Arteriovenous Fistula 動靜脈瘻管
◼ 1.1 About arteriovenous fistula
Arteriovenous fistula (AVF) surgery is a surgical procedure that connects an artery and an adjacent vein to create an arteriovenous fistula, which serves as an artificial blood vessel for hemodialysis treatment.
There are two types of arteriovenous fistula:
Autologous Arteriovenous Fistula (AVF)
- The AVF utilizes the patient’s own artery and vein, which are directly sewn together during the surgery.
- The procedure can be performed under local or general anesthesia. Before the surgery, the doctor will use ultrasound to select a suitable superficial vein in the upper limb and then directly connect the artery and vein at the wrist or elbow.
- The surgery increases blood flow in the vein, thereby increasing the venous pressure, causing the vein to thicken and enlarge, forming an arteriovenous fistula.
- It takes six to eight weeks for the vein to mature and be suitable for hemodialysis.
- Surgeons typically choose the patient’s left hand for the fistula surgery as it has less impact on the patient’s daily activities.
- Additionally, the ideal location for the fistula surgery is farther away from the heart to reduce the burden on the heart from increased blood flow in the fistula.
Arteriovenous Graft (AVG)
- The purpose of this surgery is to create an artificial graft connecting an artery and a vein to establish an artificial conduit for hemodialysis.
- When the patient’s arteries and veins are too small or have significant sclerosis, the success rate of autologous AVF may be low, necessitating the use of an implanted artificial graft.
- Surgeons use a polytetrafluoroethylene (PTFE) graft to connect the artery and vein, with one end anastomosed to the artery and the other end to the vein, creating an artificial blood vessel conduit.
- After the surgery, doctors usually recommend waiting at least two to three weeks before using the artificial graft.
- Autologous AVF is preferred by doctors whenever possible, but if the patient does not have suitable native vessels, an artificial graft (AVG) is used.
- In cases of acute kidney failure where autologous AVF cannot be awaited or when temporary hemodialysis is required for patients undergoing peritoneal dialysis or kidney transplantation, an AVG may be used.
◼ 1.2 Application of arteriovenous fistula
End-stage renal failure is a type of long-term chronic disease where patients require long-term hemodialysis treatment to maintain limited kidney function. Hemodialysis is the most important treatment method for patients with renal failure. During hemodialysis, blood is drained from the body through a catheter connected to the blood vessels, sent to the hemodialysis machine, and purified by an artificial kidney to remove waste products and excess fluid. The purified blood is then returned to the body through the catheter.
To control blood pressure and maintain the balance of electrolytes in the body, patients must follow a prescribed schedule and undergo hemodialysis two to three times a week, with each session lasting four hours or more. Generally, two hemodialysis treatments per week are sufficient for most patients, but some patients require three sessions per week. Additionally, if a kidney disease patient also has heart failure, the heart may not tolerate excessive fluid accumulation, necessitating three hemodialysis sessions per week.
However, before undergoing long-term hemodialysis, most patients need to undergo arteriovenous fistula surgery to allow smooth blood flow out of the body to the hemodialysis machine for processing and return to the body. Each hemodialysis session requires healthcare personnel to puncture the fistula for immediate hemodialysis treatment, prolonging the patient’s life.
