Dialysis Access Procedures

A Vascular Access procedure involves a procedure which can be utilized for hemodialysis: 

There are three types of vascular access:

• Arteriovenous (AV) fistula
• Arteriovenous (AV) graft
• Central venous catheter (CVC)

These accesses can also be categorised as “Temporary” & “Permanent” Vascular Accesses.

Temporary Access Types

• Internal Jugular Access (a type of CVC)
• Femoral Access (a type of CVC)
• Perma Catheter (a type of tunneled CVC): which has less blockage & infection rates and is suitable for longer duration of dialysis.

Permanent Access Types

• Arteriovenous (AV) fistula
• Arteriovenous (AV) graft

The “Rule of 6s” describes an easy way to evaluate the maturity of a recently-placed arteriovenous fistula for dialysis access in a dialysis patient. The Rules of 6 further explained as flow volume >600 mL/min, vein diameter >6 mm, vein depth <6 mm 

The Rule of 6s is as follows:

6 weeks after the AV fistula has been placed in dialysis patient the fistula should:

1. be able to support a blood flow of 600 ml/min.
2. be at a maximum of 6mm from the surface.
3. have a diameter greater than 6mm.

Failure to achieve the above rules of 6 goals warrants a further investigation, usually in collaboration with the surgeon who placed the fistula, into why the fistula did not mature.  Ideally, the existing fistula can still be encouraged or modified to eventually achieve maturity; if not, a new access site can be attempted.  

To provide comprehensive treatment to dialysis patients, physicians must establish a connection between the dialysis machine and the bloodstream of the patient. Dialysis Access Surgery is a surgical technique that creates the vascular access through which a needle can be inserted for hemodialysis.

Arteriovenous fistulas (AVFs) is considered the gold standard and recommended by many clinical guidelines as the vascular access of choice in Hemodialysis patients. The AV Fistula is considered the “Gold Standard” access because it has a lower risk of infection than other access types, lower risk of forming clots than other access types, allows for greater blood flow, lasts longer than the other access types, it lasts longer than the other access methods, it can last many years. Hence AV fistula is the golden standard of dialysis accesses.

There are 3 different types of dialysis access for hemodialysis. They are called a fistula, a graft, and a catheter. Further it is explained as Arteriovenous (AV) fistula, Graft Access and complex Vein transposition ( bypass) procedures.

• AV Fistula is an access site formed by the joining of an adjacent vein and an artery at your wrist or elbow. This is a simpler surgery performed under local anesthesia. 
• Graft is an access site formed by a piece of soft tubing ( artificial graft) that connects a vein and artery in your arm. It is only recommended for patients who do not have suitable veins. 
• Vein transposition surgery: these are complex surgeries done under regional anesthesia in which longer segment of deeply situated vein is brought in a superficial plane for easier dialysis. Our team has a very high level of experience and expertise in these complex dialysis access procedures. 

An Artery to Vein or AV fistula is the best choice for hemodialysis. It is preferred because it usually lasts longer and has low rate of complication or problems like clotting and infections. The arteriovenous fistula is considered to be a preferred type of vein access for dialysis as it provides a good blood flow and lasts longer than other types of access for dialysis. The role of basilic vein transposition surgery is also very important in patients who do not have veins suitable for a fistula surgery.

The “rule of 7’s” is a basic approach where the potassium level of the patient plus the dialysate potassium concentration should equal approximately 7.

A well functioning vascular access is a mainstay to perform an efficient hemodialysis procedure. Commonly cephalic vein at wrist ,forearm or elbow is used for AV fistula. Basilic vein is used for transposition surgery when cephalic vein is not suitable or blocked.

Remember that a fistula or basilic vein is the lifeline for a proper dialysis. If blocked, it is advisable to consult Vascular surgeon who can reopen the blocked veins by angioplasty interventions. Sometimes, it may be advisable to undergo a fresh new fistula or basilic vein  bypass.

Some common yet often missed warning signs of access dysfunction include

1. Slow flow or needling difficulties 
2. Clots during dialysis
3. Prolonged Bleeding after dialysis is over 
4. Aneurysmal swelling 
5. Episodes of hematoma or bruising 
6. High venous pressures or pain during dialysis.
7. Edema or swelling of entire hand

If you notice any of these problems, it is advisable to consult our vascular surgeon at the earliest. Most of these problems can be evaluated and corrected well if detected early.

A properly trained Vascular & Endovascular Surgeon who is an expert in the following may be most suitable to provide a suitable dialysis access

1. Doppler mapping of vein before and after surgery, 
2. Can perform fistula, vein transposition or graft surgeries
3. Can treat fistula complications
4. Can perform fistula angiography and angioplasty for fistula salvage ( to save failing AV fistula)