd order branch, 3 (12.5%) 3rd order branch, and 3 (12.5%) accessory renal artery.

CONCLUSION

Hypertensive children without comorbid conditions who have RAS usually have single, focal branch artery stenoses. This distribution supports angiography in these patients because of its superior sensitivity in detecting branch vessel disease and its therapeutic role in percutaneous transluminal renal angioplasty.

Unilateral renal ischemia causing the hyponatremic hypertensive syndrome in children--more common than we think?

A case report in the journal Pediatric Nephrology describes a 15-month-old girl with the syndrome of hypertension and hyponatremia (HH syndrome) due to underlying unilateral renal artery stenosis. This syndrome is typically associated with hypokalemia and severe volume depletion and sometimes proteinuria, all of which, along with hypertension and hyponatremia, are usually corrected by resolution of the underlying renal ischemia. Gross and probably sudden activation of the renin-angiotensin system in response to renal ischemia is central to the pathophysiology although the cardiac atrial and B-type natriuretic peptides probably contribute also. Initial control of the severe hypertension may, in some cases, require careful volume repletion prior to introduction of blockade of the renin-angiotensin system in order to avoid first-dose hypotension, after which correction of the underlying renal ischemia is required. Whereas the syndrome has rarely been reported in children, it is possible that, as in adults, this reflects its lack of recognition by clinicians. The HH syndrome due to unilateral renal ischemia in children may be much more common than we think.

Angioplasty for renovascular hypertension in children: 20-year experience

OBJECTIVE

Our aim was to evaluate the clinical outcomes, safety, and efficacy of percutaneous transluminal angioplasty for renovascular hypertension in children.

METHODS

A retrospective review of data for all children with renovascular hypertension who underwent percutaneous transluminal angioplasty at a single center between 1984 and 2003 was performed. Patients with renal transplants and inflammatory multisystem diseases were excluded.

RESULTS

Thirty-three children, 1.9 to 17.9 years of age (median: 10.3 years), underwent renal angioplasty and/or stenting. Underlying syndromes were present in 10. On angiograms, 16 had bilateral renal artery stenosis, 15 intrarenal disease, 8 aortic stenosis, and 7 cerebrovascular disease. Forty-eight percutaneous transluminal angioplasty procedures were performed, including 15 stenting procedures. There was a high rate of restenosis after stenting (7 of 19 cases, compared with 2 of 27 cases after balloon dilation). Outcomes were cured (ie, blood pressure normal without treatment) for 9 patients, improved blood pressure with same or reduced treatment for 7, blood pressure maintained in >95th percentile because of cerebrovascular disease for 2, no change in blood pressure despite technical success for 10, and technical failure for 5. Blood pressure control improved in 11 of 13 children who had main renal artery disease alone and in 6 of 20 with associated intrarenal disease or stenoses in other vascular beds. There was 1 procedure-related death and 5 minor complications.

CONCLUSIONS

Angioplasty produced clinically worthwhile improvement for approximately 50% of patients. High incidence rates of extrarenal involvement and intrarenal disease and a high restenosis rate after stenting accounted for poor blood pressure control in the rest.

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

The clinical course of two children with mid-aortic syndrome and renal artery stenosis (RAS) who suffered from severe arterial hypertension is described. Hypertension was uncontrollable by antihypertensive medication and was managed by percutaneous transluminal renal angioplasty (PTRA) with stent implantation. The pediatric experience with PTRA is limited, and there are only few cases reported with additional stent implantation. Complications of these procedures are well known from experience with adult patients. However, since surgical revascularization may be technically difficult especially in small children, PTRA with or without stenting should be considered as a valuable treatment option in pediatric RAS.

Screening for hypertension in high school

Arterial hypertension is a major risk factor for atherosclerotic ischemic heart disease and cerebrovascular stroke. Blood pressure measurements were taken in the supine position in 6,282 healthy adolescents (3073 boys, 3209 girls) aged 13-17 years of both sexes. Forty-eight subjects were found to have hypertension: 35 idopathic and 13 secondary to reflux nephropathy, chronic glomerulonephritis, coarctation of the aorta, and hemolytic uremic syndrome. Systolic blood pressure was significantly higher among males than females at ages 15-17 years (p<0.001); diastolic blood pressure was higher among males at age 17 years only (p<0.05). Males with BMI>17 exhibited higher systolic blood pressure than females. Prevalence of hypertension, mostly primary, in a large cohort of students was 0.76%. Early screening is important for early interventions and reducing cardiovascular morbidity and mortality in adulthood.

Percutaneous transluminal angioplasty for renovascular hypertension in a neonate

AIM

To report on the first case of successful percutaneous transluminal renal artery angioplasty in a neonate.

METHODS

CASE REPORT

a 5-d-old neonate was admitted with cardiorespiratory failure. Monitoring of blood pressure revealed severe arterial hypertension. Doppler sonography detected stenotic flow in the right renal artery. A (99m)Tc-MAG3 scan revealed highly diminished elimination by the right kidney. Selective renin levels were 23,968 ng/l in the right and 3770 ng/l in the left renal vein and the aorta. Percutaneous transluminal angioplasty using a 2 x 10 mm balloon catheter was performed on the 8th day of life.

RESULTS

The patient was discharged from hospital normotensive without anti-hypertensive medication. During 8 mo follow-up the blood pressure remained normal, Doppler sonography revealed no recurrent artery stenosis, and renal function improved.

CONCLUSION

Neonatal percutaneous transluminal angioplasty for renal artery stenosis may be feasible in selected patients.

Renovascular disease in children and adolescents

PURPOSE

This retrospective review describes the surgical management of renovascular disease in 25 consecutive children and adolescents with severe hypertension.

METHODS

Patients </=21 years of age (mean age, 11.6 +/- 5.4 years; 12 females, 13 males) underwent repair of 34 renal arteries (RAs), and their management forms the basis of this report. Early and late blood pressure responses were adjusted for gender, age, and height. RA repair was evaluated by angiography, renal duplex sonography (RDS) scanning, or both. Primary patency and survival were estimated by product-limit methods.

RESULTS

Thirty-four RAs among 32 kidneys were repaired. Bilateral renal RA disease to a solitary kidney was present in nine patients. RA lesions included dysplasia (44%), RA hypoplasia (20%), midaortic syndrome (12%), RA aneurysm (12%), dissection (8%), and arteritis (4%). All patients had severe hypertension (>95 th percentile systolic or diastolic pressure adjusted for gender, age, and height). RA repair comprised 25 bypasses (73%) consisting of 28% saphenous vein, 60% hypogastric artery, and 12% polytetrafluoroethylene; 2 patch angioplasties (6%), and 7 reimplantations (21%). Branch RA exposure was required in 28 kidneys (88%), and branch reconstruction was required in 61%. Warm in situ repair was used in 53%, in situ cold perfusion in 24%, and ex vivo cold perfusion in 23%. Of six bilateral RA repairs, one was staged and two patients are awaiting a staged repair. Combined aortic reconstruction was required in three patients. No unplanned nephrectomy was performed. There were no perioperative deaths. Hypertension was cured in 36%, improved in 56%, and failed in 8% at mean follow-up of 46.4 +/- 7.8 months. The mean calculated glomerular filtration rate increased from 82.0 mL/min/1.73 m 2 preoperatively to 98.2 mL/min/1.73 m 2 postoperatively. The postoperative patency of 30 RA reconstructions was evaluated by angiography, RDS scanning, or both. At mean follow-up of 32.8 months (median, 21.2 months), primary RA patency was 91%. No failures were observed after 2 months follow-up. Estimated survival was 100% at 60 months, with one death 9 years after surgery.

CONCLUSIONS

Renovascular hypertension in children and adolescents was caused by a heterogeneous group of lesions. All patients had RA repair, with arterial autografts in most of the RA bypasses. Cold perfusion preservation was used in half of the complex branch RA repairs. These strategies provided 91% primary patency at mean follow-up of 32.8 months, with beneficial blood pressure response in 92%. Surgical repair of clinically significant renovascular disease in children and adolescents is supported by these results.

Renal artery stenosis and aneurysms associated with neurofibromatosis

Renal artery lesions associated with neurofibromatosis may involve stenosis and aneurysm formation at all levels of the renal artery to the intraparenchymal branches, and usually are associated with hypertension. A 13-year-old boy with type I neurofibromatosis and severe hypertension presented with multiple aneurysms and multiple stenotic lesions in the renal artery and segmental arteries. The patient underwent ex-vivo renal artery repair with autologous hypogastric artery and autotransplantation to the iliac fossa and was clinically improved. The characteristic histologic findings are presented. A review of the recent literature comparing different treatment modalities for renovascular hypertension in children with neurofibromatosis suggests that surgery remains the best treatment alternative.

Interventional radiology for renovascular hypertension in children

Pediatric renovascular hypertension is an uncommon but important clinical problem. Atherosclerosis is rare in children, who typically suffer from fibromuscular dysplasia, neurofibromatosis type 1, Williams syndrome, or certain other rare conditions. Children with renovascular disease often have involvement of other arteries including the aorta and mesenteric and cerebral vessels. The pediatric interventional radiology service has a vital role in the diagnosis, evaluation, and treatment of renovascular hypertension. Renal vein renin sampling appears to be more useful in children than in adults, because their arterial disease is more often bilateral and segmental. Diagnostic angiography is still superior to less-invasive methods of imaging the renal arteries, especially the smaller branches. Interventional options include angioplasty, stenting, and ethanol ablation. Angioplasty is almost always technically successful and usually gives a worthwhile clinical improvement. Stenting is only used in children when angioplasty fails. Ethanol embolization may be appropriate in children with focal renin-producing areas that are untreatable by angioplasty.

Tuberous sclerosis complex and neurofibromatosis type 1: the two most common neurocutaneous diseases

TSC and NF1 are the most common of the neurocutaneous diseases, and both are autosomal dominant with a high spontaneous mutation rate. For diagnosis, two features are necessary for each disease. Skin findings for each are especially helpful for diagnosis, as is neuroimaging in TSC. For NF1, neuroimaging is not yet reliable for diagnosis. In children, brain symptoms cause most of the morbidity in TSC, and nerve sheath and nervous system tumors as well as learning disabilities cause major morbidity in NF1. Renal disease becomes a serious problem for adults with TSC. The TSC1, TSC2, and NF1 genes function as tumor suppressor genes and have other functions that are being investigated. Blood tests for diagnosis have a high false-negative rate. Therapies for TSC and for NF1 are both medical and surgical.

Hypertension in children

Abstract. Hypertension is a major public health issue in industrialized nations, affecting approximately 20% of adults. Hypertension often begins in childhood, and children with hypertension are very likely to be seen with this disorder as adults. The close associations of hypertension with atherosclerosis, coronary and cerebrovascular disease, diabetes and end-stage renal disease make it a major contributor to the most common causes of morbidity and mortality in adult population. (1) According to many studies performed in adult populations, the effective treatment of hypertension reduces the risk of coronary heart disease, stroke, renal disease and congestive heart failure. (2)

Tuberous sclerosis complex and neurofibromatosis type 1: the two most common neurocutaneous diseases

TSC and NF1 are the most common of the neurocutaneous diseases, and both are autosomal dominant with a high spontaneous mutation rate. For diagnosis, two features are necessary for each disease. Skin findings for each are especially helpful for diagnosis, as is neuroimaging in TSC. For NF1, neuroimaging is not yet reliable for diagnosis. In children, brain symptoms cause most of the morbidity in TSC, and nerve sheath and nervous system tumors as well as learning disabilities cause major morbidity in NF1. Renal disease becomes a serious problem for adults with TSC. The TSC1, TSC2, and NF1 genes function as tumor suppressor genes and have other functions that are being investigated. Blood tests for diagnosis have a high false-negative rate. Therapies for TSC and for NF1 are both medical and surgical.

Successful management of a resistant renal artery stenosis in a child using a 4 mm cutting balloon catheter

Percutaneous transluminal renal angioplasty (PTRA) is a well-established method to treat renal artery stenosis (RAS) in children and adults. However, a significant number of stenoses might not be treated by interventional techniques due to the inability to dilate the RAS. Conventional balloon angioplasty with a high-pressure coronary angioplasty balloon at 20 atm was unable to dilate a significant RAS in a 12-year-old child with severe renovascular hypertension (RR 195/125 mm Hg). After using a 4 mm cutting balloon, we achieved wide patency of the renal artery and an instant normalization of blood pressure without further need of antihypertensive therapy. PTRA using the cutting balloon technique may offer an additional therapeutic option for selected patients in whom conventional balloon angioplasty was not able to dilate RAS.