Renal artery stenosis

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. more...

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

• pheochromocytoma
• Cushing's syndrome
• essential hypertension
• kidney failure

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

• balloon angioplasty and stent
• surgery (rarely used)

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