Saphenous vein versus PTFE for above-knee femoropopliteal bypass. A review of the literature.

The autogenous saphenous vein is considered the best bypass graft material for arterial bypasses below the inguinal ligament. However, a synthetic graft or prosthesis is considered an acceptable alternative, especially when the distal anastomosis is situated above the knee. Some studies even suggest that patency rates for vein and synthetic grafts are comparable, whereas others indicate that a vein graft is superior to a prosthetic graft, even above the knee. To test the hypothesis that both vein grafts and synthetic prostheses are equally beneficial in the above-knee position, we performed a systematic review of available studies comparing the patency of saphenous vein and polytetrafluoroethylene (PTFE) as bypass material. English and German medical literature from 1966 to 2002 was searched using Medline, and 25 articles meeting our inclusion and exclusion criteria were selected. The patency of venous bypasses was superior to that of PTFE bypasses at all time intervals studied. After 2 years, the primary patency rate of venous bypasses was 81% as compared to 67% for PTFE bypasses, and after 5 years it was 69 and 49%, respectively. After 5 years, the secondary patency of PTFE bypasses reached 60%. When only randomized trials were considered, venous bypasses were again superior to PTFE bypasses at all intervals studied. After 2 years, the primary patency rate of venous and PTFE bypasses was 80 and 69%, respectively, and after 5 years it was 74 and 39%, respectively. Since both randomized and retrospective studies comparing venous with PTFE bypasses showed that vein grafts were 'better' than PTFE prostheses, the null hypothesis that there is no difference between the two types of graft material was rejected (p=0.008). We conclude from this systematic review that if a saphenous vein is available, a venous bypass should be chosen at all times, even if patients have an anticipated short life expectancy (<2 years). If the saphenous vein is absent or not suitable for bypass grafting, PTFE is a good alternative as bypass material.     

Polytetrafluoroethylene versus human umbilical vein in above-knee femoropopliteal bypass: six-year results of a randomized clinical trial.

In a prospective, randomized trial 6 mm polytetrafluoroethylene (PTFE) and 6 mm human umbilical vein (HUV) were compared in above-knee femoropopliteal bypass grafting. In claudicants a prosthetic graft was used intentionally, in limb-salvage cases only when autologous vein was insufficient. Ninety-six extremities were randomized (49 PTFE and 47 HUV). Operative indication was disabling claudication in 77 and limb salvage in 19 extremities. The two groups were comparable as to preoperative risk factors and operative and postoperative treatment. Median follow-up was 76 months (range 47 to 91 months), during which 23 patients died of nonrelated causes with functioning grafts. Thirty-eight grafts failed (33 because of occlusion and five for other reasons). At 6 years the primary patency rate was 38.7% in the PTFE group and 71.4% in the HUV group (p < 0.001). Corresponding rates for secondary patency at 6 years were 51.4% and 76.4% (p < 0.005).     

The multiple sequential distal bypass graft: seven-year follow-up

Thirty-nine infrainguinal bypass grafts with multiple sequential distal anastomoses were performed on 35 patients ranging in age from 32 to 79 years (mean 65.8 years) with severe femoropopliteal occlusive disease. Thirty-eight procedures were performed for limb salvage indications. Distal anastomoses were performed to the popliteal-anterior tibial arteries in seven procedures, the popliteal-posterior tibial arteries in six, the popliteal-peroneal arteries in six, the anterior tibial-peroneal arteries in eight, the posterior tibial-peroneal arteries in 10, and the posterior tibial-anterior tibial arteries in two. Saphenous vein was the graft material in 31 procedures (in situ in two), polytetrafluoroethylene (PTFE) in four, and saphenous vein-PTFE composite in four. The mean Doppler ankle-arm index was 0.38 +/- 0.14 preoperatively and 0.89 +/- 0.13 postoperatively. The early (30-day) graft patency rate was 93%. With life-table analysis, the long-term primary patency rate was 70% at 1 year, 61% at 3 years, and 52% at 7 years for saphenous vein grafts; the secondary patency rate was 65% at 7 years for saphenous vein grafts. The secondary patency rate for PTFE and PTFE-vein composite grafts was 75% at 1 year, 50% at 3 years, and 17% at 5 years. Cumulative life-table limb salvage rates were 91% at 1 year, 85% at 5 years, and 61% at 7 years. The multiple sequential distal bypass graft is durable and highly efficacious in achieving limb salvage.     

A retrospective analysis of infra-inguinal arterial reconstruction: three year patency rates.

Primary infra-inguinal arterial reconstructions were reviewed for primary patency and outcome of thrombosis in 144 patients. Distal anastomoses in these patients were to the popliteal artery and were above the knee in 63, below the knee in 53 and at the tibial level in 28. The treatment used was: polytetrafluoroethylene (PTFE) in 33 cases, PTFE with an interposition vein cuff in 29 cases, autogenous saphenous vein (ASV) in situ in 47 cases, and reversed technique in 26 cases. Life table analysis showed a 59% overall primary patency at 3 years. Patency rates of above knee anastomoses (65%) and below knee (61%) were statistically different from the tibial anastomoses (42%, P = 0.005). In both above and below knee popliteal anastomoses there was a statistically significant difference in the patency of ASV and the PTFE/vein cuff technique (P = 0.0006) but there was no difference between ASV and PTFE. There was no difference in patency rates for the various types of grafts with tibial anastomoses. Data were analysed at 3 years, taking into account the variables of smoking, diabetes or indications for surgery respectively and no difference was found in patency. The number and calibre of the run-off vessels did not influence patency significantly, hence anastomosis to any good quality vessel regardless of run-off is recommended. The poor results with the interposition vein cuff technique are unexplained but this study suggests that the technique should be reserved for anastomoses below the popliteal artery.     

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.     

Patency and Limb Salvage for Polytetrafluoroethylene Bypasses with Vein Interposition Cuffs

Polytetrafluoroethelene (PTFE) is often utilized in patients with limb-threatening ischemia requiring infrainguinal revascularization in the absence of autologous saphenous vein. To increase long-term patency of PTFE grafts, vein interposition cuffs have been recommended as adjunctive procedures. The purpose of this study was to assess the efficacy of vein interposition cuffs on the long-term patency and limb salvage of patients requiring prosthetic bypass grafts for limb-threatening ischemia. Prosthetic bypass grafts with vein interposition cuffs (PTFE/VC) were performed on 56 limbs in 55 patients (32 men, 23 women; mean age of 67 years) from October 1993 to January 1998. Grafts were prospectively evaluated every 3 months for the first 12 months and biannually thereafter with duplex ultrasonography. PTFE/VC and PTFE bypasses at the popliteal level appear to have comparable patencies. However, PTFE/VC appear to offer an improved patency and limb salvage for infrapopliteal bypasses in patients with critical limb ischemia. When infrapopliteal revascularization is required in the absence of autologous saphenous vein, we recommend the use of PTFE with vein interposition cuffs.     

Infrainguinal bypass surgery: factors determining late graft patency

The results of 373 infrainguinal bypass grafts, in a single centre, between 1980 and 1988 are reviewed. One hundred and thirty in situ vein (ISV), 47 reversed saphenous vein (RSV), 118 polytetrafluoroethylene (PTFE) and 78 human umbilical vein (HUV) grafts were used. The indications for surgery were disabling claudication in 25 per cent of patients and limb salvage in 75 per cent. In 36 per cent of operations the distal anastomosis was above the knee and in 64 per cent it was below the knee. Overall 5-year patency rates and limb salvage rates respectively were, for ISV (41 and 69 per cent), RSV (62 and 90 per cent), PTFE (31 and 67 per cent) and HUV (29 and 59 per cent). There was no significant difference in patency among these grafts at the above-knee level, but significant differences between vein and prosthetic grafts were evident below the knee (P less than 0.001). Using a proportional hazards model the three factors that consistently correlated with late graft patency were graft type (P less than 0.001), site of distal anastomosis (P less than 0.001) and distal run-off (P less than 0.001). Overall, the results suggest that prosthetic grafts are a suitable alternative to autogenous vein when the distal anastomosis is above the knee, but vein should always be used, if available, below the knee joint.     

Long-term results of femoro-popliteal/tibial bypasses with special references to re-operation in former femoro-popliteal procedures

Since 1962 a total of 1,361 femoro-popliteal/tibial reconstructions have been performed and followed up. In addition to the saphenous vein, Dacron, PTFE, and umbilical vein grafts were used. The following long-term results were achieved: The saphenous vein grafts have a patency of 73.6% after 10 years and of 52.2% after 17 years. Cumulative patency rate for the PTFE grafts were 76.4% after 39 months with above knee and 62.2% after 2 years with below knee reconstructions. After 12 months 85.7% of the umbilical vein grafts were functioning.     

Femoropopliteal bypass with either adequate ipsilateral reversed saphenous vein or obligatory polytetrafluoroethylene

The results are presented of a 10-year experience with 312 femoropopliteal bypasses performed in 285 patients using ipsilateral autologous reversed greater saphenous vein when available and adequate and polytetrafluoroethylene (PTFE) when not. The indications for operation were severe claudication in 121 (39%), rest pain in 95 (30%), and minor tissue loss in 96 (31%) limbs. There were 235 (75%) saphenous vein bypasses, of which 157 were above and 78 below the knee, and 77 (25%) PTFE bypasses, 58 above and 19 below the knee. Of these, 232 (79%) saphenous vein and 62 (21%) PTFE bypasses were primary procedures. The 30-day mortality rate was 3% (7/285) and the 30-day amputation rate was 2% (6/312). Overall, 24 (10%) saphenous vein and 30 (39%) PTFE grafts ultimately failed. The cumulative primary patency of all bypasses was 77% ± 4% (mean ± 1 SE) (85% to 69%, 95% confidence interval) at 3 years and 75% ± 4% (86% to 64%) at 5 years. Saphenous vein primary patency was superior to that of PTFE at 3 years, 87% ± 4% (97% to 77%) vs. 54% ± 12% (65% to 41%), (p<0.01), and at 5 years, 81% ± 6% (96% to 67%) vs. 48% ± 16% (63% to 33%) (p<0.01). Above-knee saphenous vein bypass primary patency was slightly better than below-knee patency at 3 years, 89% ± 4% vs. 84% ± 6%, and at 5 years, 83% ± 7% vs. 80% ± 8%. This was superior to above-knee PTFE patency at 3 years, 54% ± 14%, and at 5 years, 34% ± 16% (p<0.01). The overall PTFE failure rate was three to four times that of the saphenous vein rate. These results strongly support the use of autologous greater saphenous vein for all femoropopliteal bypasses when it is available and of good quality. PTFE grafts are valuable secondary conduits when the vein is not available or is inadequate. This series was not randomized since PTFE was used only in patients with inadequate or unavailable ipsilateral greater saphenous veins. When this protocol was followed, the patency rate for greater saphenous vein was excellent and its use is recommended for femoropopliteal bypass when it is available and of good quality.Presented in part at the Fortieth Annual Meeting of the North American Chapter of the International Society for Cardiovascular Surgery, Chicago, Ill., June 9– 10, 1992.     

A RETROSPECTIVE ANALYSIS OF INFRA-INGUINAL ARTERIAL RECONSTRUCTION: THREE YEAR PATENCY RATES

Primary infra-inguinal arterial reconstructions were reviewed for primary patency and outcome of thrombosis in 144 patients. Distal anastomoses in these patients were to the popliteal artery and were above the knee in 63, below the knee in 53 and at the tibial level in 28. The treatment used was: polytetrafluoroethylene (PTFE) in 33 cases, PTFE with an interposition vein cuff in 29 cases, autogenous saphenous vein (ASV) in situ in 47 cases, and reversed technique in 26 cases. Life table analysis showed a 59% overall primary patency at 3 years. Patency rates of above knee anastomoses (65%) and below knee (61%) were statistically different from the tibial anastomoses (42%. P = 0.005). In both above and below knee popliteal anastomoses there was a statistically significant difference in the patency of ASV and the PTFE/vein cuff technique (P= 0.0006) but there was no difference between ASV and FTFE. There was no difference in patency rates for the various types of grafts with tibial anastomoses. Data were analysed at 3 years, taking into account the variables of smoking, diabetes or indications for surgery respectively and no difference was found in patency. The number and calibre of the run-off vessels did not influence patency significantly, hence anastomosis to any good quality vessel regardless of run-off is recommended. The poor results with the interposition vein cuff technique are unexplained but this study suggests that the technique should he reserved for anastomoses below the popliteal artery.     

Composite sequential grafts in severe ischemia: a comparative study

From October 1978 to June 1983, 64 sequential bypass grafts were performed in 59 patients with limb-threatening ischemia. These patients were classified into three study groups as follows: reversed saphenous vein graft alone (12), composite sequential (proximal polytetrafluoroethylene [PTFE] and distal vein) graft (30), and PTFE graft in entirety (22). Graft patency was confirmed in all cases by serial Doppler ankle pressure measurements or by angiography. Cumulative life-table patency rates were then compared over a period of 27 months. The patency rates for composite sequential grafts using a distal short segment of vein were statistically indistinguishable from those for bypasses performed entirely with saphenous vein. These yielded a patency rate of 80% at 1 and 2 years. In contrast, the 1- and 2-year patency rates of the PTFE sequential grafts were 52% and 47%, respectively (p less than 0.05). Composite sequential bypasses using an otherwise inadequate segment of saphenous vein are a sound alternative revascularization procedure, with a patency rate comparable to that of reversed saphenous vein bypasses.     

Fluoropolymer coated Dacron or polytetrafluoroethylene for femoropopliteal bypass grafting: a multicentre trial

Background: This trial was designed to compare graft patency between expanded polytetrafluoroethylene (PTFE) and fluoro­polymer coated Dacron for femoropopliteal bypass in patients in whom saphenous vein was unavailable. Methods: A multicentre prospective trial randomized 129 patients (74 men, 55 women) who underwent femoropopliteal bypass using either a PTFE or fluoropolymer coated Dacron graft. The indication for operation was disabling claudication in 68 (52.7%) and critical limb ischaemia in 61 (47.3%) patients. Distal anastomosis was above the knee in 76 (58.9%) and below the knee in 53 (41.1%) patients. Results: Primary patency at 6, 12 and 24 months was 71%, 56% and 47% for PTFE and 50%, 36% and 36% for fluoropolymer coated Dacron (P = 0.002), respectively. Secondary patency at 6, 12 and 24 months was 77%, 60% and 48% for PTFE and 66%, 49% and 46% for fluoropolymer coated Dacron (P = 0.13), respectively. The superior primary patency of PTFE over fluoropolymer coated Dacron was most evident in patients with poor prognostic indicators for graft survival: critical limb ischaemia (P = 0.001); below‐knee anastomosis (P = 0.01); and smaller (6 mm) diameter grafts (P = 0.002). Graft thrombosis developed in the first month in 22 of 61 (36%) patients receiving fluoropolymer coated grafts compared to six of 68 (8.8%) patients receiving PTFE, which accounts for the difference in primary patency. Successful thrombectomy in 10 of the 22 fluoropolymer coated grafts resulted in similar secondary patency. Conclusion: Polytetrafluoroethylene has superior primary patency and similar secondary patency to fluoropolymer coated Dacron. These results support the preferential use of PTFE in patients with critical limb ischaemia, especially when a below‐knee distal anastomosis and smaller diameter graft is required.     

Polytetrafluoroethylene grafts as the first-choice arterial substitute in femoropopliteal revascularization

We studied a series of femoropopliteal bypass operations in which polytetrafluoroethylene (PTFE) grafts were used as the first choice, regardless of the availability of saphenous vein. From Jan 1, 1979 to Dec 31, 1982, 63 PTFE femoropopliteal bypass grafts were placed in 55 patients without exploration of the saphenous vein. Forty-three grafts were placed for limb salvage, and 20 grafts were placed for disabling claudication. Patients were followed up for nine to 53 months (average, 23 months). The operative mortality was 1.8%. There were no infections. The overall patency at 30 months was 76.1%. The 30 months' cumulative patency rate for patients with claudication was 89.3%, and there were no amputations. The cumulative 30-month patency for limb salvage was 70.1%, and there was a limb salvage rate of 81.2%. Because the 30-month results were comparable with reported series using autogenous saphenous vein, we concluded that PTFE conduits may be considered the first-choice arterial substitute for femoropopliteal reconstruction. Until longer follow-ups are available, reversed autogenous saphenous vein should probably be the graft of first choice in younger patients (less than 60 years of age) without coronary artery disease who are undergoing femoropopliteal revascularizations.     

Multicenter Randomized Prospective Trial Comparing a Pre-cuffed Polytetrafluoroethylene Graft to a Vein Cuffed Polytetrafluoroethylene Graft for Infragenicular Arterial Bypass

Poor patency of synthetic grafts for infragenicular revascularization has led to use of distal vein patches or cuffs. The aim of this study was to compare the distally widened Distaflo^TM PTFE graft, which mimics a vein cuff, with a PTFE graft with distal vein modification. In this prospective, randomized, multicenter trial we compared use of a precuffed PTFE graft wit that of PTFE grafts with distal vein modification for infragenicular revascularization in patients with critical limb ischemia without saphenous vein. Study end points were primary and secondary patency and limb salvage rates at 2 years. From January 28,1999 to November 1, 2000, 104 patients were enrolled in 10 North American centers. Thirteen were excluded for protocol violation. Ninety-one bypasses were performed in 89 patients with a mean age of 73 years (range 47-90). By randomization, 47 bypasses were done with the precuffed graft and 44 with PTFE graft with vein cuff. Both groups were comparable for comorbidities and operative variables, except for a higher incidence of acute ischemia in the precuffed group (19% vs. 4.5%, p = 0.03). Bypass was a redo procedure in 53% and was performed at the infrapopliteal vessels in 79%. Operative mortality was 2.2% (2/91). Mean follow-up was 14 months (range 1-30). At 1 and 2 years, primary patency was 52% and 49% for the precuffed group and 62% and 44% for the vein cuffed group, respectively (p = 0.53). At 1 year and 2 years, the limb salvage rate was 72% and 65% for the precuffed group and 75% and 62% in the vein cuffed group (p = 0.88). Although numbers are small and follow-up short, this midterm analysis shows similar results for the Distaflo precuffed grafts and PTFE grafts with vein cuff. A precuffed graft is a reasonable alternative conduit for infragenicular reconstruction in the absence of saphenous vein and provides favorable limb salvage.Presented at the Twenty-eighth Annual Meeting of the Peripheral Vascular Surgery Society, Chicago, IL, June 7, 2003.See Appendix 1 for list of Distaflo^TM trial investigators and participating centers.     

Factors affecting the patency of infrainguinal bypass

Two hundred forty-nine well-characterized difficult distal bypasses, entered into a multicenter dextran 40 trial, were reevaluated after 3 years. Seventy in situ (IS) vein grafts, 49 reversed saphenous (RS) vein grafts, 60 polytetrafluoroethylene (PTFE) grafts, and 70 umbilical vein (UV) grafts were used. Primary and secondary patency rates at 3 years were, respectively, 84% and 90% for IS, 66% and 73% for RS, 35% and 48% for PTFE, and 24% and 32% for UV. Subgroup analysis according to the site of distal anastomosis showed no significant differences in primary patency among these grafts at the above-knee level but significant differences between both vein grafts (IS and RV) and the others (PTFE and UV) below the knee (78% vs 31%, respectively). This difference increased at the tibial level (78% vs 10%) but there was also a significant difference between IS grafts (88%) and RS grafts (63%) at this level. Hazard functional analysis showed all grafts except IS grafts begin to fail at an increasing rate again by 24 months. Although overall results appeared to favor PTFE over UV, 62% of PTFE vs 16% of UV terminated at the above-knee level and the patency results of these two grafts were not significantly different at any level. The only other factor than graft type and distal anastomotic site that consistently correlated with late patency was tobacco use. Diabetic patients actually fared significantly better than nondiabetic patients, presumably because of the higher use of IS grafts and lower use of tobacco. The choice of graft overshadows all other factors affecting patency and its influence is magnified with more distal terminal anastomosis.     

Axillopopliteal bypass for limb salvage.

Forty-one axillopopliteal bypass grafts have been placed in 30 patients for limb salvage in the past 12 years. The mean patient age was 65.6 years; 8 were women; 19 smoked; and six had diabetes. Sixteen grafts were straight axillopopliteal bypass grafts, and 25 were sequential axillopopliteal bypass grafts. Cumulative life-table primary patency rates at 1, 2, and 3 years were 70%, 56%, and 43%, respectively; secondary patency rates were 73%, 57%, and 50%, respectively. Corresponding limb salvage rates were 86%, 69%, and 69%, respectively. Ringed polytetrafluoroethylene (PTFE) graft patency at 3 years was 61% versus 40% for unsupported PTFE grafts (p = 0.35). Ringed PTFE axillofemoral grafts with sequential femoropopliteal saphenous vein grafts had a 3-year patency of 67%. Graft patency was restored in 25% of occluded grafts by thrombectomy and in 80% of occluded grafts by thrombectomy with graft revision (p = 0.21). Cumulative 3-year patient survival was 48%. The 30-day operative mortality rate was 20%; patients operated on for graft infection had a 30-day operative mortality rate of 36%. The data support the use of axillopopliteal bypass for limb salvage when standard revascularization techniques are contraindicated. Long-term patency is enhanced by use of externally supported PTFE and sequential femoropopliteal saphenous vein.     

Why small caliber vascular grafts fail: a review of clinical and experimental experience and the significance of the interaction of blood at the interface

The results using polytetrafluoroethylene (PTFE) and tanned human umbilical cord vein (HUV) grafts are discussed. These two grafts perform well for reconstructions above the knee and the results are similar to the autogenous saphenous vein (ASV) grafts in several series; however, in more distal reconstructions the PTFE and HUV are far inferior to ASV grafts. The factors responsible for graft failure including the events which take place at the blood interface are reviewed. New material surfaces under investigation such as degradable grafts, heparin-bonded surfaces, and endothelial-seeded fabrics are also addressed.     

Six-year prospective multicenter randomized comparison of autologous saphenous vein and expanded polytetrafluoroethylene grafts in infrainguinal arterial reconstructions

Autologous saphenous vein (ASV) and polytetrafluoroethylene (PTFE) grafts were compared in 845 infrainguinal bypass operations, 485 to the popliteal artery and 360 to infrapopliteal arteries. Life-table primary patency rates for randomized PTFE grafts to the popliteal artery paralleled those for randomized ASV grafts to the same level for 2 years and then became significantly different (4-year patency rate of 68% +/- 8% [SE] for ASV vs. 47% +/- 9% for PTFE, p less than 0.025). Four-year patency differences for randomized above-knee grafts were not statistically significant (61% +/- 12% for ASV vs. 38% +/- 13% for PTFE, p greater than 0.25) but were for randomized below-knee grafts (76% +/- 9% for ASV vs. 54% +/- 11% for PTFE, p less than 0.05). Four-year limb salvage rates after bypasses to the popliteal artery to control critical ischemia did not differ for the two types of randomized grafts (75% +/- 10% for ASV vs. 70% +/- 10% for PTFE, p greater than 0.25). Although primary patency rates for randomized and obligatory PTFE grafts to the popliteal artery were significantly different (p less than 0.025), 4-year limb salvage rates were not (70% +/- 10% vs. 68% +/- 20%, p greater than 0.25). Primary patency rates at 4 years for infrapopliteal bypasses with randomized ASV were significantly better than those with randomized PTFE (49% +/- 10% vs. 12% +/- 7%, p less than 0.001). Limb salvage rates at 3 1/2 years for infrapopliteal bypasses with both randomized grafts (57% +/- 10% for ASV and 61% +/- 10% for PTFE) were better than those for obligatory infrapopliteal PTFE grafts (38% +/- 11%, p less than 0.01). These results fail to support the routine preferential use of PTFE grafts for either femoropopliteal or more distal bypasses. However, this graft may be used preferentially in selected poor-risk patients for femoropopliteal bypasses, particularly those that do not cross the knee. Although every effort should be made to use ASV for infrapopliteal bypasses, a PTFE distal bypass is a better option than a primary major amputation.     

The effect of distal anastomotic site on PTFE graft patency in lower extremity bypass

The site of distal anastomosis of polytetrafluorethylene (PTFE) lower extremity bypass grafts may significantly affect results. We examined patency in 144 cases; 45 femoro-popliteal above knee (AK), 55 femoro-popliteal below the knee (BK) and 44 femoro-distal (D) PTFE bypasses, the groups being comparable with regard to other risk factors studied. Cumulative graft patency at 3 years was 71.3% for AK, 36.7% for BK, 16.4% for D and overall 35%. The site of distal anastomosis is an important determinant, of PTFE lower extremity bypass patency. We have abandoned the use of PTFE for BK and D, but feel that AK PTFE is a suitable alternative to autogenous reversed saphenous vein.     

A comparative evaluation of polytetrafluoroethylene, umbilical vein, and saphenous vein bypass grafts for femoral-popliteal above-knee revascularization: a prospective randomized Department of Veterans Affairs cooperative study

PURPOSE: Currently, the choice of a vascular prosthesis for a femoral-popliteal above-knee arterial bypass graft is left to the surgeon's preference, because the available information on comparative evaluations is inconclusive. The Department of Veterans Affairs (VA) Cooperative Study 141 was established to identify whether improved patency exists with different bypass graft materials for patients with femoral-popliteal above-knee bypass grafts. METHODS: Between June 1983 and June 1988, 752 patients at 20 VA medical centers were randomized to receive either an externally supported polytetrafluoroethylene (PTFE; N = 265), human umbilical vein (HUV; N = 261), or saphenous vein (SV; N = 226) for an above-knee femoral-popliteal bypass graft. The indication for the bypass grafting operation was limb salvage in 67.5% of the patients. Patients were observed every 3 months for the first year and every 6 months thereafter. All patients were instructed to take aspirin (650 mg) daily for the duration of the study.Doppler-derived ankle-brachial indices (ABIs) were determined preoperatively and serially postoperatively. A bypass graft was considered to be patent when the Doppler-derived postoperative ABI remained significantly improved (more than 0.15 units higher than their preoperative value) and additional objective information, such as angiograms or operations, did not contradict these observations. Patency failure also included bypass grafts that were removed because of an infection or aneurysmal degeneration. Patency rates were compared by using the Kaplan-Meier life table analysis. RESULTS: The cumulative assisted primary patency rates were statistically similar among the different conduit types at 2 years (SV, 81%; HUV, 70%; PTFE, 69%). After 5 years, above-knee SV bypass grafts had a significantly (P 相似文献