Guidelines Summary
The following organizations have released guidelines for the management of renal artery stenosis (RAS):
-
American College of Cardiology (ACC)/American Heart Association (AHA)
-
European Society of Cardiology (ESC)
-
Society for Cardiovascular Angiography and Interventions (SCAI)
Diagnosis
The 2013 ACC/AHA and 2017 ESC guidelines recommend performing diagnostic studies to identify RAS in patients with any of the following [66, 67] :
-
Onset of hypertension before the age of 30
-
Onset of severe hypertension after the age of 55
-
Accelerated hypertension (sudden and persistent worsening of previously controlled hypertension)
-
Resistant hypertension
-
Malignant hypertension (hypertension with coexistent end-organ damage; ie, acute kidney injury, flash pulmonary edema, hypertensive left ventricular failure, aortic dissection, new visual or neurological disturbance, and/or advanced retinopathy)
-
New azotemia or worsening renal function after the administration of an angiotensin-converting enzyme (ACE) inhibitor or an angiotensin receptor blocker (ARB)
-
Unexplained atrophic kidney or size discrepancy of greater than 1.5 cm between the kidneys
-
Unexplained renal failure
-
Flash pulmonary edema
The ACC/AHA guidelines define resistant hypertension as failure of blood-pressure control despite full doses of an appropriate three-drug regimen including a diuretic. [66] The ESC defines it as failure to achieve target blood pressure despite use of four drug classes, including a diuretic and a mineralocorticoid receptor antagonist in appropriate doses, in cases where another form of secondary hypertension is unlikely. [67]
The ESC also lists the combination of hypertension and abdominal bruit as a possible indication of RAS. [67]
In its 2014 SCAI Expert Consensus Statement for Renal Artery Stenting Appropriate Use, the SCAI utilized the ACC/AHA recommendations. [68]
Class I recommendations for establishing a diagnosis of RAS generally concur and include the following [66, 67] :
-
Duplex ultrasonography (DUS) is the first-line test
-
Computed tomography angiography in patients with creatinine clearance >60 mL/min
-
Magnetic resonance angiography in patients with creatinine clearance >30 mL/min
When the clinical index of suspicion is high and the results of noninvasive tests are inconclusive, ACC/AHA recommends catheter angiography, [66] while ESC recommends digital subtraction angiography. [67]
Both guidelines are in agreement that captopril renal scintigraphy, selective renal vein renin measurements, plasma renin activity, and the captopril test are not recommended as useful screening tests for RAS (class III). [66, 67]
SCAI recommends renal angiography as the gold standard for invasive assessment of hemodynamically significant RAS and categorizes stenosis severity as follows [68] :
-
Mild: < 50%
-
Moderate: 50–70%
-
Severe: >70%
Severe angiographic stenosis is considered hemodynamically significant. Moderate angiographic stenosis is considered hemodynamically significant only when the patient also has a resting mean pressure gradient >10 mm Hg or systolic hyperemic pressure gradient >20 mm Hg or renal fractional flow reserve (FFR) ≤0.8. Mild and moderate stenosis that is not hemodynamically significant should only rarely be considered for revascularization. [68]
Medical Therapy
ACC/AHA, ESC and SCAI all prefer medical therapy as the first-line treatment for RAS. [66, 67, 68] ACC/AHA and ESC recommend ACE inhibitors, ARBs, and calcium channel blockers for unilateral RAS, [66, 67] but ESC advises that patients with bilateral severe RAS or RAS in a single functional kidney require very careful monitoring when started on ACE inhibitors or ARBs. [67]
The ACC/AHA also recommends beta-blockers for treatment of hypertension associated with RAS. [66] The ESC considers the use of antiplatelet agents to be part of best medical therapy. [67]
Revascularization
The ACC/AHA guidelines recommend percutaneous revascularization in patients with hemodynamically significant RAS and any of the following [66] :
-
Recurrent congestive heart failure or sudden unexplained pulmonary edema (class I)
-
Unstable angina (class IIa)
-
Accelerated, resistant, or malignant hypertension or hypertension with unexplained unilateral small kidney and intolerance to medication (class IIa)
-
Asymptomatic bilateral or single functioning kidney; however, this treatment is clinically unproven in asymptomatic unilateral hemodynamically significant RAS in a viable kidney (class IIb)
In addition, percutaneous revascularization is reasonable for patients with progressive chronic kidney disease (CKD) and bilateral RAS or a RAS to a single functioning kidney and can be considered for unilateral RAS with chronic renal insufficiency. [66] The ESC also recommends revascularization in patients with symptomatic fibromuscular dysplasia who have signs of organ ischemia. [67]
ACC/AHA and ESC recommend renal stent placement for ostial atherosclerotic RAS (class I). [66]
ACC/AHA gives a class I recommendation for balloon angioplasty with bailout stent placement if necessary for fibromuscular dysplasia lesions; [66] whereas ESC recommends considering balloon angioplasty with or without stenting for patients with RAS and recurrent congestive heart failure or sudden pulmonary edema and preserved systolic left ventricular function (class IIb).{ref55)
Based on an expert panel review of scientific data, the SCAI concluded that patients with the following are most likely to benefit from renal artery stenting [68] :
-
Cardiac disturbance syndromes (flash pulmonary edema or acute coronary syndrome)
-
Hypertension that has not been controlled by three or more medications at maximal tolerated doses
-
Blockages in both kidneys or severe blockages in a single functioning kidney where blood pressure or renal dysfunction cannot be managed medically
The SCAI concluded that patients with any of the following are typically not good candidates for renal artery stenting [68] :
-
Mild or moderate blockages (less than 70%)
-
Long-standing loss of blood flow
-
Complete blockage of the renal artery
ACC/AHA gives class I recommendations to surgical revascularization for the following indications: [66]
-
Fibromuscular dysplasia, especially in those exhibiting complex disease or macroaneurysms
-
Atherosclerotic RAS and multiple small renal arteries or early primary branching of the main renal artery
-
Atherosclerotic RAS in combination with pararenal aortic reconstruction
ESC gives a class IIb recommendation to consider surgical revascularization in patients undergoing repair of the aorta or with complex anatomy of renal arteries or after failure of endovascular treatment. [67]
-
Renal artery stenosis/renovascular hypertension. Left, Sonograms of the kidneys on a 57-year-old woman with difficult-to-control hypertension shows kidneys of uneven sizes: The left kidney is 96 mm, and the right kidney is 63 mm. Top right, Isotopic renogram (obtained with technetium mercaptoacetyltriglycine [MAG3]) after captopril shows a markedly depressed renal function in the right kidney. Bottom right, Analogous images show negligible activity in the right kidney. Note that this pattern is more typical for DTPA than MAG3 (as DTPA depends on the glomerular filtration rate for uptake which is decreased after captopril in renovascular hypertension [RVHT]). In severe cases of RVHT, MAG3 uptake can be decreased, as in this case. However, typically, uptake is preserved with decreased cortical excretion.
-
Renal artery stenosis/renovascular hypertension. Left, Flush aortogram in a 63-year-old man with hypertension shows marked stenosis of the right renal artery and complete occlusion of the left renal artery. Note the extensive atheroma in the aorta and iliac arteries. Right, nephrogram-phase image shows a significantly smaller left kidney with a faint nephrogram. Some blood supply to the left kidney is retained via collaterals (see image on the left).
-
Renal artery stenosis/renovascular hypertension. Flush aortogram in a 32-year-old man with familial hypercholesterolemia and difficult-to-control hypertension. Radiograph shows a complete occlusion of the right renal artery and marked stenosis of the left renal artery (arrow).
-
Three-dimensional gadolinium-enhanced magnetic resonance angiograms (MRAs) show medial fibroplasia, which appears as classic string-of-beads sign. This sign is due to multiple stenoses with intervening outpouchings that form a chain. In this case, the lesions involve the main right renal artery and the right accessory renal artery in a 37-year-old man with difficult-to-control hypertension.
-
Conventional flush aortogram in a 47-year-old woman with difficult-to-control hypertension shows the characteristic string-of-beads sign (arrows) of the right renal artery due to medial fibroplasia.
