Steps of Renal Artery Stenting
Renal artery stenting is performed in a stepwise approach, beginning with diagnostic angiography and culminating in stent deployment, with careful attention to technical details to ensure optimal outcomes and minimize complications. 1
Patient Selection and Pre-Procedure Evaluation
Identify appropriate candidates with hemodynamically significant renal artery stenosis (RAS):
- Peak systolic velocity ≥200 cm/s or renal-aortic ratio >3.5 2
- High-risk clinical features (treatment-resistant hypertension, rapidly declining renal function, flash pulmonary edema, or solitary kidney) 1
- Signs of kidney viability (kidney size >8 cm, distinct cortex >0.5 cm, albumin-creatinine ratio <20 mg/mmol, renal resistance index <0.8) 1
Avoid unnecessary intervention in patients with unilateral RAS who can be managed medically 2
Procedural Steps
1. Access and Initial Angiography
- Obtain arterial access (typically femoral artery) using Seldinger technique
- Place an appropriate-sized vascular sheath (6-7 Fr)
- Perform baseline aortography to visualize renal arteries and assess stenosis 1
- Document source-image distance and obtain reference images with calibration markers 1
2. Selective Catheterization
- Engage the renal artery with an appropriate guiding catheter
- Perform selective renal angiography to confirm stenosis location and severity
- Measure translesional pressure gradient (significant if resting mean gradient >10 mmHg, systolic hyperemic gradient >20 mmHg, or renal Pd/Pa ≤0.9) 1
3. Lesion Crossing and Preparation
- Administer anticoagulation (typically heparin)
- Cross the stenosis with an appropriate guidewire (0.014" or 0.018")
- Consider embolic protection device placement for high-risk lesions with significant plaque burden 3
- Predilate the stenosis with appropriately sized balloon angioplasty (typically undersized by 0.5-1 mm relative to reference vessel) 1
4. Stent Selection and Deployment
- For atherosclerotic lesions, select an appropriate balloon-expandable stent (primary stenting is preferred over balloon angioplasty alone) 2
- Size the stent to match the reference vessel diameter
- For ostial lesions, position the stent to extend 1-2 mm into the aorta 1
- Deploy the stent at appropriate pressure to ensure full expansion
- Perform post-deployment balloon dilation if needed to maximize stent expansion 1
5. Final Assessment
- Perform completion angiography to confirm:
- Full lesion coverage
- <30% residual stenosis
- No flow-limiting dissection
- No distal embolization 1
- Measure post-intervention translesional pressure gradient (should be eliminated or significantly reduced) 1
- Ensure anatomic success with resolution of target vessel obstruction 1
6. Closure and Post-Procedure Care
- Remove sheath and achieve hemostasis
- Administer dual antiplatelet therapy (DAPT) for at least 1 month after stent implantation 1
- Monitor for contrast-induced nephropathy, particularly in patients with baseline renal insufficiency 1
Technical Considerations and Pitfalls
Stent Positioning: For ostial lesions, ensure the stent is flush with or projects 1-2 mm into the aorta to completely cover the lesion 1
Stent Selection: Use balloon-expandable stents for atherosclerotic RAS; reserve primary balloon angioplasty (with bailout stenting if needed) for fibromuscular dysplasia 2
Complications to Monitor:
Follow-up Protocol:
Renal artery stenting requires meticulous technique and careful patient selection to achieve optimal outcomes. The procedure has nearly uniform technical success when performed correctly, but long-term benefit depends on appropriate patient selection and avoiding complications 4.