Femoropopliteal bypass with externally supported knitted Dacron grafts: A follow-up of 200 grafts for one to twelve years

Purpose: This article reports our experience with externally supported, preclotted knitted Dacron grafts in femoropopliteal bypass.Methods: This is a retrospective analysis of a consecutive series of 154 patients who received 200 grafts (175 above knee and 25 below knee). Follow-up extended to 12 years (mean 59 ½ months).Results: Primary patency rates for the entire series were 75%, 70%, and 47% at 3, 5, and 10 years, respectively. Above-knee grafts had 76%, 71%, and 50% rates and 3, 5, and 10 years, respectively. Below-knee grafts had 65% and 57% at 3 and 5 years, respectively. Limb-salvage rates were 87%, 79%, and 73% at 3, 5, and 10 years, respectively, for the 57 limbs operated on because of critical ischemia. The most significant predictor of graft failure was poor runoff as determined by preoperative arteriography. The effect of poor runoff was most pronounced in the first 3 months.Conclusion: Externally supported, preclotted knitted Dacron grafts provide encouraging primary patency rates for above-knee femoropopliteal bypass. Poor leg vessel runoff is a major determinant of early graft failure. (J VASC SURG 1994;19:487-94.)     

Clinical results of femoropopliteal bypass using externally supported (EXS) Dacron grafts: with a comparison of above- and below-knee anastomosis

As of the end of September 1989, 52 EXS Dacron grafts had been implanted for femoropopliteal bypass operations. The distal ends of 27 grafts were anastomosed to above-knee popliteal arteries and those of 25 grafts to below-knee popliteal arteries. The cumulative patency rate of above-knee grafts was 71.3% at 54 months, and that of below-knee grafts was 78.8% at 48 months (n.s.). Kinking and stenosis of the arteriosclerotic proximal and/or mid popliteal artery when the knee was bent were angiographically remarkable. These changes may explain why some femoropopliteal grafts occlude with time and why the late results of above-knee grafts are not much better than those of below-knee grafts.     

Below-knee femoropopliteal bypass using externally supported polytetrafluoroethylene (PTFE) grafts

Twenty-seven externally supported polytetrafluoroethylene (PTFE) grafts were implanted in the femoropopliteal position crossing the knee joint. All patients underwent surgery because of limb threatening ischemia (rest pain or gangrene). There was one early graft failure (successful thrombectomy). No patient died postoperatively. The mean follow-up period was 17.32 months (range 3-44 months). Cumulative patency rate for this follow-up period was 73%. Absence of kinking when bending the knee joint was determined by ankle Doppler pressure measurements and arteriography. If an adequate saphenous vein is not available for knee-crossing femoropopliteal bypass, externally supported PTFE can be used, yielding short-term patency rates comparable to those obtained with autologous venous bypasses.     

A prospective randomized multicentre comparison of expanded polytetrafluoroethylene and gelatin-sealed knitted Dacron grafts for femoropopliteal bypass.

PURPOSE: To compare graft patency between expanded polytetrafluoroethylene (PTFE) and gelatin-sealed knitted Dacron for femoropopliteal bypass. METHODS: A prospective, multicentre trial was performed in 108 patients randomized to receive either a PTFE or Dacron prosthetic graft. Distal anastomosis was above knee in 75 and below knee in 33 patients. RESULTS: Primary patency at 1, 2 and 3 years was 72, 52 and 52% for PTFE, and 70, 56 and 47% for Dacron (P = 0.87). Secondary patency at 1, 2 and 3 years was 74, 54 and 54% for PTFE and 78, 70 and 53% for Dacron (P = 0.39). The most significant predictors of early graft failure were poor vessel run-off (P = 0.04) and critical limb ischaemia (P = 0.04). CONCLUSION: There was no difference in graft patency between PTFE and Dacron for femoropopliteal bypass.     

Disruption of externally supported knitted dacron graft three years after implantation--a case report

A knitted Dacron velour externally supported prosthesis was broken in two pieces at the supported portion 3 years after femoroposterior tibial bypass grafting. This type of graft problem has never been reported. Details of the clinical course, angiogram, CT scan, and scanning electron micrograph of a portion of the graft are shown. The externally supported Dacron prosthesis broke into two pieces along the broken coil of the middle portion. A possible cause of this failure may have been due to damage of the Dacron fibers in the process of heat fusing the coil. This presentation emphasizes the possibility of this rare externally supported graft complication, and the necessity for careful follow-up not only of the graft patency but also for the mechanical defects of the implanted externally supported Dacron graft itself.     

Late rupture of knitted Dacron graft.

An 87-year-old man underwent aorto-bifemoral bypass using a bifurcated Bionit II knitted Dacron graft for high aortic occlusion in 1987 at another hospital. In November, 2004, he was admitted to our institution because of difficulty in walking due to swelling and tenderness in the right groin. Computed tomography (CT) scan indicated bilateral aneurysms of the grafts in the groins. The size of the right and left aneurysms were 73 mm and 52 mm, respectively. Angiography showed some extravasation in the right thigh. We performed surgical replacement of all the dilated parts with new ringed-Dacron grafts. We report a rare case of late rupture of bifurcated Sauvage Bionit II Dacron graft.     

Clinical experience with a collagen-impregnated knitted Dacron vascular graft

This report describes our first clinical experience with collagen-impregnated Dacron grafts in the aortic position. Fifty-four consecutive patients (43 men and 11 women), average age 67.5 years (44-84), received 11 tube grafts and 23 bifurcated grafts for abdominal aortic aneurysm replacement, 17 bifurcated grafts for aortic occlusive disease, two grafts for aortic pseudoaneurysm, and one graft for thoracoabdominal aneurysm repair. No preclotting maneuvers were used and there was no blood leak from the fabric upon restoration of blood flow, in spite of the use of systemic heparin. The hospital transfusion rate averaged 1.2 units in patients with occlusive disease and 2.7 units in patients undergoing aneurysm resection, which were similar to the transfusion rate in patients receiving standard knitted grafts prior to this study. There were two postoperative deaths from a myocardial infarction and a cerebral hemorrhage and no perioperative thromboembolic events. During a follow-up averaging 41.5 months (26-59), there were two late graft limb thromboses secondary to outflow disease progression. One patient died of aspiration two months postoperatively. Four patients died secondary to cardiac disease in at 13 and 21 months with functioning grafts. The rest of the patients are alive with functioning grafts. We conclude that the collagen-impregnated Dacron graft obviates the need for preclotting maneuvers because of a zero functional porosity.     

Postoperative dilation of knitted Dacron aortic bifurcation graft

Dilation is the most common inherent "failure mode" of knitted Dacron aortic prostheses. However, the incidence of graft failure related to dilation is unknown because of insufficient data regarding the occurrence, degree, and prognostic significance of postoperative alterations in graft size. In 1979 we reported that postoperative ultrasonic examinations in 95 asymptomatic patients, selected at random after aortic surgery, revealed dilation of the aortic portion of knitted Dacron bifurcation grafts. The average follow-up was 33 months, and the mean dilation was 18%. This article provides the results of a later follow-up, averaging 175 months, in 32 patients from the 1979 study. CT scanning, rather than ultrasonic imaging, was used to evaluate all parts of the grafts. CT scans disclosed that the three parts of each graft dilated, but the parts did not always dilate uniformly. Mean percent dilation values for the entire series were aortic portion 67% +/- 38% SD; right limb 77% +/- 66% SD; left limb 54% +/- 26% SD. Maximum percent dilation for any part of the grafts ranged from 26% to 367% with a mean of 94%. At least one part of the grafts dilated 100% or greater in 12 patients. Three patients had generalized and saccular dilation of the aortic portion of the prostheses and an anastomotic aortic aneurysm; one patient had a localized aneurysm in the midportion of the right limb. Three of the latter grafts were replaced with woven Dacron prostheses.     

A 5 year follow-up of Dacron femoropopliteal bypass grafts

Over a 5 1/2 year period, 66 Dacron femoropopliteal grafts were performed for patients with an absent or unsuitable long saphenous vein. The minimum follow-up has been 6 months and cumulative patency was 50 per cent at 5 years. Twenty-five patients had critical ischaemia (preoperative Doppler ankle pressure less than 40 mmHg) and 41 patients had severe ischaemia (pre-operative ankle pressure greater than 40 mmHg). The procedure significantly improved ankle pressures in both groups and this was maintained at follow-up. In the group of 25 patients with critical ischaemia there were three operative deaths and in 10 the graft subsequently occluded, precipitating an amputation. In the group of forty-one patients with severe ischaemia, there was one operative death and in two patients the graft occluded at 18 and 24 months. In this small series there was no significant difference in patency, whether the graft was placed to the popliteal artery above or below the knee joint, or whether the popliteal had less than three patent branches at its trifurcation.     

Above-knee femoropopliteal bypass grafts and the consequences of graft failure.

In all, 290 femoral to above-knee popliteal artery bypasses were performed between January 1983 and September 1991. PTFE grafts were used in 113 cases (39%) and vein grafts in 177 (61%) (reversed in 146 cases and in situ in 31). Patients were followed up for a median time of 20 months. The 2-, 4- and 6-year patency rates for vein and PTFE grafts were 70%, 62% and 57%, respectively, compared with 58%, 46% and 41% (no statistical difference in survival curves, P = 0.2). The 2-, 4- and 6-year limb salvage rates were 82%, 78% and 62% compared with 75%, 64% and 58% (no statistical difference in survival curves, P = 0.6). A total of 99 grafts occluded during follow-up (45 PTFE and 54 vein grafts). Major amputation was required in 63 limbs; below-knee in 37 limbs (59%), and above-knee in 26 limbs (41%). There was no statistical difference in the amputation level with respect to the graft type. Final healing at the below-knee level was achieved in 23 of 35 (66%) failed vein grafts and in 14 of 28 (50%) failed PTFE grafts.     

Choice of material for above-knee femoropopliteal bypass graft

Autogenous saphenous vein is generally considered to be the best material for arterial bypass grafts below the inguinal ligament. Recent results have suggested that the advantage of vein over prosthesis is more pronounced in a distal situation, but it is not immediately apparent whether the difference is sufficient to justify a policy of using prosthesis for the initial above-knee graft to preserve the vein in case later surgery is required. An attempt has been made to answer this question. The literature has been reviewed to obtain estimates of the patency rates for grafts in different situations and a mathematical model has been set up using these figures to predict the outcome of different treatment policies. The model can be used to predict the result of alteration or inaccuracy in the data or to make use of the results of newly reported studies. The model predicts that the use of prosthesis for an initial graft will reduce the overall patency and substantially increase the requirement for reoperation, even if the present data give a substantial overestimate of the advantages of vein above the knee.     

Management of recurrent superior vena caval syndrome with an externally supported femoral vein bypass graft

Management of superior vena caval syndrome with an autogenous vein bypass graft can be complicated by occlusion of the bypass graft. The case of a patient with recurrent superior vena caval syndrome due to occlusion of a spiraled saphenous vein graft who was managed with a femoral vein graft supported externally by a sleeve of ringed polytetrafluoroethylene is presented. A venogram demonstrated patency of the graft 11 months postoperatively, and the patient remains free from clinically apparent superior vena caval obstruction 18 months postoperatively.     

Aneurysm in a double velour knitted Dacron graft

Double velour knitted Dacron grafts are currently used for aorto-iliac arterial reconstructions to increase encapsulation and enable rapid intimization of the grafts. Reports of an aneurysm arising in the body of a double velour knitted Dacron graft are rare. We experienced a case of aneurysm arising in the body of an innominate-abdominal aortic bypass graft four years after implantation. Microscopically, this focal aneurysm seemed to be related to a structural defect in the manufacturing process. We wish to stress that patients with implanted commercial Dacron prostheses should be carefully and regularly followed.     

Development of a "leak-proof," knitted Dacron vascular prosthesis

We have developed a technique to render knitted Dacron prostheses totally impervious to blood leak by impregnating the cloth with collagen. These grafts were prepared by the manufacturer, sterilized, and have an indefinite shelf life. The objective of this study was to determine whether collagen impregnation has a deleterious effect on surface thrombogenicity and graft healing. The infrarenal aortas of 30 mongrel dogs were replaced with 6 cm X 6 mm Dacron grafts (15 collagen-impregnated and 15 control). The collagen-impregnated prostheses were visibly indistinguishable from the control. After blood flow was restored, no interstitial bleeding occurred in the collagen grafts, in contrast to the control grafts that initially leaked profusely. When they recovered, the dogs were divided into three groups: group I (five collagen, five control), group II (five collagen, four control), and group III (five collagen, three control). The grafts were harvested at 3, 6, and 9 months, respectively. Retroperitoneal healing response, capsular thickness and adherence, completeness of neointimal healing, surface fibrinolytic activator activity, and sections taken for light and scanning electron microscopy were studied and compared in a blinded fashion. In a separate set of experiments, experimental and control grafts were compared for in vivo surface thrombogenicity. The healing data were identical in the experimental and control prostheses in all parameters. Of particular interest was that initial capsule adherence was better and surface thrombogenicity less in the collagen-impregnated prosthesis. We conclude that collagen impregnation of a knitted Dacron prosthesis has no deleterious effect for the term of observation of this experiment.     

Comparison between saphenous vein and Dacron Velour grafts for femoropopliteal bypass.

One hundred and thirty-eight femoropopliteal grafts were performed for arteriosclerotic occlusive disease of the femoral artery in a five-year period. One group of patients who had 81 saphenous vein grafts was compared with a similar group who had 57 Dacron Velour grafts. At three years 90% of the vein grafts were patent, compared to 45% of the Dacron Velour grafts. Twenty-seven per cent of all patients presented with threatenened limb loss. Amputation was averted in all but 5%. Intraoperative flow measurement did not prove to be a reliable indicator of long-term patency.     

Heparin-bonded Dacron or polytetrafluoroethylene for femoropopliteal bypass grafting: a multicenter trial

BACKGROUND: Dacron (polyester fiber) was largely abandoned for femoropopliteal bypass grafts 30 years ago because saphenous vein achieved better patencies. However, in patients taking aspirin, patency in above-knee femoropopliteal bypass grafts has recently been shown to be equivalent to that with saphenous vein. We compared heparin-bonded Dacron (HBD) and polytetrafluoroethylene (PTFE) in a randomized multicenter trial including below-knee popliteal or tibioperoneal trunk bypass graft where the long saphenous vein was absent or inadequate. METHODS: Over 28 months, 209 patients undergoing femoropopliteal bypass grafts (180 above-knee, 29 below-knee) were randomized to HBD (n = 106) or PTFE (n = 103). Each patient was given aspirin (300 mg/d) before surgery, and this continued unless the patient had intolerance to the aspirin. RESULTS: The mean follow-up was 42 months (range, 28-55). Fifteen (7.1%) patients died with patent grafts, and three (1.4%) infected grafts were removed. Patency (measured with Kaplan-Meier survival analysis) at 1, 2, and 3 years for HBD was 70%, 63%, and 55% compared with 56%, 46%, and 42%, respectively, for PTFE (P =.044). A total of 67 secondary interventions were performed on 48 thrombosed grafts; long-term patency was achieved in only three. Risk factors for arterial disease did not significantly influence patency. Amputations have been performed in 23 patients, six after HBD and 17 after PTFE bypass grafts (P =.015). CONCLUSIONS: HBD achieved better patency than PTFE, which carried a high risk of subsequent amputation.     

A five-to seven-year experience with externally-supported Dacron prostheses in axillofemoral and femoropopliteal bypass

We have examined the clinical results of 56 externally-supported (EXS) Dacron grafts in the axillofemoral position and 117 in the femoropopliteal position. Results have been analyzed from two perspectives: primary patency concerns only those grafts that had never occluded; extended patency refers to all open grafts including those whose continued patency is the result of thrombectomy. The 5-to 7-year life-table patency rates are: axillofemoral 8 mm and 6 mm bypass: primary 75% and extended 97%; above-knee femoropopliteal 6 mm bypass: primary 78% and extended 93%; below-knee 6 mm femoropopliteal bypass: primary 41% and extended 91%. In contrast, the results for the 5 mm grafts used for femoropopliteal bypass were inferior to the 6 mm grafts: femoropopliteal 5 mm bypasses had an above-knee primary patency rate of 44% and an extended rate of 55%, with a below-knee primary patency rate of 15% and an extended rate of 32%. Rendering the noncrimped porous Dacron prosthesis kink and compression resistant by an external support coil appears to increase its potential for successful use, especially in 8 mm axillofemoral and 6 mm femoropopliteal bypasses. Presented to the Western Vascular Society, January 1986, Laguna Niguel, California.