Hemodialysis is a treatment that purifies the blood of a person whose kidneys have failed. This treatment involves a machine used to route a patient’s blood through a filter, called a dialyzer, outside the body.
Before hemodialysis can be done, a connection must be made to the blood inside the blood vessels. A hemodialysis access, or vascular access, is a way to reach the blood for hemodialysis. The access allows blood to travel through soft tubes to the dialysis machine, where waste products and extra fluid are filtered out. The machine then returns the filtered blood to the body through a separate tube.
The two types of vascular access for patients on long-term hemodialysis include:
- Arteriovenous (AV) fistula
- Arteriovenous (AV) graft
For patients undergoing short-term hemodialysis or those who require emergency hemodialysis, a venous catheter is used for vascular access.
Creation of Arteriovenous Fistula
An arteriovenous (AV) fistula is the connection of an artery to a vein. This creates a large blood vessel that provides excellent blood flow. An AV fistula is typically placed in the forearm or upper arm of a patient by a vascular surgeon. An AV fistula is considered the best choice for hemodialysis because it lasts longer than other types of access and is less likely to become infected or to develop blood clots.
An AV fistula requires 2-3 months to mature before it can be safely used for hemodialysis. During that time, patients might undergo a fistulogram, an X-ray procedure to look at the blood flow and check for blood clots or other blockages in the fistula that may interfere with dialysis. A radiologist inserts small catheters into the fistula and injects special dye that can be seen on X-rays.
Creation of Arteriovenous Graft
An arteriovenous (AV) graft, the second choice for hemodialysis access, uses an artificial tube inserted by a vascular surgeon between a vein and a nearby artery. The graft is typically put inside the bend of the arm or in the upper arm and is generally ready for hemodialysis 2-3 weeks after the surgery. An AV graft has a higher risk of infection and clotting than an AV fistula.
Vascular Access Complications
Both types of vascular access — AV fistula and AV graft — can cause problems that require further treatment or surgery. The most common problems include access infection, low blood flow due to blood clotting in the access, "Steal Syndrome" and aneurysms.
Evaluation Prior to Access
Patients undergoing dialysis access creation may experience a workup that includes diagnostic vascular ultrasound imaging, venograms, angiograms, fistulogram or MRI studies.
Hemodialysis Access Through U-M Vascular Surgery
The University of Michigan Vascular Surgery department has skilled surgeons, board-certified for the treatment of dialysis access. We are able to provide comprehensive care for patients in need of dialysis access creation or the management of complications 24/7. New patients for hemodialysis access are seen at the Vascular Surgery Clinic at the Brighton Center for Specialty Care.
Make an Appointment
To make an appointment call the University of Michigan Frankel Cardiovascular Center toll-free at 888-287-1082 or email us at CVCCallCtr@med.umich.edu. Visit our Make an Appointment page for more information about what to expect when you call us.