Dialysis AV fistulas and grafts are surgical procedures used to create access for hemodialysis in patients with chronic kidney disease. Hemodialysis is a treatment that filters waste and excess fluid from the blood using a machine, and it requires a reliable access point to the bloodstream.
An AV fistula is created by surgically connecting an artery and a vein in the arm, using the patient’s own blood vessels. This creates a large, high-flow access point for hemodialysis. An AV fistula typically takes several weeks to mature and become usable for dialysis, but it is considered the best long-term option because it is durable and has a lower risk of complications.
An AV graft is similar to an AV fistula, but instead of using the patient’s own blood vessels, a synthetic tube is grafted onto the arm to create the access point for hemodialysis. An AV graft is easier to use for dialysis immediately after surgery, but it has a higher risk of complications such as infection and blockage.
In general, AV fistulas are considered the better option because they have a lower risk of complications and are more durable. However, not all patients are able to have an AV fistula, and in some cases an AV graft may be the only option. Your doctor will be able to recommend the best option for you based on your individual circumstances.
AV Fistulas (AVF) –
these are native vessel connections
General consensus is that these are preferred over grafts but 65% of patients are not surgical candidates… Their veins are too small, atherosclerosis,or central venous occlusion.
AVG DURABILITY = 3 years, intervention extends up to 7 years.
Signs of fistula failure = arm swelling, elevated central venous pressure at dialysis, decreased thrill
SITES
Forearm = Radiocephalic (Brescia-Cemino) – 70%
Elbow/Arm = Brachiocephalic or brachiobasilic – 30%
BENEFITS
Better long-term patency
Lower rate of thrombosis o Lower rate of infection
PROBLEMS
Fistula takes, on average, 10 weeks to reach maturation for use.
Stenosis of the outflow vein (just beyond the anastomosis) B A Radiocephalic AVF with minor stenosis at anastomosis
(A) and major stenosis 2 cm into the outflow vein (B). AV Grafts
(AVG) – these are artificial conduits Most common graft is a 6-mm PTFE (synthetic) graft
AVG DURABILITY = 1-2 years
intervention extends up to 3-5 years
SITES o Upper extremity: Brachiobasilic, Radiocephliac, Axillary-axillary, Axillary-contralateral axillary (“necklace”), etc. o Lower extremity: Femoral-saphenous, femoral-femoral
BENEFITS o Ready for use sooner, in 4-6 weeks o Can be placed in any number of locations
PROBLEMS o **Stenosis at the venous anastomosis – 90% of cases secondary to intimal hyperplasia. o Less common stenosis occur inside the graft and in the outflow vein. o Thrombosis – o Infection – this is a contraindication to endovascular intervention.
Treatment of graft thrombosis generally involves placing an angiocath and slowly infusing 2 mg tPA and waiting. There are also mechanical methods of thrombectomy.
Frequently Asked Questions
What is the difference between a dialysis fistula and a graft?
A dialysis fistula, or AV fistula, is created by connecting an artery and a vein using the patient’s own blood vessels. It takes time to mature but is durable and has a lower risk of complications. An AV graft, on the other hand, uses a synthetic tube to connect the artery and vein. It is ready to use sooner but has a higher risk of complications like infection and blockage.
Why is an AV fistula preferred over an AV graft?
An AV fistula is generally preferred because it has better long-term patency, meaning it stays open longer and is more durable. It also has a lower rate of complications such as thrombosis (blood clots) and infection compared to an AV graft. However, it takes longer to mature before it can be used for dialysis.
How long does it take for a dialysis fistula to mature?
A dialysis fistula typically takes about 10 weeks to mature before it can be used for hemodialysis. This maturation period allows the fistula to develop the necessary size and strength to handle the blood flow required for dialysis.
What are the signs of a failing dialysis fistula?
Signs of a failing dialysis fistula can include swelling in the arm, elevated central venous pressure at dialysis sessions, and a decreased thrill—a vibration felt over the fistula. It's important to monitor these signs and consult a healthcare provider if they appear.
What are the common complications of an AV graft?
Common complications of an AV graft include stenosis at the venous anastomosis, thrombosis (blockage due to blood clots), and infection. Stenosis occurs in about 90% of cases due to intimal hyperplasia, which is a thickening of the vessel wall. These complications may require interventions to address them.
Can anyone have an AV fistula for dialysis?
Not all patients are suitable candidates for an AV fistula. Factors such as small veins, atherosclerosis (hardening of the arteries), or central venous occlusion may prevent the creation of a fistula. In such cases, an AV graft may be the only option.
Where are dialysis fistulas and grafts typically placed?
Dialysis fistulas and grafts are commonly placed in the upper extremities. Fistulas are often created in the forearm or the elbow/arm areas, while grafts can be placed in various locations including the upper and lower extremities, such as the brachiobasilic, radiocephalic, and femoral areas.
How is a thrombosed dialysis graft treated?
A thrombosed dialysis graft is typically treated by placing an angiocatheter and slowly infusing tissue plasminogen activator (tPA), a medication that helps dissolve blood clots. Mechanical methods of thrombectomy, which physically remove the clot, may also be used in some cases.
Need a Medical Expert?
Our network of board-certified specialists provides expert witness services for medical-legal cases.
