• Clinical science

Renal artery stenosis

Summary

Renal artery stenosis is the narrowing of one or both renal arteries. It is most commonly caused by atherosclerosis. In young women, fibromuscular dysplasia is an important underlying cause. Decreased renal blood flow due to renal artery stenosis causes activation of the renin-angiotensin-aldosterone system, which in turn results in secondary hypertension. Physical examination may reveal an abdominal bruit. Patients with progressive renal artery stenosis develop renal insufficiency and progressive renal atrophy. Hypokalemia in a newly diagnosed case of hypertension or an abrupt increase in creatinine after initiating ACE inhibitors or angiotensin receptor blockers is suggestive of renal artery stenosis. The diagnosis is confirmed by duplex ultrasonography or angiography. Treatment of mild renal artery stenosis primarily consists of antihypertensive therapy. The antihypertensives of choice are paradoxically ACE inhibitors and angiotensin receptor blockers; calcium channel blockers or beta-blockers can also be used. Patients on ACE inhibitors or angiotensin receptor blockers should be closely monitored for an increase in serum creatinine, especially if they have bilateral renal artery stenosis. Patients with severe renal artery stenosis will require renal angioplasty.

Epidemiology

  • Accounts for 1–10% of all hypertension cases. [1]
  • 3–10% of pediatric cases of secondary hypertension have a renovascular etiology. [2]
  • Age and sex preponderance depend on the underlying cause (see “Etiology” below).

Epidemiological data refers to the US, unless otherwise specified.

Etiology

Pathophysiology

Clinical features

Diagnostics

Laboratory findings

Imaging (confirmatory test) [3]

  • Indications [9][10]
    • Onset of hypertension before the age of 30 years or after 55 years
    • New-onset renal dysfunction or worsening of renal function with ACEi or ARBs
    • Unexplained renal atrophy or asymmetry of > 1.5 cm between kidneys
    • Hypertension that is resistant to a 3-drug antihypertensive regimen
  • Imaging modality [9][11][10]
    • First-line: non-invasive imaging
    • Second-line: invasive catheter angiography
  • Findings

Treatment

Patients with atherosclerosis should reduce risk factors by statin therapy and lifestyle modification.

Antihypertensive therapy [9]

Closely monitor serum creatinine especially in patients with bilateral renal artery stenosis. ACE inhibitor or ARB treatment should be terminated if rapid and/or severe worsening of kidney function occurs.

Revascularization procedures [9][14]