.
On November 14, 2007, Dr. Appell was recognized for his historic development of the AV fistula at the New York City meeting of the Vascular Access Society of the Americas at the Veith Symposium. In addition to being presented with an award, he was invited to give an address describing the circumstances surrounding the AVF's invention, and thoughts and observations regarding the procedure. Following is the text of his presentation:
The Concept of an A-V Fistula for Vascular Access
I would like to present to you some of the history of hemodialysis and vascular access surgery as I lived it. In 1960 the administration at the Bronx Veterans Administration Hospital decided to establish a hemodialysis clinic. A clinic in those days was an institution that did one dialysis per week. In New York City there were four such clinics: BVAH (where I was associated), Mount Sinai, Bellevue and DownState in Brooklyn.
Our dialysis machine at the BVAH was the Kolff twin coil and the team consisted of two internists, a surgeon, a lab technician and a nurse. The problem then, as it is now, was one of vascular access. The technique then employed was the use of the Scribner shunt. This shunt was developed at the University of Washington in Seattle by Quinton, Dillard and Scribner. Quinton was an engineer, Dillard a surgeon, and Scribner an internist.
The shunt in essence was a controlled AV fistula, controlled essentially by the diameter of the Teflon catheter and the connecting tubing. Such a controlled fistula is in contrast to a native AV fistula which is usually traumatic and involves large vessels. The literature at the time was replete with the adverse effects of native fistulas. They were to be avoided.
The Scribner shunt had many problems, including bleeding, infection, erosion, clotting, and the need for the patient to have a bulky dressing in order to maintain some sense of sterility.
In 1961, an article appeared in the Proceedings of the Mayo Clinic which described a ten-year study in which a group of children with a shortened limb (usually secondary to polio) were subjected to the construction of a native AV fistula in the hope that the increase in blood flow would cause a corresponding increase in limb growth. Their fistula was one half-inch in diameter and connected the superficial femoral artery with the deep femoral vein. A slight increase in heart size and heart rate and the typical murmur of an AV fistula developed in all of the children, but they appeared to tolerate these changes and these changes were reversible with closure of the fistula.
This was the first time I had found evidence in the literature which would correlate the effects of fistula size and vessels involved with the patient’s response. The consensus at the time was that all AV fistulas were to be avoided because of their adverse effects and difficulty to repair.
I reasoned that if such a large fistula involving major vessels, albeit in children, could be tolerated, would not a smaller fistula in smaller vessels be tolerated in adults.
This was my epiphany.
In February 1963 I attempted my first case. Vascular surgical instruments for this type of microsurgery were not available, so I went to the Department of Ophthalmology at BVAH and borrowed their equipment, including a loop magnifier. The first patient happened to be a very poor candidate for an AV fistula as he had very poor veins. I was, however, able to construct a side-to-side anastomosis between that small vein that crosses obliquely across the volar surface of the wrist and the radial artery. I estimated that the fistula was approximately two millimeters in diameter. I had hoped that with the increase in venous pressure additional veins would open up but this did not happen and it never does. This first case therefore was a failure as a means of vascular access but I was encouraged, because having never worked with vessels of this size before, I was able to construct a patent AV fistula.
My next case was in March 1963 and was a much better candidate. I was able to create a side-to-side radial-cephalic fistula which worked perfectly. With this success I gradually changed from Scribner shunts to peripheral AV fistulas.
My technique changed little over the years. The patient was prepped with alcohol and Betadine and the anesthesia employed was 2-percent Xylocine. A four-centimeter transverse incision was made over the anteria-lateral aspect of the wrist just proximal to the radial styloid. The subcutaneous tissue was not incised, as I felt this would offer some protection to the overlying skin and the underlying anastomosis. Disection then continued medially down to the antibrachial fascia, which was incised longitudinally. The artery was freed up over a distance that would allow easy displacement of the vessel from its bed without kinking. This latter consideration is most important in mobilizing both the artery and the vein. Vascular loops of 2-0 black silk were used to control the vessel. Disection then continued under the subcutaneous tissue at the level of the fascia to the cephalic vein located laterally in the subcutaneous tissue. The vein was likewise freed-up over a longer length than the artery but again avoiding any kinking or obstruction. At this point the patient was heparinized with 5,000 units of sodium heparin, and dilute heparin was subsequently used as an irrigating fluid. With both vessels controlled with tapes, they were brought together under the subcutaneous tissue. The tapes are used to both control position and to control blood flow; by increasing tension on the tapes, bleeding can be adequately controlled. I tried to avoid vascular clamps because I felt they were too traumatic, and besides they cluttered the field. An incision was then made with the tip of a No. 11 scalpel, and this was then enlarged to about five to six millimeters with a curved iris spring scissor. A side-to-side anastomosis was made in an over-and-over fashion with 6-0 or 7-0 silk (silk was the only available suture material at the time and it subsequently was replaced with Proline). With completion of the anastomosis, the opening should be about five millimeters. When mature, this would give a flow rate of 250 to 350 ccs per minute. The tapes are removed sequentially, first the venous side, then the distal artery, and finally the proximal artery.
A definite thrill should be palpable and venous distension may be observed. If a thrill is not present you must assume an error in technique and it should be corrected. In my experience no fistula has failed to function if a thrill was present. Careful inspection of all vessels to assure that there is no kinking or obstruction should be done. The skin was closed with interrupted nylon sutures.
Postoperatively heparin is not continued. The hand is elevated on a pillow until edema which usually occurs has subsided. Pressure bandages and elastic bandages are to be avoided.
A well constructed AV fistula can be used almost immediately, but it is better to allow a four- to six-week period for maturation to occur as this will make needling easier and give better flow.
The first ten years of access surgery at the BVAH involved 112 patients and 143 procedures. A total of 100 side-to- side and 43 end-to-side AV fistulas were constructed. One can expect a long life from a properly constructed and maintained AV fistula. For example, in 1965 Dr. Scribner sent me a patient in whom I was able to construct a peripheral fistula. In 1987, he presented that patient at a conference on vascular access in Phoenix, Arizona, and at that time the patient had had over 20 years of dialysis treatment with the same fistula. A life span of 20 to 30 years is not unheard of.
Every surgical procedure has its complications, and the peripheral AV fistula is no exception. Fortunately, they are not too common and are usually correctable without difficulty.
Aneurysms, both true and false, occur. The latter are usually the result of faulty needle technique. False aneurysms should be repaired, as they can obstruct venous drainage. True aneurysms occur at the A-V site and need not necessarily be repaired. I have never seen a peripheral aneurysm rupture. If they become unsightly or symptomatic, they should be excised and a new anastomosis constructed at a more proximal level.
Congestive heart failure is a rare complication. I preferred to treat this problem by exposing the fistula site and narrowing the stoma with well placed sutures.
The blue thumb or sore swollen hand syndrome is due to venous hypertension and should be treated by ligating any enlarged vein distal to the fistula. More frequently, however, venous hypertension is secondary to more proximal narrowing or obstruction. A brachial angiogram may be necessary to define the obstruction. Adequate bypass, e.g. venous graft or side-to-side venous anastomosis, may be necessary. Occasionally thrombectomy may be successful.
I did not encounter the “steel” phenomenon. Perhaps because the patients I encountered were younger than those you see today. I always preoperatively ascertained the competence of the ulnar artery flow by the Allen Test. I would not insert an AV fistula if it were felt that the ulnar artery was incapable of providing adequate peripheral circulation.
I would like to emphasize that the success of a vascular access program depends largely on the physician who first anticipates the subsequent need of his patient for dialysis. The venous pattern of the non-dominate arm (if available) should be protected absolutely from all attempts at bloodletting, I-Vs and I-V medication.
The concept of a peripheral AV fistula as a means for repeated access to the circulation is a concept that has established itself. It should be considered in any long-term therapy program requiring such circulatory access.
In conclusion, let me leave you with the logo of the hemodialysis unit at the University of Oklahoma -- namely, “Fistula First.”
No comments:
Post a Comment