Renal artery stenosis resident survival guide

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Karol Gema Hernandez, M.D. [2]

Definition

Renal artery stenosis is defined as a dimished diameter of the lumen of the renal artery. There are different degrees of stenosis. Shown below there is a table that depicts the degree of stenosis according to the percentage of the lumen occluded. [1][2]

Severity Luminal Narrowing
Normal 0%
Mild 1-49%
Moderate 50-69%
Severe 70-99%
Occluded 100%

Renal artery stenosis can also be classified by hemodynamic function. Shown below there is a table rewarding hemodynamic function.[3]

Hemodynamically significant RAS
≥70% by visual estimation
≥70% by intravascular ultrasound measurement
50-70% RAS with a systolic gradient of ≥20 mm Hg or a mean gradient of ≥10 mm Hg.

Causes

The primary goal of treating renal artery stenosis, either medically or by revascularization (surgical or percutaneous), is to prevent ischemic nephrophathy, and ultimately to diminish the presentation of clinical end points that may lead to all cause mortality.

Clinical Clues to the Diagnosis of RAS

 
 
 
 
 
❑ Determine if one or more of the above is present
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
ScenarioLevel of evidence
1.Onset of hypertension before the age of 30 years or severe hypertension after the age of 55Class I; LOE B
2. Accelerated, resistant, or malignant hypertensionClass I; LOE C
3. Development of new azotemia or worsening renal function after administration of an ACE inhibitor or ARB agentClass I; LOE B
4. Unexplained atrophic kidney or size discrepancy between kidneys of greater than 1.5 cmClass I; LOE B
5. Sudden, unexplained pulmonary edemaClass I; LOE B
6. Unexplained renal dysfunction, including individuals starting renal replacement therapyClass IIa; LOE B
7. Multi-vessel CADClass IIb; LOE B
8. Unexplained CHFClass IIb; LOE C
9. Refractory anginaClass IIb; LOE C
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
❑If one or more of the above are present, proceed to further diagnostic testing
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Noninvasive Imaging
 
 
 
Invasive Imaging
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
❑ Duplex ultrasound

❑ Gadolinium enhanced MRA

❑ CT angiography
 
 
 
❑ Abdominal aortography to assess the renal arteries during coronary and peripheral angiography
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Negative noninvasive test but with high clinical suspicion
 
Evidence of RAS
 
Evidence of RAS
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Evidence of RAS
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Confirmed RAS, proceed to treatment
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Algorithm based on the 2013 AHA Guidelines Recommendations for Management of Patients with PAD.[3]

Treatment

Treatment can be medical therapy alone or medical therapy plus angioplasty/stenting. However, recent studies reveal that although there are high technical success rates with angioplasty/stenting, the clinical end points are inconsistently and modestly modified. [4] Therefore, raising the suspicion that PRI (percutaneous renal interventions) can incur in substantial costs without a significant public health advantage. The present algorithms are based in the most updated guidelines of the 2013 AHA Guidelines Recommendations for Management of Patients with PAD.

Medical Therapy

Indications for Renal Revascularization

Indication Level of Evidence
1.Hemodynamically significant RAS (see table above) with recurrent, unexplained CHF or sudden, unexplained pulmonary edema Class I; LOE B
2. RAS with:
  • Accelerated, resistant, or malignant hypertension
  • Hypertension with unilateral small kidney
  • Hypertension with medication intolerance
 Class IIa; LOE B
3.RAS and CRI with bilateral RAS or RAS to solitary functioning kidney Class IIa; LOE B
4. RAS and unstable angina Class IIa; LOE B
5. Asymptomatic bilateral or solitary viableʰ kidney with a hemodynamically significant RAS Class IIb; LOE C
6. Asymptomatic unilateral hemodynamically significant RAS in a viable* kidney Class IIb; LOE C
7. RAS and CRI with unilateral RAS (2 kidneys present) Class IIb; LOE C


ʰViable means kidney linear length greater than 7 cm.


Shown below there is an algorithm of therapeutic options after any of the indications for revascularization are met.

 
 
 
 
 
 
 
 
❑ Presence of one or more indications for revascularization:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
❑Renal Angioplasty/Stent
 
 
 
❑ Renal artery surgery
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Atherosclerotic RAS
 
 
 
Fibromuscular dysplasia RAS
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Renal stent placement is indicated for ostial atherosclerotic RAS lesions that meet the clinical criteria for intervention
 
 
 
Balloon angioplasty with bailout stent placement if necessary is recommended for fibromuscular dysplasia lesions
 


Algorithm based on the 2013 AHA Guidelines Recommendations for Management of Patients with PAD.[3]

References

  1. ↑ Kliewer MA, Tupler RH, Carroll BA, Paine SS, Kriegshauser JS, Hertzberg BS; et al. (1993). "Renal artery stenosis: analysis of Doppler waveform parameters and tardus-parvus pattern". Radiology. 189 (3): 779–87. doi:10.1148/radiology.189.3.8234704. PMID 8234704.
  2. ↑ Desberg AL, Paushter DM, Lammert GK, Hale JC, Troy RB, Novick AC; et al. (1990). "Renal artery stenosis: evaluation with color Doppler flow imaging". Radiology. 177 (3): 749–53. doi:10.1148/radiology.177.3.2243982. PMID 2243982.
  3. ↑ 3.0 3.1 3.2 Anderson JL, Halperin JL, Albert NM, Bozkurt B, Brindis RG, Curtis LH; et al. (2013). "Management of patients with peripheral artery disease (compilation of 2005 and 2011 ACCF/AHA guideline recommendations): a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines". Circulation. 127 (13): 1425–43. doi:10.1161/CIR.0b013e31828b82aa. PMID 23457117.
  4. ↑ Cooper CJ, Murphy TP, Cutlip DE, Jamerson K, Henrich W, Reid DM; et al. (2014). "Stenting and medical therapy for atherosclerotic renal-artery stenosis". N Engl J Med. 370 (1): 13–22. doi:10.1056/NEJMoa1310753. PMID 24245566.


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