Long-Term Results of Saphenous Vein Graft

Arteriovenous Fistulas

James May, FRACS, Sydney, Austraki

John Harris, FRACS, Sydney, Australia

John Fletcher, FRACS, Sydney, Australia

It is generally agreed that the radial artery to cephalic vein arteriovenous fistula described by Brescia et al [I] in 1966 is the best method of obtaining access to the circulation. There is, however, a significant group of patients whose arteries or veins are unsuitable for the construction of such a fistula. It was for these patients that the autogenous saphenous vein graft arteriovenous fistula was introduced by May et al [2]. Although this procedure has been widely used, there is a paucity of reports in which a large number of patients have been followed up for a period of years. Encouraging claims have been made from time to time for alternative graft materials such as man- dril-grown grafts [3], bovine heterografts [4] and, more recently, polytetrafluoroethylene grafts [5]. In view of the cost and complications of some of these alternative materials, it was considered important to establish a baseline for comparing the performance of saphenous graft arteriovenous fistulas. Our ex- perience with 70 patients having this type of access operation is presented with the following aims: (1) to establish the long-term patency rates for these grafts so they may be compared with the patency rates of alternative methods, (2) to assess the effect of renal transplantation on the patency rate of the grafts, (3) to measure the intraoperative blood flow through the grafts and assess the prognostic value of flow mea- surement as an indicator of long-term patency, and (4) to examine the complications associated with these grafts.

Material and Methods

A total of 71 grafts have been used for hemodialysis in 70 patients, 44 women and 26 men with a mean age of 44

From Tha department of Swgery, University of Sydney, and the Royal Prince Alfred Hospital, Newtown, Sydney, Australia.

Requests for reprints should be addressed to James May, MS. FRACS, Royal Prince AIf@ Hospital Medical Centre. lob Carillon Avenue, Nawtown 2042, Sydney, Australia.

f 12.9 (standard deviation) years. The technique originally described by May et al [z] was used. The operations were performed under general anesthesia as a combined syn- chronous procedure with two operating surgeons. While the saphenous vein was removed from the leg, the brachial artery and a suitable vein were exposed in the cubital fossa of the nondominant arm. The prepared saphenous vein was tunnelled subcutaneously in a loop on the forearm. The ends were anastomosed end to side to the previously pre- pared artery and vein in the cubital fossa. The thigh wounds were closed with suction drainage. Intraoperative flow measurement was performed using a square wave electromagnetic flow meter in 43 grafts. Follow-up was complete and was assessed at the Dialysis Centre or Transplantation Clinic. The cumulative patency rate was calculated according to the modified life table method for the entire group. The patients were divided into those who subsequently received a kidney transplant and those who did not. Cumulative patency rates were calculated for the two groups.

Results

Patency rate: The patency rates for the 71 grafts are shown in Table I. Grafts that were patent up to the time of death were recorded as patent with fol- low-up lost due to death of patient. The number of grafts at risk after 36 months is too small to draw valid conclusions, due largely to the significant mortality for reasons other than the saphenous vein grafts. The cumulative patency rates are shown in Figure 1. Sixty-six percent of the grafts were patent at 2 years and 40 percent at 3 years.

Affect of renal transplantation on patency rates: Renal transplantation was performed in 29 patients with a functioning vein graft. The remaining 41 patients with 42 vein grafts did not receive a renal transplant. The cumulative patency rates for these two groups are shown in Table II. There was no sta- tistically significant difference in the cumulative patency rates for the two groups (Figure 2).

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May et al

100

90

60

70

60

PATENCY

w So

0 6 12 19 24 30 36 42 49

TIME (Months)

Figure 1. Cumulative patency rates for 71 saphenous vein graft afterlovenous ftsttdas.

Intraoperative blood flow measurements: Blood flow through the saphenous vein grafts was measured at operation in 43 patients. The mean flow was 296 ml/min (range 30 to 650). There was no sta- tistically significant difference in the mean flow at operation in the 29 patients whose grafts remained patent (311 f 171 ml/min) and in the 14 patients whose grafts subsequently occluded (262 f 145 ml/min). Scattergrams demonstrated a uniform distribution of flow rates in both groups.

Complications: Despite deaths due to other causes, no death was directly related to either anes- thesia or surgery for the construction of the saphe- nous vein graft arteriovenous fistulas. Three patients required ligation of grafts for infective complications. All had episodes of septicemia. In two patients can- nulation sites were infected with Staphylococcus aureus and Staphylococcus albus. In the third patient generalized thrombophlebitis occurred in the graft.

TABLE I Data on 71 Saphenous Veln Grafls

100 \

\ 90 ‘.

90 R

l Transplant Group m Non-transplant Group

\

.‘\ I i I

60

PATENCY

(%) 5o

40

‘~--?--,

\

\ \

\ l ‘.

\

\ \ \

.+

i

10 t I ’ ’ ’ ’ ’ ’ 1

0 6 12 1% 24 30 36 42

TIME (Months)

Figure 2. Cumulative patency rates for 42 saphenous vein graff arteritwenaw fktuias~ In patients who dtd not receive a renal transplant compared w/th 2s simflar flstutas in pa- Vents who did receive a renal transplant.

Two patients developed steal syndromes that re- quired ligation of their grafts; both had severe isch- emit symptoms but neither developed gangrene or ischemic ulceration in the affected arm. Although one patient developed gross ectasia in the venous runoff, no patient had hemodynamic cardiac complications as a result of excessive flow through the arteriovenous fistula. In two patients graft occlusion was associated with low cardiac output due to pericardial effusion. No patient had graft stenosis or false aneurysm.

Comments

The use of saphenous vein arteriovenous fistulas in this series was reserved for patients in whom a satisfactory radiocephalic fistula could not be formed. The reported number of patients requiring such a secondary procedure varies from 9.8 percent

Interval No. of Grafts Grafts No. of Duration of Occlusion

(mo) at Risk Occluding DsathS Follow-Up’ Rate (%)

O-6 71 7 8 0 10.4 6-12 56 7 6 3 13.6

12-18 40 4 3 4 11.0 18-24 29 1 0 11 4.3 24-30 17 2 1 4 13.7 30-36 10 2 2 4 26.6 36-42 2 0 0 ‘2 0

l Grafts that are still patent but have a length of follow-up within the specified interval.

Patency Cumulative Standard Rate (%) Patency (% ) Error (%)

89.6 89.6 3.7 86.4 77.4 5.4 89.0 68.9 6.2 95.7 66.0 6.6 86.3 57.0 8.7 74.4 40.7 11.4

100.0 40.7 11.4

366 llw Amerkan Journal of Sur9Ory

[6] to 22.0 percent [7]. More women than men require this procedure because women generally have smaller superficial veins and therefore greater difficulty in having a satisfactory radiocephalic fistula formed.

The 66 percent cumulative patency rate for the total group at 2 years compares favorably with the 35 percent rate for the same period reported by Morgan and Lazarus [6] in 99 grafts at the Peter Bent Brig- ham Hospital. However, there is a steady thrombosis of grafts after 2 years so that the cumulative rate in the present series was reduced to 40 percent at 3 years. It has generally been assumed that the return to normal coagulation after renal transplantation is associated with an increase in thrombosis of arte- riovenous fistulas. In the present series, however, there was no significant difference in the cumulative patency rates in the transplant and the nontrans- plant groups.

Previous investigators have noted more problems with loop grafts on the forearm than with straight grafts from either the radial or ulnar arteries distally to the veins in the cubital fossa. Haimov et al [8] re- ported a 6 percent patency rate at 2 years in 14 pa- tients with loop grafts compared with a 75 percent rate at 2 years in 13 patients with straight grafts. Similarly, Girardet et al [9] reported stenosis in 5 of 12 loop grafts compared with one stenosis in 14 straight grafts. The reason for this is not clear but does not appear to be technical because the loss of patency occurred steadily over 2 years rather than in the immediate postoperative period in the study of Haimov et al. Nor do the stenoses in the patients of Girardet et al appear to be related to cannulation, as

Saphenous Vein Arteriovenous Fistulas

three of the five stenoses occurred in grafts that had never been used for dialysis.

However, patency should not be the only standard by which saphenous vein grafts are judged as a means of providing access. The grafts are safe in that no deaths were attributable to their insertion. Similarly, there were no major complications such as life- threatening secondary hemorrhage or loss of limb. The average stay in hospital tends to be longer than patients in whom an alternative graft material is used, due largely to the need to provide closed suction drainage in the leg after excision of the saphenous vein.

Intraoperative measurement of blood flow through the graft did not prove useful as an indicator of long-term patency. Although the mean flow at op- eration through the grafts that remained patent was slightly higher than in those that subsequently oc- cluded (311 versus 262 ml/min, respectively), there was no statistically significant difference between the two groups. Factors other than the magnitude of flow, such as repeated cannulation and the general state of the patient’s coagulation mechanism, appear re- sponsible for subsequent thrombosis. The lack of necessity for cannulation after transplantation may balance the improvement in coagulation and account for the similarity in patency rates for the two groups.

Summary

The long-term results of autogenous saphenous vein grafts for vascular access were examined in 70 patients. The cumulative patency rate was 66 percent

TABLE II Data on Sephenous Vein Gratts in Patients With and Without Renal Transplantation

Transplant Group

Interval No. of Grafts Grafts No. of Duration of Occlusion Patency Cumulative Standard (mo) at Risk Occluding Deaths Follow-Up* Rate t%) Rate (% 1 Patencv ( % ) Error t % )

O-6 29 5 6 6-12 12 2 0

12-18 8 0 0 18-24 7 1 0 24-30 4 1 1 30-36 2 0 0

6 27.7 76.3 76.3 6.6 2 18.2 81.8 64.0 11.5 1 0.0 100.0 64.0 11.5 2 16.7 83.3 53.4 13.7 0 28.6 71.4 38.1 16.2 2 0 100.0 38.1 16.2

Nontransplant Group

O-6 42 5 6 0 12.8 87.2 87.2 5.4 6-12 31 5 4 2 17.9 82.2 71.6 8.9

12-18 20 2 2 1 10.8 89.2 63.9 9.8 18-24 15 0 0 8 0.0 100.0 63.9 9.8 24-30 7 1 1 2 18.2 81.8 52.3 12.6 30-36 3 1 0 2 40.0 60.0 31.4 28.8

* In the transplant group, renal transplantation was performed a mean of 9 months after graft construction. In the nontransplant group, data refer to grafts that are still patent but have a length of follow-up within the specified interval.

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May et al

at 2 years and 40 percent at 3 years. No difference could be detected in the occlusion rate of grafts in patients who received a kidney transplant and those who did not. Intraoperative measurement of blood flow through the grafts did not prove useful as an indicator of long-term patency. No deaths were at- tributable to the grafts, and major complications were limited to infection in three patients and distal ischemia in two; these complications necessitated ligation of the graft in all five patients.

References

1. Brescia MJ, Cimino JE, Appel K, Hurwich BJ. Chronic haemo- dialysis using venipuncture and a surgically created arterio- venous fistula. N Engl J Med 1966;275:1089.

2. May J, Tiller D, Johnson J, Stewart J, Sheil AGE. Saphenous vein arteriovenous fistula in regular dialysis treatment. N Engl J Med

1969;280:770. 3. Beemer RK, Hayes JF. Haemodialysis using a mandril grown

graft. Trans Am Sot Artif Intern Organs 1973;19:43. 4. Butt KM, Rao TKS, Maki T, et al. Bovine heterograft as a pref-

erential haemodialysis access. Trans Am Sot Artif Intern Organs 1974;20 B:339.

5. Butler HG, Baker LD, Johnson JM. Vascular access for chronic haemodialysis: polytetrafluoroethylene (PTFE) versus bovine heterograft. Am J Surg 1977;134:791.

6. Morgan A, Lazarus M. Vascular access for dialysis. Am J Surg 1975;129:432.

7. Martin0 A, Buetow G, Sherlock J, Letteri J. Three years experi- ence with autogenous and homologous saphenous vein graft for maintenance haemodialysis. Trans Am Sot Artif Intern Organs 1974;20:335.

8. Haimov M, Burrows L, Baez A, Neff M, Slifkin R. Alternatives for vascular access for haemodialysis: experience with autoge- nous saphenous vein autografts and bovine heterografts. Surgery 1974;75:447.

9. Girardet RE, Hackett RE, Goodwin NJ, Friedman EA. Thirteen months experience with the saphenous vein graft arteriove- nous fistula for maintenance haemodialysis. Trans Am Sot Artif Intern Organs 1970;16:285.

390 The American Journal of Surgery