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. Renal artery stenosis can also be classified by hemodynamic function. Shown below there is a table rewarding hemodynamic function.[1]

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

Life Threatening Causes

Renal artery stenosis is caused by a heterogenous group of entities, that if left unattended may lead to ischemic nephropathy and consecuently death due to end stage renal disease.

  • Atherosclerosis
  • Fibromuscular dysplasia
  • Neurofibromatosis
  • Vasculitis
  • Congenital bands
  • Radiation

Common Causes

  • Atherosclerosis
  • Fibromuscular dysplasia

Managment of RAS

Clinical Clues to the Diagnosis of RAS

 
 
 
 
 
 
 
 
 
Determine if one or more of the following is present:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1.Onset of hypertension before the age of 30 years or severe hypertension after the age of 55
2. Accelerated, resistant, or malignant hypertension
3. Development of new azotemia or worsening renal function after administration of an ACE inhibitor or ARB agent
4. Unexplained atrophic kidney or size discrepancy between kidneys >1.5 cm
5. Sudden, unexplained pulmonary edema
6. Unexplained renal dysfunction, including individuals starting renal replacement therapy
7. Multi-vessel CAD
8. Unexplained CHF
9. Refractory angina
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
If one of the above are present, proceed with Non- invasive imaging
 
 
 
 
 
 
 
 
If there are no clinical clues, proceed with invasive renal arteriography
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Is patient allergic to contrast
 
 
 
 
 
 
 
 
 
 
 
 
{{{ }}}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
If yes proceed with US
 
If no check for:

❑ Implanted devices:

  • Pacemakers
  • Defibrillators
  • Cochlear implants
  • Spinal cord stimulators
❑ Claustrophobic patient
 
 
 
 
 
 
Abdominal aortography to assess the renal arteries during coronary and peripheralangiography
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
If none of the above proceed with MRA
 
If yes to any of the above, proceed with CT
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Negative noninvasive test but with high clinical suspicion
 
Evidence of RAS
 
 
 
 
 
Evidence of RAS
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Go to invasive imaging
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Evidence of RAS
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Confirmed RAS:

❑Proceed to medical therapy

❑Consider revascularization
 
 
 
 
 
 
 
 
 
 

Algorithm based on the 2013 AHA Guidelines Recommendations for Management of Patients with PAD.[1]

Treatment

Medical/Pharmacological Therapy

The 4 main components of the BMT (best medical therapy) are:

Also, statins, optimal glycemic control, and smoking cessation are of supreme importance.

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 (>7cm) Class IIb; LOE C
7. RAS and CRI with unilateral RAS (2 kidneys present) Class IIb; LOE C


Shown below there is an algorithm of therapeutic options to consider 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.[1]

References

  1. 1.0 1.1 1.2 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.


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