Items in AFP with MESH term: Renal Artery Obstruction
ABSTRACT: More than 72 million Americans have hypertension, and the majority of these persons have essential hypertension. However, a significant subset has a secondary cause. The most common cause of secondary hypertension is renal vascular hypertension, of which renal artery stenosis is the leading pathology. Up to 5 percent of all occurrences of hypertension are caused by renal artery stenosis, equating to as many as 3.5 to 4 million occurrences in the United States. Detecting renal artery stenosis is particularly important for ensuring that this potentially curable form of hypertension is identified and treated properly. Duplex Doppler ultrasonography is a good screening test in many patients, but it has limitations in larger persons and can overlook small accessory arteries. For patients with normal renal function but a high clinical index of suspicion for renovascular disease, contrast-enhanced magnetic resonance angiography and computed tomographic angiography are the most accurate imaging tests. For patients with diminished renal function, gadolinium-enhanced contrast magnetic resonance angiography is the best imaging test. However, caution is warranted because exposure to gadolinium contrast agents is associated with nephrogenic systemic fibrosis in patients with renal failure. The American College of Radiology has developed appropriateness criteria for imaging tests related to the diagnosis of renal artery stenosis. This article is a summary of the recommendations, with the advantages and limitations of each test.
ABSTRACT: Secondary hypertension is a type of hypertension with an underlying, potentially correctable cause. A secondary etiology may be suggested by symptoms (e.g., flushing and sweating suggestive of pheochromocytoma), examina- tion findings (e.g., a renal bruit suggestive of renal artery stenosis), or laboratory abnormalities (e.g., hypokalemia suggestive of aldosteronism). Secondary hypertension also should be considered in patients with resistant hyper- tension, and early or late onset of hypertension. The prevalence of secondary hypertension and the most common etiologies vary by age group. Approximately 5 to 10 percent of adults with hypertension have a secondary cause. In young adults, particu- larly women, renal artery stenosis caused by fibromuscular dyspla- sia is one of the most common secondary etiologies. Fibromuscular dysplasia can be detected by abdominal magnetic resonance imag- ing or computed tomography. These same imaging modalities can be used to detect atherosclerotic renal artery stenosis, a major cause of secondary hypertension in older adults. In middle-aged adults, aldosteronism is the most common secondary cause of hyperten- sion, and the recommended initial diagnostic test is an aldosterone/ renin ratio. Up to 85 percent of children with hypertension have an identifiable cause, most often renal parenchymal disease. Therefore, all children with confirmed hypertension should have an evaluation for an underlying etiology that includes renal ultrasonography.