Renal artery stenosis (RAS) refers to the occlusion or narrowing of the intima of the major artery that supplies blood to the kidneys. The resulting hypoperfusion of the kidneys can lead to chronic renal insufficiency and end-stage renal disease (ESRD). RAS can lead to renovascular hypertension, the most common cause of secondary hypertension (i.e., hypertension caused by an identifiable underlying secondary cause).

The two main causes of RAS are atherosclerotic renovascular disease (ASRD) and fibromuscular dysplasia (FMD). In ASRD, the renal arterial wall is lined with fatty material that thickens, hardens, and eventually causes partial or complete blockage of blood flow to the kidneys. In FMD, a combination of hormonal and mechanical effects causes arterial fibrosis. Both conditions can result in hypoperfusion of the affected kidney and activate the renin-angiotensin-aldosterone system, which ultimately increases blood pressure (BP). Potential complications of RAS include chronic renal failure, heart failure, hypertensive encephalopathy, and aneurysm.

Renal angiography is the gold standard for diagnosing RAS, although the increasing use of noninvasive tests, including CT angiography and magnetic resonance angiography (MRA), has reduced the need for invasive diagnostic procedures.

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