Renal artery stenosis resident survival guide

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 of >70% is considered hemodynamically significant.

Causes

Life Threatening Causes

Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated. Renal artery stenosis does not have life threatening causes.

Common Causes

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

Managment of RAS

Clinical Clues to the Diagnosis of RAS

Determine if one or more of the following is present: ❑ Onset of hypertension before the age of 30 years ❑ Onset of severe hypertension after the age of 55 ❑ Accelerated, resistant, or malignant hypertension ❑ Development of new azotemia or worsening renal function after administration of an ACE inhibitor or ARB agent ❑ Unexplained atrophic kidney or size discrepancy between kidneys >1.5 cm ❑ Sudden, unexplained pulmonary edema ❑ Unexplained renal dysfunction, including individuals starting renal replacement therapy ❑ Multi-vessel CAD ❑ Unexplained CHF ❑ Refractory angina

❑ Proceed with non-invasive imaging

Is the patient allergic to contrast?

Yes

No

Does the patient has any of the following? ❑ Implanted devices: - Pacemakers - Defibrillators - Cochlear implants - Spinal cord stimulators ❑ Claustrophobia

No

Yes

❑ Proceed with US

❑ Proceed with MRA

❑ Proceed with CT

Inconclusive noninvasive test but with high clinical index of suspicion: ❑ Perform catheter angiography

Confirmed RAS: ❑ Proceed to treatment

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

Treatment

Initiate a regimen that combines: ❑ Tight blood pressure control to <130/80 mmHg (120/75 mmHg if proteinuria is present) with: ACEI ARB CCB beta blockers ❑ Control of hyperlipidemia (LDL cholesterol <70 mg/dl) with statins ❑ Glycemic control (Hemoglobin A1c <7%) ❑ Antiplatelet agents ❑ Life style modifications: Smoking cessation counseling Normalization of body weight

Proceed to evaluate clinical indications for revascularization:

❑ RAS with: - Accelerated, resistant, or malignant hypertension - Hypertension with an unexplained unilateral small kidney - Hypertension with medication intolerance ❑ Progressive CKD with bilateral RAS or RAS to a solitary functioning kidney ❑ Hemodynamically significant RAS with recurrent, unexplainedCHF or sudden, unexplained pulmonary edema ❑ Unstable angina ❑ Asymptomatic bilateral or solitary viable kidney ❑ CRI with unilateral RAS

If any of the above AND: ❑ Ostial atherosclerotic RAS OR ❑ Fibromuscular dysplasia

If any of the above AND: ❑ Complex fibromuscular dysplasia disease that extends into segmental arteries OR ❑ Macroaneurysms OR ❑ Atherosclerotic RAS with multiple small renal arteries or early primary branching of the main renal artery

Endovascular treatment

Renal artery surgery

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

References

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