Vascular access for hemodialysis - Basic concepts

What is vascular access?

The vascular access is a hemodialysis patient’s "life line" and constitutes hemodialysis feasible as a cure. 

It is the "connection" that provides a continuous and uninterrupted blood flow from the patient to the hemodialysis machine and the patient then receives it back filtered. Without blood supply, hemodialysis could not be possible.

  • What types of vascular access are there?
  • There are three types of vascular access suitable for hemodialysis:
  • The arteriovenous fistula, made by a vascular surgeon by connecting an artery with a vein, from the patient's existing arterial and venous network without the insertion of any synthetic material. 
  • The arteriovenous graft, which is a synthetic tube, consisting of soft special plastic or other material, and the vascular surgeon places it under the skin to connect an artery wih a vein when it is not feasible to create the fistula. 
  • The venous catheter, which is a tube placed either at the base of the throat (ideally) or near the foot, usually only for short - term hemodialysis. When the arteriovenous fistula or arteriovenous graft matures, the catheter is removed.

The "permanent" hemodialysis catheter is a catheter with subcutaneous tunnel for long - term use. It is installed when any other solutions can be applied (fistula or graft). Permanent central venous catheters are most commonly placed in the anterior chest wall and are joined through a subcutaneous tunnel with the internal jugular vein, right or left.

Both in fistula and graft, the connection between the artery and the vein leads to an increase in blood flow through the vein. In response, the vein grows and strengthens its walls. This allows even more blood to pass through the vein and allows for an effective dialysis. In the following weeks after surgery, the fistula begins to mature.

  • At which part of the body is the fistula developed?

The access (fistula or graft) is usually created in the hand, or rarely in the foot (thigh). Depending on the quality of the artery and vein, the vascular surgeon will try to create the fistula on the forearm (usually on the wrist) of the opposite hand from the dominant hand. For example, if you are left-handed, the doctor will create access to your right hand if possible. During surgery, the doctor will try to attach a large vein under the skin (surface) to a neighboring artery. If it is not possible to create a fistula because the central vein is too small or coagulated, the doctor may place a graft that is usually synthetic (plastic).

  • What does the procedure of creating access to hemodialysis entail?

The surgical operation is performed in the hospital. With local anesthesia, the vascular surgeon creates the fistula or places the graft. The duration of hospitalization is usually short, approx. 1-2 days.

  • What is "the best" vascular access?

Arteriovenous communication (fistula) which is created with the patient's blood vessels.

  • What are the benefits of the arteriovenous communication?
  • The arteriovenous communication is the preferred type of dialysis access because:
  • • it uses the patient's own blood vessels
  • • it does not require the permanent placement of foreign materials such as those required to create a dialysis or dialysis catheter.
  • • it is less prone to infection than a catheter or a synthetic graft
  • • it is less likely than the graft to have problems with its coagulation and accessibility 
  • • it provides good blood flow

• it provides the opportunity for repeated punctures and prolonged life

  • When should arteriovenous communication be performed?

It must be performed when the patient reaches stage 4 CKD, ie when the patient’s Glomerular Filtration Rate (GFR) is about 25 ml / min or when his creatinine reaches more than 4 or approximately 6 months before the estimated onset of hemodialysis treatments.

  • Do I have to exercise the hand of the arteriovenous communication?

Exercising the hand of the arteriovenous communication helps to improve the muscle tone and make the veins firmer and therefore the placement of the needle becomes easier. The most common exercise is to keep a soft ball in the hand of the arteriovenous communication and hang the hand to the side of the body while tightening (counting to 5) and release the ball slowly several times for 5 minutes. Repeat the exercise 3-4 times daily.

  • When will the vascular access be ready?

For the arteriovenous fistula, it usually takes 30 days from the day it is created to being suitable for use, but it may take longer (up to 6 months). An arteriovenous graft positioned between an artery and a vein can usually be used for dialysis within 2-6 weeks (lately there are newer direct fistula punctures). The venous catheter is readily available. Once mature, a fistula should be large and strong enough for nurses to be able to insert hemodialysis needles easily. If it fails to mature within a reasonable time, you may need new fistulas. The staff of the Hemodialysis Unit is trained to estimate when an arteriovenous communication is ready for use and also decide when it will be used.

   

Pic.1 Permanent" hemodialysis catheter at the right jugular vein

Pic.2 Placement of an arteriovenous graft between an artery and a blood vessel  

Pic. 3 The arteriovenous communication (fistula)

  • Mesogeios Dialysis Centers Group Scientific Team
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  • Bibliography 
  • 1.  http://www.fistulafirst.org/
  • 2.  KDOQI : Clinical Practice Guidelines for vascular access, update 2006
  • 3.  Arteriovenous anastomosis in hemodialysis patients. A systematic review. Greek Nephrology 2011; 23 (4): 252-267
  • 4. Allon M, Radeva M, Bailey J et al HEMO Study Group. The spectrum of infectionrelated morbidity in hospitalized hemodialysis patients. Nephrol Dial Transpant 2005; 20: 1180-1186
  • 5.  European Best Practice Guidelines for Hemodialysis  NDT,Volume 17, Issue suppl_7
  • 6. Thomas M, Nesbitt C, Ghouri M, Hansrani M. Maintenance of Hemodialysis Vascular Access and Prevention of Access Dysfunction: A Review. Ann Vasc Surg. 2017 Aug;43:318-327. doi: 10.1016/j.avsg.2017.02.014. Epub 2017 May 4. Review.
  • 7. Jemcov TK, Van Biesen W. Optimal timing for vascular access creation. J Vasc Access. 2017 Mar 6;18(Suppl. 1):29-33. doi: 10.5301/jva.5000685. Epub 2017 Mar 5. Review. PubMed PMID: 28297054.
  • 8.  Masengu A, Hanko J. Patient factors and haemodialysis arteriovenous fistula outcomes. J Vasc Access. 2017 Mar 6;18(Suppl. 1):19-23. doi: 10.5301/jva.5000665. Epub 2017 Mar 5. Review. PubMed PMID: 28297052.

9.  Scher LA, Shariff S. Strategies for Hemodialysis Access: A Vascular Surgeon's Perspective. Tech Vasc Interv Radiol. 2017 Mar;20(1):14-19. doi: 10.1053/j.tvir.2016.11.002. Epub 2016 Nov 29. Review. PubMed PMID: 28279404.

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