**5.7 Stent placement**

Several challenges must be faced by resistant or recurrent stenosis throughout the access circuit in terms of providing optimal hemodialysis treatment. Those stenoses can be successfully treated by endovascular stent placement, although it usually requires multiple procedures to maintain patency.

Indeed, bare metal stents and covered stents have emerged as a potential additional therapeutic intervention in vascular access dysfunction. However, results are not encouraging. For example, bare stents are seldom used due to a high incidence of in-stent stenosis, and covered stents also have problems.

There are three mostly accepted indications for stent deployment: (i) a stenotic lesion that recurs within a 3-month period after initially successful balloon angioplasty in a patient with *exhausted VA sites*, (ii) a stenotic lesion with high elastic recoil (usually in central veins), and (iii) rupture of an outflow vein after balloon angioplasty that cannot be handled using more conventional actions (balloon tamponade). Other special conditions where a stent implantation should be considered include (i) venous outflow stenosis, (ii) pseudo-aneurysms, and (iii) cephalic arch stenosis.

We must take special care not to occlude important collateral veins with implanted stent, namely, the homolateral internal jugular vein, always required for future central vein catheters.

There are several reported complications associated with stent placement, such as stent migration, or stent fracture, which is usually seen on control angiograms. Infection is also a significant complication with potentially tragic outcomes. It should be noted that the combination of the immune-compromised status of patients with ESRD and repetitive cannulations for dialysis treatments is likely factors leading to infection. One unique complication is stent struts protrusion, which results from placing stents in cannulation sites [62]. Damage of the metal part of the stents (struts) can result from repetitive cannulation.

The high cost of stents has to be taken into account, raising the question whether the benefits obtained by placing stents at stenotic lesions outweigh the costs associated with such treatment [9]. One should reflect if the option of creating a secondary AVF should be considered as an alternative treatment for placing a stent (**Figure 4**).
