Kidney failure necessitates dialysis, a life-sustaining treatment that filters waste and excess fluid from the blood. Effective dialysis requires reliable vascular access to the bloodstream. This access allows blood to flow to and from the dialysis machine for cleansing. Maintaining this site is important for continuous treatment.
Understanding Dialysis Access
There are three types of vascular access used for hemodialysis. An arteriovenous (AV) fistula is created surgically by connecting an artery directly to a vein, typically in the arm. This connection causes the vein to enlarge and strengthen, allowing for the high blood flow rates required for dialysis.
An AV graft involves connecting an artery and a vein using a synthetic tube, often used when a patient’s veins are not suitable for a fistula. It provides a quicker option for dialysis than a fistula, which needs time to mature. A central venous catheter (CVC) is a flexible, Y-shaped tube inserted into a large vein, usually in the neck, chest, or groin, and is often used for immediate or temporary dialysis.
Purpose of Stents in Dialysis
Stents are used in dialysis to maintain or restore the patency of blood vessels, especially when narrowing or blockages occur within the dialysis access site or in the central veins that drain blood from the access. Over time, repeated use and high blood flow through dialysis access can lead to vein thickening and narrowing, a condition called stenosis, or even blood clots. These issues impede adequate blood flow, making effective dialysis challenging or impossible.
Stents act as internal scaffolds, holding the vessel open to ensure consistent and sufficient blood flow for dialysis. They are deployed when balloon angioplasty alone, a procedure to widen narrowed vessels, is not enough to keep the access open. By preventing the vessel from collapsing or re-narrowing, stents prolong the life of the vascular access, reducing the need for frequent interventions and ensuring patients can continue their scheduled dialysis treatments.
Stent Placement and Function
Stent placement for dialysis access is a minimally invasive procedure performed by an interventional radiologist or nephrologist. After numbing the access site with a local anesthetic, a small incision or puncture is made. A thin catheter is guided through the blood vessel to the narrowed or blocked area using imaging guidance, such as fluoroscopy, which provides real-time X-ray images.
At the narrowing, a balloon at the catheter’s tip may be inflated to widen the vessel, a process called angioplasty. If angioplasty alone is insufficient, a small wire mesh tube, the stent, is then deployed and expanded to hold the vessel open. Stents remain permanently in place, providing continuous support to the vessel wall. Types include bare-metal stents, made from materials like stainless steel or nitinol, and covered stents, which have a synthetic material coating, such as polytetrafluoroethylene (PTFE).
Living with a Dialysis Stent
After stent placement, patients can return home the same day, with monitoring for complications. Post-procedure care involves observing the access site for signs of infection, such as redness or swelling, or bleeding. Patients are advised to avoid heavy lifting or strenuous exercise for about a day following the procedure.
Regular follow-up appointments with the healthcare team are important to monitor the stent’s function and the overall health of the dialysis access. Complications such as re-stenosis (re-narrowing of the vessel within the stent), thrombosis (blood clot formation), or infection can occur. Patients should be aware of changes in their access, such as a loss of the characteristic “thrill” or vibration, which can indicate a problem and should prompt immediate medical attention.