Establishing Vascular Access for Dialysis

Introduction – Establishing Access

Establishing a vascular access for dialysis requires a series of steps to evaluate the urgency of need, the patient’s vascular assets (usable arteries and veins), physiological ability to support a shunt (a heart healthy enough to support a fistula or a graft), and a choice of options which will also depend on the surgeon’s experience. Once the surgery is done, a variable period for healing of a graft, or development of a fistula is required before the access is ready for use. Ordinarily, the surgeon will check the patient two or three weeks after surgery for healing and appropriate function (with grafts) and also for development with fistulas.

When the access is usable, the patient is cleared to use it, and when the access is being used without incident, the dialysis catheter (if any) is removed. This typically closes the case in most surgical practices, and closes our discussion in “Section one – establishing vascular access for dialysis”.  If the patient has problems after that, s/he is sent to an appropriate provider for additional treatment. In our practice, we offer a more comprehensive case management approach based on the idea that the surgeon who did the original surgery might be best suited to understand subsequent problems (see “Section two – Monitoring, management, maintenance and revision” below.

 

Evaluation of Hemodialysis Options for End-stage Renal Disease Patients

In the initial meeting with a new patient, an informed review of each patient’s access history is coupled with a focused physical examination and ultrasound evaluation. All factors that will affect the choice of access are reviewed. Options are discussed, and an approach (which may or may not include surgery) is recommended. In those patients whose complicated medical history or previous surgery makes additional studies necessary, every attempt is made to get those studies done and move on to the solution of the problem as soon as possible.

Our experience and knowledge of past results informs the recommendation. Education and discussion of the various choices helps the patient make a sensible choice that meets his or her individual circumstances (see “Education”, “Experience and results”, and “Access types”).

 

Office Ultrasound Examination of Veins and Arteries for Use in Dialysis Access

An ultrasound exam of both arms (usually) is done at the initial visit in the process of discovering the individual patient’s arterial and venous anatomy. There is a lot of variation between individuals, and a high incidence of damage to the veins by blood draws, IVs, PICC lines, or previous access attempts. Each patient’s inventory and pattern profoundly affects what kind of fistula can be done, and with what chance of success (see “Venous variation”, “Veins” and “Ultrasound examples”).

Arteries have been taken for granted in the past, but adequate blood supply to a fistula or graft is critical for success of the dialysis access, not to mention the blood supply to the extremity and hand beyond the access. If the artery is insufficient to support a graft, it will fail. If the inflow cannot supply the joint needs of the access and the hand, the upstream access may stay patent, but the downstream hand may not get enough blood, causing unacceptable complications of hand pain or tissue loss. There are anatomic variations in arterial supply that are frequently misunderstood, and lead to unnecessary failures (see “high bifurcation of the brachial artery”).

Patients who have previous “mapping” by ultrasound or venogram done are encouraged to bring all the information they have to the initial evaluation, but we believe that the “real time” ultrasound examination should be done by the surgeon who will do the surgery to get the best results.

Creation of Fistulas (using native veins) or Placement of Grafts (placement of Teflon tubes under the skin) for Dialysis

Once the choice as been made and the recommendation accepted, the patient is scheduled for a procedure in the hospital by Dr. Webb, who does all of his own surgery. The procedures are usually done on an outpatient basis, but the occasional patient may require an overnight stay (see “What to expect”).

On rare occasions, the patient might be recommended to have his or her procedure (e.g., thigh grafts) done by another practitioner with special skills.

Maturation of Fistulas

The creation of fistulas is an art form more like farming or glass blowing than manufacturing, and owing much to the kindness of Mother Nature. We find a more-or-less suitable vein, and attach it to a more-or-less suitable artery. The extra blood pressure and extra blood flow from the artery causes the vein to grow (usually). The process takes time, and is subject to infinite human variability. There is no 100 percent guarantee (a 65% successful maturation rate in less than six months for fistulas in the US is an accepted norm) and we have to follow our own perceptions, experiences, and statistics to achieve our goal of a usable fistula in a reasonable amount of time (see “Experience and results”).  We see people every two or three weeks after surgery to assess whether the access is ready to use, and to consider what we could do to speed the process.

We may find that the vein is big enough, but too deep to stick a needle in reliably – a superficialization may be recommended to make the fistula usable (see discussion of superficialization).

A scar tissue left from previous IVs or blood draws may create a flow-limiting narrowing that prevents the fistula from developing – a fistulogram and dilation to open up the flow may be needed to get the process back on track (see “inflow dilation”).

Branches in the vein may siphon flow away from the channel we are trying to develop – in that case, trimming of the offending branch may bolster the fistula, and make it usable earlier.

In any case, the individual situation indicates whether waiting for slow development (for a patient not yet on dialysis) is reasonable, or an aggressive re-intervention schedule (for patients with a catheter) is most reasonable

Ultrasound-assisted Digital Photo Diagrams to Guide Cannulation

Once the fistula is judged usable, we have since the beginning of Michigan Vascular Access, PC (2004) usually offered the patient the ultimate guide to cannulation. A digital photograph of the arm is taken and printed, then the fistula drawn on the printed photo with the assistance of an ultrasound examination. The course of the fistula is indicated, the size at various points, the depth below the skin at various points, location of branches, suggested areas for cannulation, and suggested areas to avoid are included. The photo-diagram is then photocopied with several copies given the patient and one for the chart. Making the access more understandable for the dialysis center personnel can reduce infiltration and make everyone’s day a little better.

Since we have created over 1700 fistulas in this time period, there are many, many examples of these photo diagrams in our archives (see access film script)