Arterio-Venous fistula

How better is Arterio-Venous fistula for dialysis?

  • Arterio-Venous fistula or AV fistula is the surgical link connecting an artery and a vein and it is made by a vascular surgeon.
  • This connection usually happens in the arm, but if this can be even positioned in the leg.
  • In the case of extended or long-term dialysis, Arterio-Venous fistula is the most chosen method of vascular access.
  • Here, the human body will remain free from getting any synthetic material inserted.
  • This particular access satisfactorily helps in the hemodialysis treatment, by making the veins dilated and thus allowing enough blood to get carried through.
  • This method is much less sensitive towards clotting than most other dialysis options.
  • AV fistula also assures a speedy return to the established groove.

 

Why Arteriovenous fistula creation is used for hemodialysis and what are the various hurdles to face?

  • AV fistula is one of the permanent methods of vascular access that is obtainable for hemodialysis.
  • Being the ideal access for long-lasting dialysis, it is always reliable in the respect of any patient’s end-stage renal disease life design and their conditions for its creation.
  • Together with which, it is even compatible with the general objectives of care for the patients.
  • The creation of AV fistula needs enough arterial and venous anatomy.
  • For the satisfactory maturation of AV fistula, ample time interval is required.

Typical complications of Arterio-Venous fistula includes,

  • Thrombosis
  • Stenosis
  • Congestive heart failure
  • Ischemic neuropathy
  • Steal syndrome
  • Aneurysm
  • Infection

 

How to sustain the maintenance of hemodialysis Arterio-Venous fistula with the prevention of thrombosis?

The maintenance of the hemodialysis Arterio-Venous fistula should be perfect enough to avoid the related complications of AV fistula.

  • Cleanliness should be kept up by washing hands prior to and after touching the AV fistula and also by cleaning the area around the AV fistula.
  • Monitor the thrill in the AV fistula each day
  • Blood should not be taken out from the place where the AV fistula is located.
  • Take good care of the access.

Thrombosis can be prevented,

  • With the better safeguarding of forearm veins by evading the process of acquiring intravenous access (like intravenous cannula or blood sampling) in chronic kidney patients.
  • Beforehand creation of AV fistula, together with the utilization of natural veins can avert the possibility of thrombosis.
  • For restricting the occurrence of thrombosis, be careful with the existence of high venous pressure on dialysis.
  • The efficiency of the dialysis should be looked over.

 

What is referred to as the maturation of newly created hemodialysis Arterio-Venous fistula and what makes the process of evaluation imperative?

  • The revamping process Arterio-Venous fistula is called as maturation.
  • After the creation of Arterio-Venous fistula, the vascular remodeling will get activated with the hemodynamic forces that are acting on the blood vessels.
  • There should be a rise in the flow of blood for the ample conveyance to the dialysis machine.
  • For the insertion of cannula, the diameter of the blood vessel should be increased and it should also get thickened for the repeated cannulation.
  • The finishing line of this process is the Arterio-Venous fistula maturation.

Evaluation of the Arterio-Venous fistula is inevitable,

  • It is with the process of proper evaluation, the areas of stenosis in non-maturing fistulas can be spotted.
  • Without which, suitable considerations could not be given for the effective treatment against the complications and defects.
  • Additional evaluation can be done with duplex ultrasound or angiography.

 

What is meant by failure of the matured hemodialysis Arterio-Venous fistula?

  • When the fistulas are not functional or when they fail to work within the first three months, then it will be called as primary AV fistula failure.
  • When the failure happens, then the fistulas will stop getting developed but this can be corrected later.
  • The failure of the mature hemodialysis Arterio-Venous fistula usually happens as a result of stenosis.
  • It is commonly identified during the detection of stenosis.
  • It also happens when blood clotting occurs in the blood vessels, as this can restrict the dialysis treatment.
  • With the malfunctioning of the fistula, the amount of toxin and fluid expulsion will decrease.
  • It can be exposed by physical examinations, flow measurements, or duplex ultrasound scan.

How to clinically monitor and surveillance the mature hemodialysis arteriovenous fistula?

An Arteriovenous fistula (AVF) is a composition of the natural blood vessels and is a “gate of life” for the patients on hemodialysis and can provide rapid extracorporeal blood flow that is essential for hemodialysis; however, vascular stenosis is common and can direct to inadequate hemodialysis or AV fistula thrombosis if not realized and treated in a timely fashion.

Almost all the thrombosed mature AV fistulas have an underlying stenotic lesion. Although angiography is the most sensitive and detailed imaging modality to specify and characterize stenotic vascular lesions, it is expensive and invasive. For screening, noninvasive assessment is preferred to initially identify AV fistulas with a high likelihood of stenosis. AV fistulas with sufficiently abnormal screening tests would then undergo diagnostic angiography and if suggested, medication. Clinical monitoring and surveillance are presently used to screen for vascular stenotic lesions.

What is the approach to the patient expecting vascular access for chronic hemodialysis?

The purpose of chronic hemodialysis access is to give repeated access to the circulation with the least complications. Decisions encircling the initial choice of chronic hemodialysis access are complex and should be to maximize the likelihood of providing functional access within a proper period, minimizing during creation and access use, maximizing options for lifelong access, and taking considering patient preferences fundamental forms of chronic hemodialysis access are:

  • Arteriovenous (AV) fistulas
  • AV grafts
  • Hemodialysis catheters

Hemodialysis access is naturally attained using vessels in the upper extremities. The lower extremity is a less normally used initial access site. The upper chest can be tried when extremity sites have been exhausted. Ultimately, as a heroic measure, central venous catheters can be inserted into the inferior vena cava through translumbar or transhepatic routes.

How can you analyze the mature hemodialysis arteriovenous fistula?

Physical examination of the hemodialysis AV fistula is manageable and inexpensive and can frequently detect common problems corresponding to hemodialysis access.

It is recommended that physical examination be performed on all mature AV fistulas regularly and it must be analyzed at every hemodialysis treatment. Routine systematic physical examination of the fistula by the dialysis staff with each therapy may facilitate early detection of problems that are normally connected with mature fistula, thus avoiding missed medications and emergent situations.

Examination of the patient with hemodialysis access includes: 

  • Inspection of the fistula as well as analysis of the entire extremity.
  • The systematic trial of the mature AV fistula is to assess the integrity of the skin overlying the fistula, which should occur normally without erythema, focal masses, or focal swelling.
  • Cannulation sites must be well cured with minimal to no scabbing and no indication of inflammation.
  • There should not be any aneurysms (localized bulging zone) present. If an aneurysm is present, the skin overlying the bulging area should be detected for indication of depigmentation, thinning, ulceration, or spontaneous bleeding.

What is interpreted by a primary failure of the hemodialysis arteriovenous fistula?

Primary failure is interpreted as an arteriovenous fistula that has never been useful for dialysis or that fails within three months of use. The emphasis is mainly on the failure of maturation. It is a crucial problem; however, fistulas that fail to develop have a high incidence of correctable troubles, and once these problems are addressed, a high success rate can be expected.

Once an AV fistula is developed, it must formulate to the point that it is adequate in size and depth, allowing repeated successful cannulation, and can provide adequate blood flow to benefit the hemodialysis prescription. Whether an AV fistula will mature without additional intervention is most apparent at four to six weeks following creation. Early fistula evaluation stimulates the identification of areas of stenosis in non-maturing fistulas, which can then be safely and effectively treated with proper intervention. In several cases, a thorough physical examination of the access will point to the cause of the arrested maturation. If an abnormality is detected, further examination of the AV fistula should be attained as soon as possible, usually with duplex ultrasound or angiography.

 Are there risk factors for arteriovenous fistula failure during hemodialysis?

AVF is the preferred vascular access for hemodialysis. However, primary AVF dysfunction depicts an important barrier to the long-term success of HD therapy. Analysis of the end-stage kidney disease (ESKD) patient in preparation for the placement of hemodialysis access is extremely crucial. Proper patient choice improves the opportunity to place the access most appropriate for the individual patient. This examination should be detailed and exact.

Every predialysis and dialysis patient should have an individualized ESKD Life-Plan, which should begin in the predialysis period if possible, to maximize ESKD dialysis modality preferences and utilization for a particular patient’s foreseeable lifespan. In formulating this plan, risk factors having a potentially adverse effect on the success of dialysis access must be taken into consideration.

Many patients have more than one risk factor because they have numerous comorbidities. The dialysis patient population is among the sickest with a symptom burden similar to that of the cancer patient. Older patients portray the most quickly growing group of dialysis patients, and roughly one-half of ESKD patients over 75 years of age have three or more comorbidities.

This is directed primarily toward factors that generate a risk for failure of AV fistula development, it should be known that some of these factors also affect the risk to the patient’s well-being (life and limb).

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