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Renal artery stenosis is the narrowing of the renal artery. It is caused by atherosclerosis or fibromuscular dysplasia. This can lead to atrophy of the affected kidney. It can lead to renal failure, if not treated. It is often unmasked by the rapid worsening of renal function in response to the administration of a drug from the ACE inhibitor class.
Diagnosis
- refractory hypertension - high blood pressure that can not be controlled adequately with antihypertensives
- auscultation (with stethoscope) - bruit ("rushing" sound) on affected side, inferior of the costal margin
- captopril challenge test
- renal artery arteriogram
Etiology
Atherosclerosis is the predominant cause in the older patients, fibromuscular dysplasia is the predominant cause in young patients.
Differential diagnosis
Pathophysiology
The macula densa of the kidney senses a decreased systemic blood pressure due to the pressure drop over the stenosis. The response of the kidney to this decreased blood pressure is activation of the renin-angiotension aldosterone system, which normally counter acts low blood pressure, but in this case lead to hypertension (high blood pressure). The decreased perfusion pressure (caused by the stenosis) leads to decreased blood flow (hypoperfusion) to the kidney and a decrease in the GFR. If the stenosis is long standing and severe the GFR in the affected kidneys never increases again and (pre-renal) renal failure is the result.
Treatment
Treatment of renal artery stenosis may be necessary if the blood pressure cannot be controlled medically, or the renal function deteriorates. Nordmann et al (2003) found that angioplasty with stenting was safe and effective in this context. Surgical resection and anastomosis is a rarely-used option.
See also
Reference
- Nordmann AJ, Woo K, Parkes R, Logan AG. Balloon angioplasty or medical therapy for hypertensive patients with atherosclerotic renal artery stenosis? A meta-analysis of randomized controlled trials. Am J Med 2003;114:44-50. PMID 12557864.
External links
- Renal Artery Stenosis - emedicine.com
"Renal artery stenosis"