The term ‘hemodialysis’ (HD) refers to the process of removing wastes and other fluids from the blood in a person with a faulty kidney. This function is ordinally performed by a healthy kidney. In this process, vascular process or hemodialysis access is used to reach the blood in hemodialysis. Three types of vascular access are as follows:
- Arteriovenous fistula
- AV graft
- HD catheter
Fistula vs Shunt
The main difference between fistula and shunt is that arteriovenous fistulas are made using blood vessels and the body’s tissues. On the other hand, a dialysis shunt is made using synthetic tubular material that creates a passage between a vein and an artery. The risk of infection is much less in arteriovenous fistulas than in a shunt.
An arteriovenous (AV) fistula is surgically made by connecting an artery with a vein. It can be placed in the upper arm, wrist, or forearm. It helps in providing vascular access to the blood vessels by the creation of extra pressure through an increased blood flow into the veins.
A shunt is a small channel artificially created and placed in the brain via surgery. Its main function is to allow the fluid to move freely from one part of the body to another. It comprises a synthetic tube placed under the skin to connect the artery with the vein. It offers needle placement access for dialysis.
Comparison Table Between Fistula and Shunt
|Parameters of Comparison||Fistula||Shunt|
|Definition||It is an abnormal passageway an artery and a vein.||It is a hollow synthetic tube placed in the brain to allow the cerebrospinal liquid to flow to other parts.|
|Types||3 most common types of arteriovenous fistula are radiocephalic fistula, brachiocephalic fistula, and brachial artery-to-transpose basilic vein fistula||There are five types of a shunt.|
|Components||These do not contain any artificial components.||It has 3 components created artificially using synthetic tubular material and flexible silicone.|
|Uses||An arteriovenous fistula is used in hemodialysis||It is used in the treatment of hydrocephalus and various other diseases|
|Infection risk||Less||Very high|
What is Fistula?
The arteriovenous fistula connects an artery and a vein. Ordinarily, blood flows from arteries to capillaries and finally reaches the veins. In the presence of arteriovenous fistulas, blood directly flows to veins from arteries, skipping various capillaries in the process. It is usually found in the legs, although it can develop in any part of the body.
Causes of arteriovenous fistulas are as follows:
- Congenital i.e., being born with it: Sometimes, babies are born with arteriovenous fistula
- Skin piercing injuries: This may occur in a piercing injury such as a stab wound or gunshot on a body part where artery and veins run side by side.
- Dialysis-related surgery: To ease the process of dialysis, an arteriovenous fistula is created surgically in the forearm to treat late-kidney failure.
- It can also be created through various genetic conditions.
When it is created through dialysis-related surgery, the doctor regularly monitors the fistula. However, if it is left untreated for long in other cases, it may cause heart failure, blood clots, leg pain, and bleeding in the gastrointestinal system.
It needs to be properly cared for. Before being used for dialysis, a surgically made fistula has to mature for 4-6 weeks or more, There are certain risk factors too that lead to the creation of an arteriovenous fistula.
What is Shunt?
A shunt is an empty tube placed surgically in the brain. This allows the cerebrospinal fluid to flow to another part of the body where it can easily be reabsorbed. It helps to deal with hydrocephalus by addressing brain pressure and relieving the symptoms of hydrocephalus such as mild dementia, gait difficulty, and lack of bladder control.
Different kinds of shunts are as follows:
- Lumboperitoneal shunt
- Ventriculoatrial shunt
- Ventriculopleural shunt
- Ventriculoperitoneal shunt
- Ventriculogallbladder shunt
Each of the shunts drains excess cerebrospinal fluid to different parts of the body respectively. Various complications such as over-draining, seizures, abdominal complications, bowel perforation, pseudocyst formation, etc.
The surgical procedure requires about an hour and then the patient is placed under surveillance for 24 hours. Follow-up visits are necessary to ensure proper functioning. Rehabilitation strategies such as physical therapy, occupational therapy, etc may also be advised to resolve symptoms.
Various risks and complications include blockage, infection at the wound, or shunt malfunction. Shunt malfunction includes over-or-under-drainage. Infection at the wound may cause symptoms such as low-grade fever, redness along the path of the shunt, soreness of the neck, etc.
It can also be used in the treatment of blurry vision, idiopathic intracranial hypertension, Chiari malformation, hemorrhagic stroke, shunt infection, etc.
Main Differences Between Fistula and Shunt
- Fistula acts as a passageway connecting an artery and a vein whereas a shunt is placed in the brain to allow the cerebrospinal liquid to flow to other parts of the body.
- There are three common types of fistula whereas there are five types of shunts.
- AV fistula does not comprise any artificial component whereas shunt does.
- The main use of an arteriovenous fistula is in hemodialysis whereas a shunt is used to treat hydrocephalus and various other diseases.
- AV fistula surgery is less expensive than shunt surgery.
- Infect risk involved in a fistula is much less compared to a shunt.
A fistula and a shunt are quite different from one another in all aspects. They differ in their use, price, infection risk, and other things. Fistula surgery is performed to get vascular access in hemodialysis whereas shunt surgery is performed primarily to treat hydrocephalus.
In surgery too, a fistula can be placed in any part of the body whereas a shunt can only be placed inside the brain. Both require great care and can lead to complications, thus frequent follow-ups with the doctor are essential.