History
Patients with renovascular hypertension (RVHT) may be asymptomatic, and the hypertension may be discovered during routine examination or preparation for surgical treatment of another problem. In most pediatric studies, more than one half of children who were found to be hypertensive were asymptomatic, or their hypertension was discovered during a routine examination. When symptoms are present, they are nonspecific and are often related to the organ systems most affected by hypertension.
The most common symptom of RVHT seems to be headache. Other neurologic symptoms include altered mental status, vision changes, vomiting, seizures, coma, encephalopathy, hyperexcitability, and hyperirritability. Symptoms of congestive heart failure (eg, decreased energy, edema, and shortness of breath) may also develop. In patients with abdominal aortic narrowing, claudication may be present. Some children have anorexia, and infants or young children often present with failure to thrive. Occasionally, patients have oliguric renal failure.
Clinical risk factors for RVHT include the following:
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A history of hypertension with azotemia (serum creatinine level >1.5 mg/dL) and modest proteinuria (levels < 1.5 g/day)
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Progressive renal insufficiency
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Accelerated or malignant hypertension
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Severe hypertension (diastolic blood pressure >120 mm Hg)
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Hypertension with an asymmetric kidney
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Paradoxical worsening of hypertension with diuretic therapy
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Hypertension refractory to standard therapy
The following are common findings from the history:
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Onset of hypertension occurring in patients younger than 30 years without risk factors
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Abrupt onset of severe (stage II) hypertension (greater than 160/100 mm Hg in patients older than 55 years)
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Severe or resistant hypertension despite appropriately dosed multidrug (>3 agents) antihypertensive therapy
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Abrupt increase in blood pressure over previously stable baseline in patients with previously well-controlled essential hypertension, as well as patients with known renal artery stenosis (RAS)
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Negative family history for hypertension
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Smoking tobacco products
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Acute sustained rise in serum creatinine levels with angiotensin-converting enzyme (ACE) inhibitor therapy
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Unprovoked hypokalemia (serum potassium level < 3.6 mEq/L, often associated with metabolic alkalosis)
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Symptoms of atherosclerotic disease at other sites, in the presence of moderate-to-severe hypertension, particularly in patients older than 50 years
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Recurrent pulmonary edema in the setting of moderate-to-severe hypertension
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Moderate-to-severe hypertension in a patient with an unexplained atrophic kidney, significantly asymmetric kidneys (>1.5 cm difference), or diffuse atherosclerosis
Physical Examination
Findings suggestive of long-standing hypertension may or may not be evident upon physical examination. Such findings may include the following:
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Recurrent flash pulmonary edema or unexplained episodes of congestive heart failure
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Advanced funduscopic changes
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Abdominal bruit – A clear abdominal bruit is heard in 46% of patients with RVHT, as well as in 9% of patients with essential hypertension; however, innocent bruits are common in younger individuals; systolic-diastolic bruits in combination with hypertension are suggestive of RVHT
Upon physical examination, pediatric patients have a blood pressure elevation above the 95th percentile for their age, sex, and height. Generally, children with blood pressures higher than 140/100 mm Hg are thought to be more likely to have secondary hypertension, and RVHT is more likely in children with higher blood pressure.
Eye examination may reveal retinopathy and retinal hemorrhages. Patients with heart failure may present with tachypnea, cardiomegaly, and vasomotor instability leading to mottling and acrocyanosis. Lower-extremity pulses may be diminished with aortic coarctation, whether thoracic or abdominal.
An enlarged liver may be palpated, and an abdominal bruit may be auscultated. Patients with tumors impinging on renal vasculature may present with an abdominal mass in the area of the kidney. Rarely, signs or symptoms of visceral artery involvement are present because of the extensive collateralization that occurs.
Café-au-lait macules are classic findings in the presentation of neurofibromatosis. Patients with neurofibromatosis may also have macrocephaly, neurofibromas, dermal neurofibromas, and axillary freckling.
Complications
RVHT can develop into chronic hypertension, and patients usually present with malignant hypertension. If left untreated, this can produce serious consequences, including coma and death. Chronic hypertension can damage blood vessels, leading to such pathology as plaques, aneurysms, claudication, and dissection.
The main comorbidity of RVHT is directly related to its capacity to lead to end-organ damage. Neurologic manifestations are often the presenting symptoms because severe hypertension can lead to retinopathy, headaches, dizziness, confusion, seizures, and stroke. The heart is frequently affected because increased afterload leads to congestive heart failure and ventricular hypertrophy.
Renovascular hypertension may also damage the kidneys, especially when significant stenosis of the perfusing vessels is present. Although they are rare, oliguric renal failure and ischemic kidneys have been reported with renovascular disease.
Finally, RVHT is often associated with failure to thrive in young children.
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Magnetic resonance angiography (MRA) showing renal artery stenosis. Courtesy of Patricia Stoltzfus, MD, Chief of Interventional Radiology, West Virginia University.
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Proposed pathogenesis of renovascular hypertension.
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Angiogram showing bilateral renal artery stenosis. Courtesy of Department of Radiology, Henry Ford Hospital.
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After percutaneous transluminal angioplasty (right renal artery). Courtesy of Department of Radiology, Henry Ford Hospital.
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After percutaneous transluminal angioplasty and stent placement (left renal artery). Courtesy of Department of Radiology, Henry Ford Hospital.
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Close-up of the Palmaz stent. Courtesy of Department of Radiology, Henry Ford Hospital.
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Aortogram of 4-year-old child with renovascular hypertension caused by stenosis of left renal artery. Note that left kidney has 2 renal arteries and that artery to superior pole has stenosis.
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Close-up view of aortogram of 4-year-old child. Stenotic lesion begins at ostium of left superior renal artery. This lesion was caused by fibromuscular dysplasia and did not respond well to balloon angioplasty.
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Operative photograph of 4-year-old child. Patient underwent aortorenal bypass with reinforced saphenous vein graft. Inferior pole renal artery was preserved.
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Aortogram of 8-year-old child with neurofibromatosis and renovascular hypertension caused by right renal artery stenosis.
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Operative photograph of 8-year-old child. Aortorenal bypass was performed with Dacron-reinforced saphenous vein graft. Aorta is completely exposed, and graft is visible inferior to native renal artery.
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Although nephrectomy is rarely indicated in treatment of renovascular hypertension in children, it can be safely performed with modern pediatric surgical laparoscopy technique. This 3-month-old child with renal dysplasia and refractory hypertension underwent laparoscopic nephrectomy. Photograph illustrates patient positioning and placement of small trocars at time of nephrectomy. Dysplastic kidney was easily removed through slightly enlarged umbilical incision.
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3-month-old child immediately after laparoscopic nephrectomy. This patient was discharged from hospital 2 days after surgery. This approach eliminates need for large incisions and facilitates recovery from surgery, minimizing pain and length of hospital stay.
