Can peripheral stents be used for renal artery stenting in patients with atherosclerotic disease and significant stenosis?

Renal Artery Stenting: Stent Selection and Technical Approach

For atherosclerotic renal artery stenosis requiring intervention, dedicated renal stents (not peripheral stents designed for lower extremity use) should be used, with primary stenting being the established standard approach for ostial atherosclerotic lesions. 1

Stent Type Recommendations by Etiology

Atherosclerotic Disease

• Primary stent placement is recommended for ostial atherosclerotic renal artery stenosis (Class I, Level B recommendation), as stenting has consistently proven superior to balloon angioplasty alone for these lesions 1
• Balloon-expandable stents (such as the Palmaz stent) are the traditional choice for ostial lesions, providing precise deployment and radial strength needed for aorto-ostial disease 2
• Self-expanding nitinol stents designed for renal use are also appropriate options 1
• Drug-eluting stents have NOT demonstrated significant benefit over bare-metal stents for renal artery stenosis and should be restricted to clinical trials given lack of outcome data, additional cost, and need for prolonged dual antiplatelet therapy 1, 3

Fibromuscular Dysplasia

• Balloon angioplasty WITHOUT stenting is the treatment of choice (Class IIa, Level C recommendation) 1, 4
• Stenting should only be used as bailout for suboptimal angioplasty results (dissection, elastic recoil, residual stenosis) 1, 4

Critical Technical Considerations

Stent Sizing

• Intravascular ultrasound (IVUS) is strongly recommended for optimal stent sizing to avoid the competing risks of undersizing (higher restenosis rates) versus oversizing (vessel rupture and dissection) 1
• Undersizing may be safer but leads to restenosis rates of 6-20% 3
• Proper sizing is critical as restenosis rates range from 3.5% to 20% depending on vessel diameter and stent selection 1

Hemodynamic Assessment

• For moderate stenoses (50-69% diameter), hemodynamic confirmation is mandatory using pressure wire or ≤5-Fr catheter 1
• Significant gradients are defined as: resting systolic gradient ≥20 mmHg, resting mean gradient ≥10 mmHg, or hyperemic gradients exceeding these thresholds 1
• Severe stenoses (≥70% diameter) are considered hemodynamically significant without pressure measurement 1

Clinical Indications for Stenting (Must Meet BOTH Clinical AND Anatomic Criteria)

Clinical Criteria Requiring Intervention

• Resistant hypertension on ≥3 maximally tolerated antihypertensive medications (including a diuretic) 1
• Flash pulmonary edema or recurrent unexplained heart failure despite maximal medical therapy 1
• Progressive chronic kidney disease with bilateral stenosis or stenosis in solitary kidney 1
• Accelerating decline in renal function with hemodynamically significant bilateral or solitary kidney stenosis 1

Anatomic Criteria

• Stenosis ≥70% diameter by visual estimation 1
• Stenosis 50-69% diameter WITH hemodynamic confirmation (gradients as above) OR post-stenotic dilatation 1

Common Pitfalls to Avoid

Wrong Patient Selection

• Newly diagnosed atherosclerotic RAS should receive optimal medical therapy FIRST, not immediate stenting 1
• Patients with well-controlled hypertension or those on <3 antihypertensive medications are rarely appropriate candidates 1
• Incidentally discovered RAS without clinical manifestations should NOT be stented (considered Rarely Appropriate) 1
• Revascularization is rarely appropriate for small (<7 cm pole-to-pole) nonviable kidneys 1

Technical Errors

• Using peripheral lower extremity stents instead of dedicated renal stents risks inappropriate sizing and mechanical properties for the renal circulation 1
• Performing stenting without IVUS guidance increases risk of sizing errors 1
• Failing to measure pressure gradients in moderate (50-69%) stenoses leads to inappropriate intervention 1

Procedural Considerations

• Procedures should be performed in experienced centers due to high risk of restenosis and technical complexity 1
• Distal protection devices remain controversial with no proven benefit except possibly when combined with glycoprotein IIb/IIIa inhibitors 1

Post-Procedure Management

• Initial follow-up at 1 month, then every 12 months or when new symptoms arise 1
• Duplex ultrasound surveillance at ≤30 days, 6±1 months, ≤12±1 months, then annually 1
• Re-intervention may be considered for in-stent restenosis ≥60% with recurrent symptoms (diastolic BP >90 mmHg on >3 medications or >20% increase in creatinine) 1