Skip to main content
Dialysis.sc

Clinical reference

Vascular access management

Access is the lifeline of haemodialysis and the largest single source of procedure burden and admission in the dialysis population. It is also the area where the guideline moved furthest in the last decade, and where practice has moved least.

Fistula-first, and why the slogan was retired

The classical case for the arteriovenous fistula is real: better long-term patency, lower infection rate, lower intervention rate, better blood flow, and better survival in observational data. That is what made "Fistula First" a policy slogan, and for most patients who will need long-term haemodialysis a fistula remains the first choice.

But the 2019 KDOQI Vascular Access guideline deliberately moved away from a rigid hierarchy. In its place it puts the ESKD Life-Plan: an individualised, documented, annually reviewed map of the whole of a person dialysis life, covering modalities and access together, built on the ViP ACCeSS framework of Vessel Preservation, Access Creation, Contingency plan and Succession plan. The organising principle is the right access, in the right patient, at the right time (KDOQI Vascular Access, 2019).

The reasoning is not softness, it is arithmetic. A fistula is the wrong answer for a patient with a short life expectancy, poor vessels, or a high probability of failed maturation followed by months of catheter dependence anyway. Creating one in that patient buys a scar, a delay, and the catheter you were trying to avoid.

Catheters are last choice, not no choice. They carry the highest infection risk of the three access types, and KDOQI 2019 sets a facility performance goal of a catheter-related bloodstream infection rate below 1.5 infections per 1,000 catheter days. They are nonetheless the correct answer for the patient who needs dialysis this week, who has exhausted other options, or who is on a palliative trajectory.

The three options

  • Arteriovenous fistula: a surgical anastomosis between the patient own artery and vein, commonly radiocephalic at the wrist or brachiocephalic at the elbow. Highest blood flow, longest survival, lowest infection rate. Requires months to mature.
  • Arteriovenous graft: a synthetic conduit between artery and vein. Usable far sooner than a fistula, and some units cannulate early-cannulation graft materials within days. Higher rates of infection and thrombosis than a fistula.
  • Central venous catheter: a tunnelled line, usually internal jugular, with the tip near the heart. Usable immediately. Highest infection risk. The right answer when dialysis is needed now, when an access is maturing or has failed, or when nothing else is possible.

Timing and maturation

The Rule of 6s: by 6 weeks after creation, a fistula should have a blood flow of at least 600 mL/min, a diameter of at least 6 mm, a depth from the skin of 6 mm or less, and a straight usable segment of at least 6 cm for cannulation.

KDOQI Hemodialysis Adequacy / vascular access, 2006

A fistula requires months to mature before it can be cannulated; a graft can typically be used within weeks, and earlier with early-cannulation materials. Local practice varies.

NIDDK, and standard unit practice

The Rule of 6s is a guide, not a verdict, and it is routinely misapplied as a pass or fail gate. A 2022 vascular surgery analysis found that the rules do predict functional maturation, but also that many fistulas which do not meet the Rules of 6 will nonetheless support dialysis, and that flow volume plus vein depth together predict maturation about as well as all three criteria do, with vein diameter mattering less than its prominence in the rule suggests (Journal of Vascular Surgery, 2022).

Failure to mature is common. It is not a personal failure of the patient or the surgeon, and it is precisely why the Life-Plan puts a contingency and a succession plan on paper at the point of creation rather than at the point of failure.

Monitoring: the 2019 reversal

This is the change most likely to be missed, because it overturns years of routine surveillance-and-fix practice, and because it tells interventionists to do less.

Clinical monitoring of vascular access is primary; surveillance is supplementary.

KDOQI Vascular Access, 2019

Pre-emptive angioplasty of a stenosis detected on imaging, in the absence of clinical indicators, is not recommended. Intervention should require both clinical signs or symptoms and imaging confirmation of a stenosis of 50% or more.

KDOQI Vascular Access, 2019

Performance goal, the 1-2-3 rule: no more than 2 interventions to make an arteriovenous access usable, and no more than 3 interventions per year to keep it usable.

KDOQI Vascular Access, 2019

Performance goal: catheter-related bloodstream infection below 1.5 infections per 1,000 catheter days.

KDOQI Vascular Access, 2019

What clinical monitoring actually means

  • Inspect: swelling, collateral veins across the chest or shoulder, aneurysm or pseudoaneurysm, skin thinning, shininess or ulceration over the access, and the state of the needle sites.
  • Palpate: thrill quality, pulsatility (a water-hammer pulse rather than a thrill suggests outflow obstruction), and augmentation.
  • Auscultate: bruit character. A high-pitched, systolic-only bruit suggests stenosis, where a normal access gives a continuous low-pitched bruit through systole and diastole.
  • Watch the dialysis parameters: rising venous pressure, falling arterial pressure, poor achievable blood flow, prolonged bleeding after needle removal, increasing recirculation, and a falling Kt/V without another explanation.

Clinical monitoring is a physical examination performed by someone who knows what a normal access feels and sounds like, plus attention to the numbers the machine is already giving you. It is not an imaging schedule.

Complications and failure modes

  • Failure to mature: the fistula never becomes cannulable. Common, and the reason a contingency plan belongs in the Life-Plan from the start.
  • Stenosis: usually juxta-anastomotic, or in the venous outflow. Intervene on the combination of clinical indicators and a stenosis of 50% or more, not on the image alone.
  • Thrombosis: a lost thrill is time-critical. The access may still be salvageable if it is treated within hours, which is why patients are taught to check the thrill several times a day and why the unit must be able to respond same-day.
  • Infection: the dominant modifiable risk in a catheter, and the second leading cause of death in the dialysis population.
  • Aneurysm and pseudoaneurysm: a rapidly enlarging bulge, or thin, shiny or ulcerated skin over the access, is at risk of rupture and needs urgent surgical assessment.
  • Steal syndrome: distal ischaemia, presenting as a cold, painful, numb, weak or pale hand on the access side. Note the trap explicitly: a strong thrill and bruit in the fistula does not exclude steal. It is the combination of a strong thrill with distal ischaemic symptoms that supports the diagnosis.
  • High-output cardiac failure: rare, and associated with high-flow accesses.
  • Central venous stenosis: classically after previous catheters, presenting with arm swelling and prominent collateral veins across the chest or shoulder, and sometimes facial swelling.

When to refer

  • Refer for access creation early enough that it is usable when it is needed. KDIGO 2024 suggests planning for pre-emptive transplantation and dialysis access when the eGFR is below 15 to 20 mL/min/1.73 m2, or when the 2-year risk of kidney replacement therapy exceeds 40%. NICE advises starting assessment at least a year before therapy is likely to be needed.
  • Refer urgently: a lost or weakened thrill. This is a same-day problem, not a next-clinic problem.
  • Refer urgently: signs of access or exit-site infection, and any fever or rigor in a patient with a catheter.
  • Refer urgently: distal ischaemic symptoms in the access hand. Do not be reassured by a good thrill.
  • Refer urgently: a rapidly expanding aneurysm, or skin breakdown over the access.
  • Refer: arm or facial swelling and new chest wall collaterals, for assessment of central venous stenosis.
  • Refer for a Life-Plan review, not just for a procedure. An access that has needed more than 2 interventions to become usable, or more than 3 in a year to stay usable, has failed the KDOQI performance goal and the plan itself needs revisiting, not only the lesion.

Sources

  1. KDOQI Clinical Practice Guideline for Vascular Access: 2019 Update (the ESKD Life-Plan) (KDOQI, American Journal of Kidney Diseases, 2019)
  2. KDOQI Clinical Practice Guideline for Hemodialysis Adequacy, 2006 (URR and the Rule of 6s) (KDOQI, American Journal of Kidney Diseases, 2006)
  3. Rules of 6 criteria predict dialysis fistula maturation, but not all rules are equal (Journal of Vascular Surgery, 2022)
  4. Hemodialysis access: fistula, graft and catheter (NIDDK)
  5. Hemodialysis access: caring for your access (National Kidney Foundation)