In another article we briefly discussed thrombolysis of clotted hemodialysis access. We also noted that it is estimated that 85% of graft and fistula failures are predictable, treatable and hence preventable, yet sometimes they just clot, no matter how careful you are.

What we didn't discuss is that no matter how careful you are, if you are in this field for long you will inevitably get a phone call telling you that the arm graft you declotted last week - the one that looked so good, the one you were so proud of - is clotted again. You will declot the graft again, look for overlooked problems, and hope to find a way to stop seeing that particular patient so often.

I tell my patients I want them to be just like "family", which in my world means I prefer to see them only once a year. To accomplish that, I need to find ways to make my interventions more enduring.

The use of stents in repairing, restoring or normalizing hemodialysis access is controversial. In 1997, the DOQI committee found that the unassisted patency of stents in hemodialysis access was no better than venoplasty except in cases of elastic stenosis and suggested that stents be limited to surgically inaccessible lesions or where there is a contraindication to surgery (Guideline 19).

Since that time, stent technology has evolved, with dacron-covered stents, PTFE-covered stents, and drug eluting stents either now or soon to be available, and more extensive experience with the use of stents in hemodialysis access. There is now a general consensus that stents are indicated when there is rebound stenosis with more than 30% residual stenosis after balloon dilation, where there is restenosis within a short time period (one to three months) or where there is rupture of a vessel during dilation.

Stents are now being used in more innovative ways - patching pseudoaneurysms in grafts, providing a durable fix in venous anastomotic stenosis, and lining recannalized central venous occlusions with a PTFE-covered channel.

Results are mixed, and depend on many factors. My own experience includes patients whose recurring venous anastomotic stenoses were PTFE-stented up to several years ago, and when re-examined have been found to be completely clean in the stented areas. Central venous occlusions have also been effectively managed, with preservation of upper-extremity options for dialysis that would otherwise have been lost.

Dacron-covered and bare-wire stents have not faired so well and have required more frequent intervention, or have failed. Nevertheless, it is clear that we have managed to keep many grafts and fistulas functioning well beyond the point that they would have been abandoned or returned to the operating room.

Stents are another tool in the armamentarium of the vascular access provider, and as such can be used wisely in selected circumstances to achieve results impossible otherwise. The injudicious or profligate use of stents will not improve results, and may raise costs.