Can peripheral artery stenting cause loss of collateral (collateral) circulation?

Peripheral Artery Stenting and Collateral Loss

Covered stents can inadvertently occlude or "jail" important collateral vessels, which is a recognized complication that must be carefully considered when planning endovascular intervention. 1

Mechanism of Collateral Loss

The primary concern with peripheral artery stenting relates specifically to covered stents, which can physically obstruct collateral vessels at their origins:

• The covered component of stents can inadvertently cover or "jail" important collaterals, particularly when placed in central venous locations or major arterial segments 1
• This mechanical obstruction occurs when the stent graft material physically blocks the ostia of collateral vessels that branch from the main arterial trunk
• Bare metal stents pose less risk for collateral loss compared to covered stents, as the open mesh design typically allows collateral flow through the stent interstices 1

Clinical Significance of Collaterals

Collateral circulation is critically important for tissue preservation and clinical outcomes, making their preservation a key consideration:

• In the absence of direct perfusion, tissue viability depends entirely on collateral flow 1
• Patients with robust collateral circulation have smaller infarct volumes and better clinical presentations compared to those without collaterals 1
• The presence and adequacy of collaterals directly influences whether patients benefit from revascularization procedures - patients without collaterals may not benefit from intervention, while those with collaterals show improved outcomes 1
• After arteriovenous access construction, collateral development typically occurs within 2-6 weeks and can maintain function even with proximal stenosis or occlusion 1

Anatomic Considerations

The risk of collateral loss varies by location and stent type:

• Covered stents should be used with extreme caution or avoided altogether in regions where critical collaterals exist, such as the thoracic outlet where extrinsic compression can also cause stent fracture 1
• In superficial femoral artery occlusion, the deep femoral artery provides crucial collateral circulation to reconstitute the popliteal artery, and isolated superficial femoral artery occlusion rarely causes limb-threatening ischemia due to these collaterals 1
• Popliteal and tibial arterial segments have limited collateral pathways, making preservation of any existing collaterals particularly important 1

Clinical Decision-Making Algorithm

A careful tiered approach should be followed to minimize collateral loss:

1. Start with balloon angioplasty alone for initial treatment of stenotic lesions 1
2. Progress to bare metal stents only for angioplasty failures or recurrent stenosis 1
3. Reserve covered stents as a last resort after failure of both balloon angioplasty and bare metal stents, and only in the context of the patient's overall vascular access plan 1
4. Pre-procedural angiography must include both arterial and venous phases to fully evaluate collateral pathways and plan stent placement to avoid critical collateral origins 1

Common Pitfalls to Avoid

• Never place covered stents without careful angiographic assessment of collateral vessels - the covered component can permanently occlude collateral origins 1
• Do not assume that restoring main vessel patency will compensate for lost collaterals - in some anatomic locations (such as lenticulostriate arteries supplying basal ganglia), collaterals cannot be recruited from other territories 1
• Avoid stent placement over important venous tributaries like the internal jugular vein, which can serve as critical collateral drainage 1
• Recognize that 20-30% of patients have persistent symptoms despite patent stents, which may reflect inadequate collateral preservation or development 2, 3

Post-Stenting Surveillance

Monitor for signs of inadequate collateral circulation:

• Persistent extremity edema beyond 2 weeks post-procedure suggests inadequate venous collateral drainage 1, 2
• Development of new ischemic symptoms despite patent stent may indicate collateral loss 3
• Duplex ultrasound at 1 month, 6 months, and annually can detect both in-stent restenosis and assess collateral flow patterns 3