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Vascular News RoundUp - Issue 1, May 2012

Today's Technique

AV Fistula Salvage with Artegraft
 

Dr. Jose Zamora II, Renal Transplant and Vascular Access surgeon at Sharp Memorial Hospital in San Diego, shares his technique for AV Fistula Salvage with Artegraft.

Arteriovenous (AV) fistulas have a propensity for both stenosis and aneurysmal formation at the locations of the hemodialysis needle punctures. Of course, the most common reason for surgical salvage is aneurysm formation/complication, usually from proximal venous (outflow) stenosis (i.e. Cephalic arch stenosis, etc.). As such, angioplasty is a necessary component of the fistula repair.

Aneurysmal formation and growth causes stretching of the skin with subsequent thinning or ulceration of the overlying skin. This can lead to prolonged bleeding or rupture of the AV aneurysm. In this case a “salvage” operation of the AV fistula is necessary. At the time of complication, the AV fistula has usually grown in both width and length. Often times this allows for primary aneurysm resection and re-approximation of the non-aneurysmal AV fistula vein. This operation helps maintain native vessel as the only contact with the patients’ blood; this is the main advantage of the AV fistula over almost any graft and explains its longevity as dialysis access.

However, in circumstances where the remaining AV fistula is either too short or the AV fistula needs to be “re-routed” under new skin, an interposition “jump-graft” may be used. The Artegraft collagen graft is well-suited for this purpose. The bovine carotid artery graft mimics the arterialized native fistula vein better than any PTFE graft.

The following are reported techniques that have been utilized with these AV Fistula salvage or repair procedures. These techniques are for general informational purposes only and not intended to provide medical advice. Medical professionals and health care providers should exercise their own judgment in determining whether a particular product or procedure is appropriate for their practice or their patients.

AV fistula repair with Artegraft “alternate tunnel jump-graft” (with or without aneurysm resection)

An “alternate tunnel jump-graft” with Artegraft collagen graft is useful in several situations where the skin overlying the AV fistula tunnel has questionable integrity:

  1. Exposed or ulcerated AV fistula
  2. Bleeding AV fistula
  3. Infected or indurated AV fistula

In my opinion, it is the best surgical option to bypass the area of questionable skin while both lengthening and re-routing the fistula in an alternate tunnel. I find two advantages to placing the new tunnel lateral to the existing one. First, it allows for more dialysis needle access locations. Second, it makes for an easier operation with less opportunity to kink the fistula/graft. I use the IMPRA® tunneler to both create the tunnel and to pass the Artegraft through. This can be accomplished through only two incisions, similar to a primary AV graft placement. The Artegraft is easily sewn end to end to each open end of the fistula.

In most AV fistulas larger than 8 or 9mm, the use of a 7mm (6mm I.D) Artegraft interposition will also “band” the AV fistula by diminishing the overall flow in the AV fistula. I measure intraoperative flow in all my AV fistulae and Artegrafts with the Transonic® Flow probes (Transonic Systems Inc.). They come in sizes to accommodate vessels from 3 mm to 12 mm. The flow probes can be utilized on either native vessel or the Artegraft, but not PTFE.

In the case of an infected or indurated AV fistula, I would recommend resection of the de-functionalized fistula aneurysm. The resection is usually done either with resection of the compromised skin overlying the aneurysm or leaving the skin intact by working through the existing aneurysm tunnel.

AV fistula repair with Artegraft “in-situ tunnel jump graft” and aneurysm resection

This procedure was conceived in several “clean” cases where an “alternate tunnel jump graft” was difficult or not possible due to previous, non-functional access grafts at the same site. I have used it even more, recently, to save alternate tunnel sites for eventual grafts or other fistula revisions. This operation should be utilized only when the overlying skin has good integrity and thickness. If skin integrity is questionable at all, then I would default to the “alternate tunnel jump graft” salvage with a longer Artegraft.

The same two incisions are used as in the “alternate tunnel jump graft” procedure, however resection of the aneurysmal segment of the AV fistula is performed FIRST. I resect and extract the segment “in toto” after mobilizing it through both incisions. Then, strict hemostasis and antibiotic irrigation of the existing tunnel is mandatory before placing the Artegraft. If hemostasis is marginal, then I recommend using the “alternate tunnel” procedure described above. At this point, I place the new Artegraft bypass through the existing fistula tunnel. In other words, I sew the Artegraft end to end with the existing AV fistula. Again, I measure the flow in the completed salvage fistula/graft with the appropriately sized Transonic flow probe.

AV fistula repair with Artegraft patch angioplasty

Patch angioplasty of an AV Fistula is rarely utilized since ulcerations and/or pseudoaneurysms are often resected and/or bypassed. However, when one encounters an injury to the AV fistula that does not leave the fistula “exposed” (without overlying skin), it is very feasible to utilize a split Artegraft as a patch angioplasty. First, I make sure that any questionably viable or aneurysmal vein is completely resected. Then, I will “split” the Artegraft lengthwise to create a patch for vessel repair. I have used this same method to patch and repair small non-circumferential arterial injuries. This method works well in cases when circumferential resection and Artegraft interposition is not necessary.

In either of the aforementioned presentations, using the Artegraft collagen graft for “permanent” banding of the AV fistula can help correct the problem. Regardless of your preferred fistula location for banding, one can use a short segment (2-4cm) of Artegraft wrapped around the fistula to diminish flow. Again, flow can be measured with the appropriately sized Transonic flow probe on both the AV fistula and the native artery (distal to the AV fistula anastomosis). The 7mm Artegraft can be used in concert with the Transonic probes to “dial-in” the desired flows in both the AV fistula and the distal native artery to ameliorate the steal symptoms.

Disclaimer Of Medical Liability:

ARTEGRAFT, INC. DOES NOT PROVIDE MEDICAL ADVICE. The content is for general informational purposes only and is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Reliance on any information provided in this newsletter is solely at your own risk. Individual medical needs are different; you should not assume that the information in this newsletter concerning certain courses of treatment or outcomes apply to you. Rather, you should evaluate your medical condition and make treatment decisions based upon consultation with physicians.

The content may be of interest to medical professions or other health care providers. Such content is for general informational purposes only and not intended to provide medical advice. Medical professionals and health care providers should exercise their own judgment in determining whether a particular product or procedure is appropriate in their practice or their patients.

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