What type of stents are recommended for renal artery stenting?

Stent Types for Renal Artery Stenting

For renal artery stenting, balloon-expandable stents are recommended as the primary choice for ostial atherosclerotic renal artery stenosis, while balloon angioplasty with bailout stenting is recommended for fibromuscular dysplasia lesions. 1

Stent Selection Based on Lesion Type

Atherosclerotic Renal Artery Stenosis

• Balloon-expandable stents are the preferred option for atherosclerotic lesions, particularly for ostial lesions 1

  • Palmaz stents are specifically recommended for precise deployment just cephalad to critical branch arteries 1
  • These stents have demonstrated superior outcomes compared to balloon angioplasty alone:
    • Higher procedural success rates (90% vs 63%) 1
    • Lower restenosis rates (14% vs 48%) 1
    • Better reduction of stenosis (3% residual stenosis vs 29% with balloon alone) 1
    • More effective elimination of pressure gradients 2

• Covered stents (such as Atrium iCast) may be considered for:

  • Recurrent in-stent restenosis 3
  • Unstable atheromatous lesions 3
  • Aneurysms or dissections 3

Fibromuscular Dysplasia (FMD)

• Balloon angioplasty is the primary treatment of choice 1
• Bailout stenting only if necessary after unsuccessful balloon angioplasty 1

Technical Considerations

Stent Sizing and Positioning

• Stent should be sized to match the reference vessel diameter 4
• For ostial lesions, position the stent to extend 1-2 mm into the aorta 4
• Average stent dimensions for renal arteries:
  • Diameter: 5-7 mm (most commonly 6 mm) 2
  • Length: Based on lesion, typically covering 3-5 cm proximal and distal to the lesion 1

Deployment Technique

• Predilate with balloon angioplasty before stent placement 4
• Ensure full expansion of the stent with appropriate pressure 4
• Post-deployment balloon dilation may be needed to maximize stent expansion 4
• Blood pressure should be lowered to 50-60 mmHg during stent expansion 1

Post-Procedure Management

Antiplatelet Therapy

• Dual antiplatelet therapy (DAPT) for at least 1 month after stent implantation 4
• Non-compliance with antiplatelet therapy can lead to stent thrombosis and kidney loss 3

Follow-up Protocol

• Initial follow-up at 1 month 4
• Subsequent follow-up every 12 months or when new symptoms arise 4
• Monitor for restenosis using duplex ultrasound 4
• Consider re-intervention for in-stent restenosis ≥60% 4

Clinical Outcomes and Complications

Success Rates

• Technical success rates of 97-99% have been reported 3, 5
• Primary patency rates at 12 months:
  • Overall: 79-84% 3, 5
  • Iliac arteries: 84% 3
  • Renal arteries: 72-79% 3, 5
• Assisted primary patency rates at 12 months:
  • Overall: 98% 3
  • Renal arteries: 92-98% 3, 5

Potential Complications

• Arterial dissection 4
• Stent thrombosis 5
• Arterial perforation or rupture 5
• Access-site complications (6%): pseudoaneurysm, dissection, bleeding 3
• Restenosis (11.4% overall) 5

Special Considerations

Aortic Dissection Cases

• In aortic dissection with renal involvement, stents may be needed to buttress the flap in a stable position 1
• For chronic dissection, stents may be necessary to keep fenestration open 1
• 14 mm diameter Wallstents are an alternative in these complex cases 1

Renal Trauma Cases

• Percutaneous revascularization with stents has shown better outcomes on renal function than surgical treatment in trauma cases 1
• Peripheral stent grafts may be considered for hemostasis while allowing perfusion of the renal artery distal to the injury site 1

Pitfalls to Avoid

• Not confirming hemodynamic significance before intervention 4
• Unnecessary revascularization in patients who can be managed medically 4
• Stent placement across the superior mesenteric and renal arteries should be avoided to prevent compromising flow to distal branches 1
• Neglecting to monitor for restenosis after revascularization 4
• Failing to maintain antiplatelet therapy, which can lead to stent thrombosis and kidney loss 3

The evidence strongly supports the use of balloon-expandable stents for atherosclerotic renal artery stenosis, particularly for ostial lesions, while reserving balloon angioplasty with bailout stenting for fibromuscular dysplasia.