Indications
  • Uncontrolled or worsening hypertension of unclear etiology
  • Hypertension of probable renal cause not controlled on antihypertensives 
  • Progressive unilateral renal atrophy.
  • Renal artery thrombosis.
  • Renal trauma requiring angiographic management.​

Contraindications
  • Advanced renal failure with limited function.
  • Creatinine >3–4 mg/dL.
  • Severe bleeding diathesis or uncorrectable coagulopathy.
  • Consider delaying intervention in infants <10 kg when feasible.
  • For angioplasty: long segment stenosis, arterial aneurysm.

Pre-Procedure
Clinical Evaluation:
  • All patients should be evaluated in the renal artery / mid-aortic stenosis center.
  • Review of anti-hypertensive medications.
  • Arrange for admission to ICP if angioplasty planned.

​Imaging:
  • Baseline Doppler ultrasound of the kidneys for all patients.​ ​
Picture
14 year old girl admitted with hypertensive urgency. Spectral Doppler traces from the main renal arteries demonstrate markedly elevated PSV in the proximal left MRA
Picture
Left arcuate artery Doppler demonstrates decreased resistive index and a parvus tardus waveform.

 
Cross sectional imaging,
  • CTA preferred to determine:
    1. Number of renal arteries.
    2. Location, length, and degree of stenosis.
    3. Associated disease of the aorta, celiac axis and SMA.
Picture
CTA reformat of left renal artery.
  • Consider MRA is CTA contraindicated (elevated creatinine), but MRA has decreased specificity, particularly in smaller children
  • MAG3 scan for differential renal function.
  • Brain MRI if history of neurofibromatosis or risk of rapid BP drop post-procedure.

​Medication Doses
Calculate doses of commonly used medications before procedure, write on a note and place in procedure room.
  • Heparin 75–100 U/kg bolus
  • Alteplase (0.1 mg/kg)
  • Nitroglycerin 1–2 µg/kg for complications
  • Contrast: ≤5–6 mL/kg total (prefer ~3 mL/kg if renal impairment)

Labs
  • CBC.
  • BUN, creatinine, electrolytes.
  • Coagulation profile (PT, INR, PTT).
  • Type & screen (crossmatch if angioplasty planned)

Technique
Protocol
  • Confirm patient positioning and access plan.
  • Review cross-sectional imaging to determine level of renal arteries, best angulation, and accessory arteries, 
  • Request general anesthesia with paralysis.
  • Select balloon size and sheath/catheter requirements.
  • Prepare necessary rescue devices and stents for bailout use.
Consent
  • Include diagnostic angiography, angioplasty, possible stent placement, embolization, and renin sampling if indicated.
Access
  • Femoral artery standard; radial/brachial/axillary access if femoral unsuitable or anatomy dictates.
  • Document pulses in extremity to be accessed.
Anticoagulation
  • Heparin bolus 75–100 U/kg IV prior to dilation if angioplasty planned. Monitor ACT. Consider 50U/kg IV bolus at time of sheath insertion if patient <10 kg.
Contrast
  • Limit total dose to ~5–6 mL/kg (prefer ~3 mL/kg if renal impairment). Use low frame rate, biplane imaging to conserve contrast.
Picture
Aortogram demonstrates normal appearance of the aorta and right renal artery and confirms stenosis on the left.
​Angiography

​Abdominal aortogram
  • Multi-sidehole calibrated flush catheter (4–5F pigtail/SOS) below SMA.
  • Contrast: 1–1.5 mL/kg over 2 s, max adjusted for size.
  • DSA during apnea; use bowel motion suppression if needed.

Selective renal angiography
  • Catheter: 4–5F Cobra, Simmons, or reverse curves.
  • At least one frontal and two oblique projections coned to kidney. Use pre-procedure CTA to assess optimal obliquity.
  • Assess parenchymal and venous phases in at least one projection.
  • At least one projection should demonstrate reflux of contrast into the aorta.
  • Evaluate all accessory renal arteries.
  • DSA at 4 frames/sec for 4 seconds and 1/s after.
  • Paralysis with apnea during DSA.
  • Administer glucagon (10 ug/kg) to decrease artifacts from movement of bowel. Consider re-dosing as needed.
​
Picture
Selective left renal arteriogram shows stenosis of the mid renal artery, with a beaded appearance suggestive of fibromuscular dysplasia.

Angioplasty
Picture
Post angioplasty arteriogram demonstrates resolution of renal artery stenosis.
Picture
Angioplasty of the left renal artery.

 If bilateral disease, consider staging. Re-evaluate during the procedure following angioplasty of first kidney.
  • An angled guiding sheath or catheter (e.g. Envoy) can be advanced to near the ostium of the artery to be treated.
  • If available, pressure measurement can be performed across a stenosis using a pressure wire or microcatheter.  A pressure gradient of 9 mm Hg or more is significant.
  • If available, IVUS can be used for further assessment of stenosis.
  • Advance a microguidewire (0.014” Stabilizer) and exchange the diagnostic catheter for the angioplasty balloons. The microguidewire should remain across the stenosis until angioplasty has been completed.
  • For most children, balloons are 2-5 mm in diameter.
  • Crosstella (Terumo),  2-6 mm, 5F sheath.
  • Oversize conventional balloons up to 1 mm greater than normal arterial diameter. The measurement should be taken from any pre-stenotic area if available, not post-stenotic dilation.
  • Cutting balloons (Flextome–Boston Scientific) can be used for persistent lesions, but these should not be oversized.
  • Nitroglycerin (1 µg/kg aliquots) for spasm.

Renal Artery Stenting
  • Discouraged in children except for trauma/rupture or failed angioplasty.
  • Oversize ~20% above normal artery diameter.
  • Choose balloon-mounted stents appropriate for vessel size.

​Renal Vein Renin Sampling
  • Indications: persistent hypertension with inconclusive imaging or when lateralization will influence management.
  • Access: femoral or IJ vein, 4F sheath.
  • Catheter: 4F Kumpe/Cobra; use microcatheter in small patients.
  • Sites: infrarenal IVC, main renal veins, segmental branches.
  • Discard first 1–2 mL, collect 2–3 samples per site.
  • Interpretation:
  • Ipsilateral:contralateral ratio >1.5 → hypersecretion.
  • Contralateral:IVC ratio <1.3 → suppression.

Sheath Removal
  • Check ACT if heparin within 1 h; remove sheath if ACT <180.
  • Manual compression for 15 min. Closure devices are not advisable in children.
  • Ultrasound to confirm hemostasis and document site complications.
  • Place Safeguard (inflated to suggested volume (40 ml, 7 ml)). Deflate at 2 hours and re-inflate if persistent oozing.​

Complications
Thrombosis/Occlusion
  • Site-directed alteplase 0.1 mg/kg bolus.
  • Vasodilator (e.g., nitroglycerin 1–2 µg/kg).
Dissection
  • Maintain wire position, re-inflate balloon, anticoagulate.
  • Consult vascular surgery if flow not restored.
Perforation/Rupture
  • Re-inflate balloon to tamponade.
  • Consider covered stent or surgical repair.
Contrast-Induced Nephropathy
  • Monitor urine output and renal function at 24, 48, and 72 h.​

Post-Procedure
  • PACU with BP monitoring.
  • Deflate hemostatic device at 2 h; re-inflate if oozing.
  • Lie flat time: 2 hours, unless angioplasty, then up to 4 hours.
  • Discharge:
    • Diagnostic angiogram only → 2–4 h if stable.
    • Angioplasty → admit overnight to ICP.
  • If angioplasty perform give prophylactic anticoagulation with LMWH for 2 doses.
  • Repeat ultrasound the morning after the procedure. If no evidence of compromised flow to the kidney, discontinue LMWH.
  • Antiplatelet: aspirin 81 mg daily or clopidogrel (37.5 mg daily after 75 mg load) for ~1 month.

Follow-up
  • Nephrology at 1 month.
  • Doppler ultrasound at 4 weeks and 6 months.
  • Long-term BP monitoring.

References
  1. Kari JA, Roebuck DJ, McLaren CA, Davis M, Dillon MJ, Hamilton G, Shroff R, Marks SD, Tullus K. Angioplasty for renovascular hypertension in 78 children. Arch Dis Child. 2015;100(5):474-478. doi:10.1136/archdischild-2013-305886
  2. Donaldson JS. Renal Arteriography and Interventions. In: Temple M, Marshalleck FE, eds. Pediatric Interventional Radiology: Handbook of Vascular and Non-Vascular Interventions. Springer; 2011:71-90. doi:10.1007/978-1-4419-5856-3_5
  3. McLaren CA, Roebuck DJ. Interventional radiology for renovascular hypertension in children. Tech Vasc Interv Radiol. 2003;6(4):150-157. doi:10.1053/S1084-204X(03)90032-4
  4. Meyers KE, Cahill AM, Sethna C. Interventions for pediatric renovascular hypertension. Curr Hypertens Rep. 2014;16(4):422. doi:10.1007/s11906-014-0422-3
  5. Zhu Y, Ma L, Wang H, et al. Mid- to long-term outcomes following renal artery angioplasty in children and young adults with renal artery stenosis: a retrospective review. Pediatr Nephrol. 2025;40(2):287-298. doi:10.1007/s00467-024-06554-8
  6. Society for Cardiovascular Angiography and Interventions (SCAI). SCAI Expert Consensus Statement on Renal Artery Interventions. Catheter Cardiovasc Interv. 2022;99(7):1759-1775. doi:10.1002/ccd.30016
  7. American Heart Association Council on Hypertension. Revascularization for Renovascular Disease: A Scientific Statement. Hypertension. 2022;79(2):e35-e50. doi:10.1161/HYP.0000000000000206
  8. White CJ, Jaff MR, Haskal ZJ, et al. Indications for Renal Artery Stenting: 2018 Appropriate Use Criteria. J Am Coll Cardiol Intv. 2018;11(1):1-9. doi:10.1016/j.jcin.2017.09.034
  9. Konig K, Gorenflo M, Sigler M, et al. Renin measurements in renal vein blood in children: technique, feasibility and interpretation. Pediatr Nephrol. 2013;28(1):77-83. doi:10.1007/s00467-012-2271-4
  10. Thomsen HS, Morcos SK. Contrast media and the kidney: European Society of Urogenital Radiology guidelines. Br J Radiol. 2020;93(1109):20190811. doi:10.1259/bjr.20190811
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