Renovascular hypertension in children: current concepts in evaluation and treatment

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.

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.

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.

Segmental renal artery stenosis diagnosed with captopril renography in a child

A 9-year-old girl with clinical suspicion of renovascular hypertension was referred for captopril renography. This showed a segmental abnormality when the left kidney was analyzed as two separate cortical regions of interest. Subsequent angiography confirmed stenosis in the distal mid and lower pole branches of the left renal artery.

Staged reconstruction for middle aortic syndrome

BACKGROUND/PURPOSE

Middle aortic syndrome is a rare condition that involves narrowing of the abdominal aorta and its visceral branches. The authors propose staged vascular repair to minimize renal ischemia and facilitate use of native arterial tissue for reconstruction.

METHODS

Three adolescents (age 8(1/2), 12(1/2), 13(1/2)) presented with severe hypertension. Subsequent evaluation showed coarctation of the abdominal aorta extending above the celiac axis. All 3 patients had bilateral renal artery stenoses. There also were tight stenoses of the celiac or superior mesenteric arteries. In the first stage the right renal artery stenosis was relieved. In the youngest patient, this was accomplished by balloon angioplasty. However, in the other 2, right renal autotransplantation was performed to the right iliac vessels using end-to-side anastomoses of the renal artery and vein. Cold perfusion was used. The second stage was performed 2 to 5 months later via a thoracoabdominal approach in 2 patients. A Dacron tube graft was utilized from above the coarctation to the iliac bifurcation. The left renal arteries were detached and anastomosed end to side to the bypass graft. In 1 child there were actually 3 separate renal arteries that required reimplantation. In the youngest patient the aortic narrowing was relieved by a long Dacron patch aortoplasty and interposition of an internal iliac artery graft to the left renal artery.

RESULTS

All 3 patients recovered well and returned to full activities. There was no measurable rise of BUN or serum creatinine postoperatively. Postoperative renal scans showed good renal perfusion bilaterally. Follow-up results 2 to 10 years later continue to show well functioning reconstructions.

CONCLUSION

A staged approach is an effective reconstruction for children with middle aortic syndrome which minimizes risk to renal function.

The surgical management of renovascular hypertension in children and young adults

OBJECTIVES

To assess the outcome and durability of operative revascularisation in young patients with renovascular hypertension.

DESIGN

Retrospective study.

METHOD

The records of all young patients (under 25 years) operated on for renovascular hypertension at St Mary's Hospital 1988-1998 were reviewed. We assessed the aetiology of hypertension, operations performed, effect of treatment on blood pressure, renal function and requirement for antihypertensive medication during follow-up.

RESULTS

Ten patients were identified who had been considered for surgery, of median age 16 years (22 months to 22 years). Fibromuscular dysplasia was present in five patients, mid-aortic syndrome (MAS) in four and neurofibromatosis in one. Operations performed were aortorenal bypass (three), aorto-aortic bypass+/-renal bypass (three), splenorenal bypass (one) and autotransplantation (one). Of the three patients treated by balloon angioplasty, only one had a successful result. One patient with MAS is currently awaiting surgery. Over a median follow-up of 24 months (8-144), seven patients are normotensive off all antihypertensive medication. Of two patients on reduced doses of medication, one (splenorenal bypass) required surgical repair of a late (9 years) coeliac stenosis.

CONCLUSIONS

The surgical treatment of renovascular hypertension in carefully selected young patients gives durable results. Blood pressure is well controlled long-term, and the need for antihypertensive medication is removed altogether in the majority of patients.

Renal artery stenosis in infants: long-term medical treatment before surgery

This report describes five infants (3 male, 2 female) with renal artery stenosis diagnosed in their 1st year of life. The age at initial presentation was 5 days to 10 months. All had symptoms of congestive heart failure, cardiomegaly on chest X-ray, and left ventricular hypertrophy by electrocardiogram or echocardiogram. Renograms were abnormal in four of the five infants. An intravenous pyelogram was obtained in three infants and was abnormal in two. Renal ultrasounds were obtained in two infants and were normal in both. Patients were treated for 4.4 +/- 0.9 years with antihypertensive drug therapy until surgical correction of the renal artery stenosis. Blood pressure was persistently elevated above the 95th percentile in four of the infants during the course of antihypertensive therapy prior to surgery. Patients have been followed for 9.4 +/- 2 years since surgery. The blood pressure of four patients is normal, and the blood pressure of the oldest patient (age 23 years) is borderline hypertensive. These data show that infants with renal artery stenosis can be cared for successfully with long-term antihypertensive drug therapy to preserve renal mass with minimal chronic adverse effects.

Arterial stents in the management of neurofibromatosis and renovascular hypertension in a pediatric patient: case report of a new treatment modality

A 17-year-old male with neurofibromatosis presented with severe hypertension secondary to an abdominal aortic coarctation and bilateral renal artery stenoses. Despite previous surgical bypass grafts and aggressive medical management, including treatment with diuretics, beta-blocker, calcium channel blocker, angiotensin converting enzyme (ACE) inhibitors, and direct vasodilator agents, severe hypertension persisted. Following intravascular stent placement in the aorta and both renal arteries, blood pressures normalized.

Pediatric renovascular hypertension: a thirty-year experience of operative treatment

PURPOSE

This study was undertaken to characterize the changing operative treatment of pediatric renovascular hypertension and subsequent outcomes in a 30-year experience at a single institution.

METHODS

Clinical data were analyzed on 57 pediatric patients, 24 girls and 33 boys, ranging in age from 10 months to 17 years, who underwent operations for renovascular hypertension from 1963 to 1993 at the University of Michigan. Renal artery disease included atypical medial-perimedial dysplasia, often with secondary intimal fibroplasia (88%), and inflammatory mural fibrosis (12%). Abdominal aortic narrowings affected 15 patients. Data were categorized into three chronologic eras (I:1963-1972, II:1973-1980, and III:1981-1993) to allow identification of therapeutic trends.

RESULTS

Primary surgical procedures were undertaken 74 times. Ex vivo reconstruction was necessary once. Primary operations included aortorenal bypass with autogenous vein grafts (n = 26) or internal iliac artery grafts (n = 7); iliorenal bypass with vein grafts (n = 2); renal artery resection beyond the stenosis and reimplantation into the aorta (n = 10), the main renal artery (n = 2), an adjacent segmental renal artery (n = 3), or the superior mesenteric artery (n = 3); renal artery resection and reanastomosis (n = 3); focal renal arterioplasty (n = 2); operative dilation (n = 7); splenorenal bypass (n = 2); and primary nephrectomy (n = 7). Among 23 primary operations performed in era I, 56.5% were aortorenal bypasses with vein grafts, but in era III this form of revascularization represented only 3% of 33 primary operations. No reimplantations were performed in era I, whereas reimplantations accounted for 51.5% of era III procedures. Thirteen patients underwent staged or concomitant aortic reconstructions with thoracoabdominal aortoaortic bypass grafts (n = 5) or patch aortoplasty (n = 8). Fourteen patients underwent a total of 20 secondary operations, including seven secondary nephrectomies. Operative therapy benefited 98% of these children: hypertension was cured in 45 (79%), improved in 11 (19%), and unchanged in one (2%). There were no operative deaths.

CONCLUSIONS

Contemporary surgical management emphasizes direct reimplantation of main renal arteries into the aorta, reimplantation of segmental arteries into adjacent renal arteries, patch aortoplasty for associated abdominal aortic coarctations, and single-stage revascularizations. Pediatric patients with renovascular hypertension clearly benefit from carefully executed operative therapy.

Renovascular hypertension in children

Renal arteriography remains the only study to identify and define correctly both location and extent of renal artery stenosis. Because other studies do not adequately identify all children who have renal artery disease, it is reasonable to perform renal arteriography in those children with severe hypertension who do not have another readily identifiable cause for their hypertension. On the other hand, in children with less profound elevation of blood pressure in whom there is no other definable cause, it is possible to defer renal angiography. In these children with mild or moderate hypertension, studies such as the captopril 99mTc-DTPA scan or intravenous digital subtraction angiography may identify those for whom arteriography is more likely to have abnormal results.

Renovascular disease in childhood

Fifty-four children referred for investigation of hypertension had renovascular disease. In eight patients it was associated with neurofibromatosis, in three with idiopathic hypercalcemia of infancy, and in five cases it followed an arteritic illness. Fibromuscular dysplasia was the underlying abnormality in the majority of cases (46%). Twenty-six patients (48%) were first seen with accelerated hypertension; 38 children (70%) had bilateral renal arterial disease, and in 41 (76%), disease of the small intrarenal vessels was found. Renal vein renin ratios indicated unilateral disease in 31 cases; the results correlated with arteriography findings in 32 (62%) of 51 patients. Eleven children also had the middle aortic syndrome, and 9 of 16 patients, investigated by cerebral arteriography because of cranial bruits or focal neurologic signs, had cerebral vascular abnormalities. Twenty patients were treated surgically--10 by reconstructive procedures, 11 by nephrectomy or heminephrectomy, and 6 by transluminal angioplasty. Of these, 9 (45%) are normotensive with no treatment, 10 have a decreased requirement for antihypertensive drugs, and 1 had no improvement. Thirty-four patients were treated medically because of the extent of their disease; two patients have died of hypertensive complications. We conclude that renal vascular disease in children is often widespread, may be associated with intracerebral vascular disease, frequently affects both kidneys, including both intrarenal and extrarenal vessels, and is therefore not always amenable to surgical intervention and cure.

Experience with bilateral renal artery stenosis as a cause of hypertension in childhood

Since 1981, eight children have been treated at this hospital for hypertension due to bilateral renal artery stenosis (RAS). Useful diagnostic studies were DTPA renal scan following pretreatment with captopril, and selective renal angiography. All patients underwent attempted surgical revascularization of the RAS and three had aortoaortic bypass of an abdominal aortic narrowing. Of the 14 kidneys that had repair of RAS, a successful outcome was obtained in 11 (80%). Three patients required unilateral nephrectomy. Five of eight patients are normotensive and off all medications, and three are normotensive on reduced medication doses.