Long-term Outcome of Femoral Above-knee Popliteal Artery Bypass Using Autologous Saphenous Vein Versus Expanded Polytetrafluoroethylene Grafts

Despite a recent flurry of publications on preferred techniques for femoral above-knee popliteal artery bypass, controversy persists over the use of autologous saphenous vein and expanded polytetrafluoroethylene (ePTFE) grafts. The purpose of this study was to compare our long-term results using these two bypass materials. In a series of 474 infrainguinal bypasses performed between January 1993 and December 1998, we performed a total of 75 femoral above-knee popliteal artery bypass using an autologous saphenous vein graft in 48 cases (64%) and an ePTFE graft in 27 cases (36%). Prosthetic grafts were used by choice in 17 cases and by necessity due to the absence of useable vein in 10 cases. There were 55 men and 18 women with a mean age of 70 years. The indication for bypass was lower extremity arterial occlusive disease at stage II in 17 cases (22.7%), stage III in 9 cases (12%), and stage IV in 36 cases (48%); subacute ischemia in 8 cases (10.7%); and femoropopliteal aneurysm in 5 cases (6.7%). Preoperative arteriography demonstrated three patent leg arteries in 15.5% of cases, two patent leg arteries in 43.5%, and one patent leg artery in 41%. There was no significance difference between the vein graft and ePTFE graft groups with regard to indications and arteriographic findings. No patient died during the immediate postoperative period. The mean duration of follow-up was 25.5 months (range, 3 to 108 months). The primary patency rate at 4 years was 82.2 ± 8% for venous bypass vs. 80.6 ± 11.8% for ePTFE bypass (p = 0.42). The secondary patency rate at 4 years was 84.7 ± 7.4% for vein bypasses and 79.5 ± 12% for ePTFE bypasses (p = 0.26). In our experience, there was no statistically significant difference in long-term outcome of femoral above-knee popliteal artery bypass using autologous vein grafts or prosthetic ePTFE grafts. Presented at the Seventeenth Annual Meeting of the Société de Chirurgie Vasculaire de Langue Française, May 29-31, 2002, Liege, Belgium.     

Cuffed anastomosis for above-knee femoropopliteal bypass with a stretch expanded polytetrafluoroethylene graft

PURPOSE: To evaluate the patency and limb-salvage rates associated with cuffed anastomosis in above-knee femoropopliteal (FP) bypasses using prosthetic grafts. METHODS: Between January 1997 and December 2005, 96 patients (99 limbs) underwent above-knee FP bypass grafting for peripheral vascular disease, with disabling claudication in 81%. All grafts were 6-mm, thin-walled, ringed, expanded polytetrafluoroethylene (ePTFE) stretch grafts anastomosed to the above-knee segment of the popliteal artery in an end-to-side fashion, with a protruding area created around the anastomotic toe and an angle of less than 30 degrees between the graft and the artery. Postoperatively, graft patency was monitored by several objective methods. Patency and limb-salvage rates were calculated by actuarial methods and Kaplan-Meier analysis. RESULTS: The mean follow-up period was 40.4 months; 15 patients were lost to follow-up. The 1-, 3-, and 5-year primary graft patency rates were 94.5%, 88.2%, and 85.7%, respectively. The 1-, 3-, and 5-year secondary patency rates were 95.6%, 94.1%, and 90.8%. The 1-, 3-, and 5-year limb-salvage rates were 98.9%, 97.3%, and 97.3%. There were three graft infections. CONCLUSION: The use of a cuffed anastomosis in FP bypass with an ePTFE stretch prosthesis appears to increase graft patency rates.     

Randomized clinical trial of distal anastomotic interposition vein cuff in infrainguinal polytetrafluoroethylene bypass grafting

BACKGROUND: The aim was to examine the effect of a Miller vein cuff at the distal anastomosis on the medium- to long-term patency and limb salvage rates of femoral to above-knee and femoral to below-knee popliteal artery polytetrafluoroethylene (PTFE) bypasses. METHODS: This study involved extended follow-up of the original cohort of patients included in a previously reported multicentre randomized clinical study. Outcome measures were bypass graft patency and limb salvage. RESULTS: Two hundred and sixty-one bypass operations were originally randomized. For this study, full data were available on 235 (120 with a Miller cuff, 115 without). The cumulative 5-year patency rate for above-knee bypasses with a Miller cuff was 40 per cent, compared with 42 per cent for non-cuffed bypasses (P = 0.702). The cumulative 3-year patency rate for below-knee bypasses with a Miller cuff was 45 per cent, compared with 19 per cent for non-cuffed bypasses (P = 0.018). A Miller cuff had no significant effect on limb salvage for above-knee or below-knee bypasses. CONCLUSION: Three-year patency rates of femoral to below-knee popliteal PTFE bypasses were improved by a Miller cuff. Miller cuffs had no effect on patency rates for femoral to above-knee popliteal bypasses at 5 years and did not improve limb salvage in either group.     

Elective popliteal aneurysms: does venous availability has an impact on indications?

AIM: The aim of this retrospective study was to evaluate the patency and limb salvage rates after prosthetics or venous bypasses for asymptomatic or mildly symptomatic popliteal aneurysms, in order to determine if small uncomplicated aneurysms (caliber <300%) should be operated or periodically controlled when a venous conduit is not available. METHODS: During a 18 years period, 100 popliteal aneurysms, including 85 asymptomatic and 15 associated with intermittent claudication, were operated on: group I consisted of 80 venous bypasses, and group II consisted of 20 prosthetic bypasses. RESULTS: Demographics and risks factors were similar in both groups. Local complications were more frequent in group I (17% vs 10% p=NS). Early vascular complications were rare in both groups. Late arterial complications were more frequent in group II. Primary patency, assisted primary patency, and secondary patency rates at 2 years were 94.3%, 97.3% and 98.7% in group I, and 61.5%, 89% and 88.4% in group II (p<0.05). In contrast, the limbs salvage rates were not significantly different for each type of graft (98.7% vs 100% p=NS). CONCLUSIONS: Our data shows that aneurysms treated with a prosthetic graft are at higher risk of late occlusion than those operated with a vein graft. This should be taken into account when facing a small uncomplicated aneurysm without available venous conduit. The presence of a suitable vein should be checked before deciding to operate a small uncomplicated popliteal aneurysm.     

Operative Repair of Popliteal Aneurysms: Effect of Factors Related to the Bypass Procedure on Outcome

The objective of this study was to compare patency rates following the repair of popliteal aneurysms according to the site of inflow, material of bypass graft and quality of distal runoff. Seventy bypasses were performed over an 11-year period. Autogenous saphenous vein was used in 53 procedures (75.7%) and prosthetic material was used in 17 (24.3%). Early mortality was 2.8%. Early primary and secondary patency rates were 95.7% and 97.1%, respectively. Autogenous vein showed better 10-year patency than prosthetic material (86% vs. 57%; p = 0.02). No significant differences in patency were observed according to the inflow site (87.8% groin vs. 74.7% supragenicular). Bypasses that originated in the groin showed improved patency when a saphenous vein was used (84.8% vs. 43.7%; p = 0.01). However, no influence of the graft material was noted in supragenicular bypasses (90.4% vs. 84.8%; p = 0.6). Bypasses in extremities with good runoff showed better patency than those in limbs showing poor runoff (86% vs. 55%; p = 0.003). The use of saphenous vein for the repair of popliteal aneurysms showed better results than those with prosthetic material, although in bypasses originating from the distal superficial femoral or above-knee popliteal artery, no significant differences in patency were observed. Good distal runoff was associated with improved overall outcome.     

Long-term results of infragenicular bypasses with autogenous vein originating from the distal superficial femoral and popliteal arteries

Forty-nine bypasses originating from the distal superficial femoral artery or popliteal artery in 46 patients were reviewed to examine late patency, limb salvage, and factors leading to graft failure. Operations were performed because of tissue loss in 86%, rest pain in 12%, and limiting claudication in 2% of limbs. Proximal anastomosis was from the distal superficial femoral artery in 12% and the popliteal artery in 88%. Distal anastomosis was to the below-knee popliteal artery or proximal tibial vessels in 20% and the distal tibial vessels in 80%. Life-table analysis showed a primary patency rate of 83%, 62%, and 41%, at 1, 3, and 5 years, respectively. The rate of limb salvage at 6 years for all grafts was 69%. Cox proportional hazards analysis determined that stenosis of 20% or greater in the proximal superficial femoral artery before bypass was a significant risk factor for graft failure (p = 0.02) despite the presence of normal intra-arterial pressure at the site of the proximal anastomosis at the time of bypass. Long-term survival in these patients was low, with a 6-year survival rate of only 24%. Infragenicular bypasses originating from the distal superficial femoral artery or the popliteal artery can be performed with patency and limb salvage rates comparable to bypasses originating from the common femoral artery. These bypasses are more likely to fail when performed in the presence of a stenosis 20% or greater in the superficial femoral or popliteal artery proximal to the graft origin.     

Nature and management of duplex abnormalities encountered during infrainguinal vein bypass grafting

Purpose: This study was undertaken to evaluate the application of duplex scanning during infrainguinal vein grafting procedures to verify vein conduit preparation, anastomotic patency, and graft hemodynamics.Methods: Between 1991 and 1995, 275 infrainguinal vein bypasses (in situ, 114; reversed, 82; nonreversed translocated, 48; spliced alternative/arm vein, 31) to the popliteal (n = 116) or an infrageniculate artery (n = 159) were scanned during surgery for sites of color Doppler flow abnormality. Duplex-detected defects were graded with peak systolic velocity and velocity ratio criteria. Sites that demonstrated highly disturbed flow (peak systolic velocity >180 cm/sec, velocity ratio >2.4) were immediately revised by direct repair, patch angioplasty, or interposition grafting.Results: Intraoperative duplex scanning prompted revision of 50 abnormalities in 43 of the 275 grafts (16%), including 32 vein and seven anastomotic stenoses, nine vein segments with platelet thrombus, and two bypasses with low flow. The intraoperative revision rate was lowest (p < 0.02) for reversed saphenous vein bypasses (7%) compared with other grafting techniques (in situ, 20%; nonreversed translocated, 15%; spliced alternative vein, 23%). The revision rates of popliteal and tibial bypasses were similar (14% vs 17%). A normal result shown by intraoperative scan (235 bypasses) was associated with a low 90-day thrombosis (0.4%) and revision (2%) rate, whereas six of 15 grafts (40%) with residual and 13 of 25 grafts (52%) with unrepaired duplex abnormalities required corrective procedures (p < 0.001). One graft failed within 3 months (secondary patency rate, 99%).Conclusions: Intraoperative duplex scanning accurately predicted the technical adequacy of infrainguinal vein grafts and was particularly useful in assessing bypasses constructed with valve lysis techniques or alternative veins. Early graft revisions indicated by duplex monitoring for thrombosis or stenosis were the result of a progression of residual defects and platelet thrombus formation rather than inadequate graft run-off flow. (J Vasc Surg 1996;24:430-8.)     

Sutureless nonocclusive bypass surgery in combination with an expanded polytetrafluoroethylene graft. Laboratory investigation

OBJECT: Cerebral aneurysms that cannot be treated by clip or coil placement can be treated with high-flow bypass surgery using techniques such as the excimer laser-assisted nonocclusive anastomosis (ELANA). To simplify the technique, a sutureless ELANA (SELANA) was developed in combination with an expanded polytetrafluoroethylene (ePTFE) graft. METHODS: In 18 rabbits a bypass was constructed on the abdominal aorta using the SELANA technique with an ePTFE graft, resulting in 18 bypasses and 36 anastomoses. Short-term effects were analyzed in the first 2 weeks and at 2 and 3 months after the procedure. Patency was evaluated using quantitative ultrasound flowmetry. The anastomotic sites were studied using scanning electron microscopy. RESULTS: Construction of the bypass using the SELANA technique was easier and faster (15-25 minutes) compared with bypasses made with the ELANA technique (> 90 minutes). At the end of follow-up, 16 of 18 bypasses were patent. Of 36 SELANA anastomoses, 32 could be completed without short temporary occlusion of the recipient vessel. Scanning electron microscopy showed complete coverage of all anastomoses with neointimal repair tissue after 10 days. CONCLUSIONS: The SELANA technique provides further advantages over the conventional ELANA technique in ease of use and shortening of procedure time. The patency rate in this series was 89% and neointima repair tissue at the anastomosis site was complete after 10 days. Further experimental studies of the long-term patency and safety of this technique are necessary before clinical application.     

Impact of Cuffed, Expanded Polytetrafluoroethylene Dialysis Grafts on Graft Outlet Stenosis

Background The objective of this study was to determine prospectively the difference between the graft outlet strictures of a polytetrafluoroethylene (ePTFE) graft with a cuff at the graft-vein anastomosis (Venaflo; Bard industries, Tempe, Ariz.) and that of the regular ePTFE graft (Stretch Gore-Tex; Gore, Flagstaff, Ariz.) placed for hemodialysis access. Methods Between January and April 2005, 36 consecutive patients (average age: 63.3 years) underwent ePTFE graft implantation (36 implantations) for hemodialysis at the Vascular Surgery Section of Chang Gung Memorial Hospital. The patients of the study cohort were randomly assigned to two groups based on the graft used: cuffed graft group (Venaflo graft) and non-cuffed standard graft group (Gore-Tex graft). Each patient underwent antegrade venography at the 3-month follow-up to demonstrate the graft outlet stricture. Results of the graft outlet angiography analysis were examined, and all medical records were reviewed at end of the study. The degree of the graft outlet stenosis was compared between the two groups. Results Average stenosis of the cuffed graft group and non-cuffed (standard) graft group were 22.76 ± 26.37%% and 44.95 ± 27.48%%, respectively; the difference between the two groups was statistically significant (P < 0.05). Conclusions The graft outlet stricture of cuffed ePTFE grafts for hemodialysis 3 months after implantation was less severe than that for the standard ePTFE graft. The correlation between the stricture level and dialysis graft patency requires further clarification.     

Comparison of Precuffed and Vein-Cuffed Expanded Polytetrafluoroethylene Grafts for Infragenicular Arterial Reconstructions:A Case-Matched Study

Distal vein cuff interposition is often added to prosthetic infragenicular arterial reconstruction in an attempt to improve hemodynamics and patency rates. The purpose of this study was to compare the outcome of a precuffed expanded polytetrafluroethylene (ePTFE) graft with a vein-cuffed ePTFE graft for infragenicular bypass. We reviewed the clinical outcome of 77 patients with critical limb ischemia without available autologous vein conduits who underwent arterial reconstruction of 80 limbs to below-knee popliteal or tibioperoneal vessels using either ePTFE precuffed graft (precuffed group, 38 patients 40 limbs) or ePTFE vein-cuffed graft (vein-cuffed group, 39 patient, 40 limbs). Precuffed group patients were enrolled in a prospective cohort study. Vein-cuffed group patients consisted of consecutive case-matched patients operated on during the same study period. End points were primary graft patency and limb salvage rates. There were 42 males and 35 females with a mean age of 73.4 years (range, 44-92 years). Both groups were matched to demographics, risk factors for atherosclerosis, previous ipsilateral reconstruction, and location of the distal anastomosis. Proximal anastomosis was to the common (n=68) or superficial (n=12) femoral arteries. Distal anastomosis was to the below-knee popliteal (n=28), anterior tibial (n=12), posterior tibial (n=15) and peroneal (n=25) arteries. Operative mortality was 1.3%. Graft patency at dismissal was 90% and 95% in the precuffed and vein-cuffed groups, respectively. The mean follow-up was 25.7 months (range, 2.4-61 months). Primary patency rates at 1 and 3 years were 70% and 57% in the precuffed group, and 78% and 54% in the vein-cuffed group (p=0.32). Limb salvage rates at 1 and 3 years were 97% and 70% in the precuffed group, and 95% and 81 % in the vein-cuffed group (p=0.49). Overall patient survival at 1 and 3 years was 81 % and 57%, respectively. In this case-control study, results of precuffed ePTFE graft were similar to those obtained with vein-cuffed ePTFE grafts. The precuffed ePTFE graft is an adequate alternative conduit for infragenicular arterial reconstruction in patients with critical limb ischemia and no available autologous veins.Presented at the 32^nd Annual Symposium on Vascular Surgery, Society for Clinical Vascular Surgery, Rancho Mirage, CA, March 10–13, 2004.     

Randomized comparison of percutaneous Viabahn stent grafts vs prosthetic femoral-popliteal bypass in the treatment of superficial femoral arterial occlusive disease

OBJECTIVE: This randomized prospective study was designed to compare the effectiveness of treating superficial femoral artery occlusive disease percutaneously with expanded polytetrafluoroethylene (ePTFE)/nitinol self-expanding stent grafts vs surgical femoral-to-above knee (AK) popliteal artery bypass with synthetic graft material. METHODS: From March 2004 to May 2005, 100 limbs in 86 patients with femoral-popliteal arterial occlusive disease were identified. Patients had symptoms ranging from claudication to rest pain, with or without tissue loss, and were prospectively randomized for treatment into one of two groups. The limbs were treated percutaneously with angioplasty and one or more self-expanding stent grafts (n = 50) or surgically with femoral-to-AK popliteal artery bypass using synthetic Dacron or ePTFE grafts (n = 50). The mean +/- SD total length of artery stented was 25.6 +/- 15 cm. Follow-up evaluation with ankle-brachial indices and color flow duplex sonography imaging were performed at 3, 6, 9, and 12 months after treatment. RESULTS: Patients were monitored for a median of 18 months. No statistical difference was found in the primary patency (P = .895) or secondary patency (P = .861) between the two treatment groups. Primary patency at 3, 6, 9, and 12 months of follow-up was 84%, 82%, 75.6%, and 73.5% for the stent graft group and 90%, 81.8%, 79.7%, and 74.2% for the femoral-popliteal surgical group. Thirteen patients in the stent graft group had 14 reinterventions, and 12 reinterventions occurred in the surgical group. This resulted in secondary patency rates of 83.9% for the stent graft group and 83.7% for the surgical group at the 12-month follow-up. CONCLUSIONS: Management of femoral-popliteal arterial occlusive disease using percutaneous treatment with a stent graft is comparable with surgical revascularization with conventional femoral-to-AK popliteal artery bypass using synthetic material up to 12 months. Longer-term follow-up would be helpful in determining ongoing efficacy.     

Analysis of factors influencing patency of polytetrafluoroethylene prostheses for limb salvage

This clinical review of 70 polytetrafluoroethylene femoropopliteal and femoral-distal (tibial or peroneal) bypasses for limb salvage analyzes factors that influence graft patency. Patients with “good” angiographic run-off (n = 26) had a significantly better (P < 0.01) cumulative patency rate when compared to patients with “poor” (n = 43) angiographic run-off. Other factors which had a significant influence on graft patency over the 2-year follow-up included site of distal anastomosis (femoropopliteal versus femoral-distal), and previously failed femoropopliteal bypass. Patients with a preoperative ankle/brachial Doppler pressure index of less than 0.2 had a 67% occlusion rate during the first postoperative month. Thrombectomy and distal revisions (patch or jump graft) following graft occlusion did not significantly prolong graft patency.     

Lower limb revascularization with a new bioactive prosthetic graft: early and late results

The aim of the study was to evaluate the immediate and long-term results of femoropopliteal bypasses performed with a new bioactive heparin-treated expanded polytetrafluoroethylene (ePTFE) graft in a single-center experience. From March 2002 to April 2006, 51 patients underwent lower limb revascularization with a new bioactive ePTFE prosthetic graft with covalent end-point attachment of heparin to the graft surface. Data concerning preoperative assessment, intraoperative strategy, drug administration, and follow-up surveillance program were prospectively collected in a dedicated database; early results were analyzed in terms of graft patency, amputation rate, and deaths. Follow-up consisted of clinical and duplex scan examination at 1, 6, and 12 months and yearly thereafter. Midterm results in terms of primary and secondary patency, limb salvage, and survival were analyzed. Patients were predominantly male (35 patients, 71%), with a mean age of 71 years (SD = 9.05). Indications for surgical revascularization were critical limb ischemia in 36 patients and severe intermittent claudication in 15 patients. Interventions were performed for occlusion of a native vessel in 35 cases, whereas 12 patients had late thrombosis of a femoropopliteal bypass; the remaining four patients were operated on for an occluded popliteal artery aneurysm. Intervention consisted of below-knee bypass in 34 patients, while the other 17 had an above-knee revascularization. No perioperative deaths occurred. Cumulative 30-day graft patency was 88%, with an amputation rate of 4% (two cases). Results were similar in above- and below-knee revascularizatons. Mean duration of follow-up was 18 months (SD = 7). Cumulative estimated 24-month survival and primary patency rates were 97% and 80.2%, respectively; the corresponding limb salvage rate was 85.7%. Long-term results did not significantly differ in above- and below-knee revascularizatons. In our experience, the use of a modified ePTFE graft with covalent end-point linkage of heparin molecules on the graft surface provides good early and midterm results, with low rates of graft thrombosis and amputation.     

Prospective,randomized evaluation of a cuffed expanded polytetrafluoroethylene graft for hemodialysis vascular access

BACKGROUND: A cuffed expanded polytetrafluoroethylene (ePTFE) hemodialysis graft was developed to address the problem of recurrent stenosis at the graft-vein anastomosis. The purpose of this study was to compare graft patency and blood flow rates of cuffed and noncuffed (standard) ePTFE grafts placed for hemodialysis access. METHODS: Forty-eight patients were prospectively randomized and followed for up to 24 months after placement of a cuffed or standard ePTFE graft for hemodialysis access. Study end points included time to graft failure and blood flow rates on hemodialysis. RESULTS: Risk factors for graft failure were similar in both groups. However, the overall incidence of graft failure was significantly lower in the cuffed ePTFE graft group (P =.039). Graft patency rates in the cuffed versus standard groups were 64% versus 32% at 12 months (P =.037) and 58% versus 21% at 24 months (P =.0213). No cuffed ePTFE graft failed as a result of venous outflow stenosis. Average graft flow rates were similar when first measured 3 months postoperatively (845 mL/min, cuffed vs 715 mL/min, standard; P =.51) but declined more rapidly in the standard group (12 months, 623 vs 253 mL/min [P =.037]; 24 months, 531 vs 121 mL/min [P =.012]). CONCLUSIONS: The cuffed ePTFE graft was associated with increased blood flow rates during hemodialysis and improved graft patency compared with a standard ePTFE graft. Our results suggest a beneficial effect of the cuffed venous geometry for hemodialysis vascular access.     

Autologous saphenous vein and heparin-bonded expanded polytetrafluoroethylene as graft materials for below-the-knee femoro-popliteal bypass in patients with critical limb ischemia: A propensity score-matched analysis

ObjectiveTo compare the outcomes of heparin bonded expanded polytetrafluoroethylene (HePTFE) and autologous saphenous vein (ASV) in patients undergoing below-knee (BK) femoro-popliteal bypass for critical limb ischemia (CLI).DesignRetrospective single-centre matched case–control study.MethodsFrom 2003 to 2019, 275 consecutive BK bypasses for CLI were performed, 109 with the ASV and 166 with a HePTFE graft. All the baseline characteristics that were reliably measured and were potentially relevant in the decision-making process were included as confounders in a logistic regression model and the factors that were significantly different between the two groups then used to perform a propensity matching analysis. Propensity score-based matching was performed in a 1:1 ratio to compare outcomes. Arterial hypertension, hyperlipemia, the need for tibial anastomosis at the distal level and the run-off status were the covariates included in the matching. Follow-up outcomes were estimated by Kaplan–Meier methods and compared with log rank test.ResultsAfter propensity matching, 101 HePTFE bypasses were matched with 101 ASV bypasses. The median duration of follow-up was 37 months (range 1–192). The 5-year survival rate was 67.5% (standard error (SE) 0.05) in the HePTFe group and 64.5% (SE 0.06) in the ASV group (p = 0.8, log rank 0.04). Primary patency rates were 38% (SE 0.06) in the HePTFE group and 41% (SE 0.06) in the ASV group (p = 0.7, log rank 0.3). Also assisted primary patency and secondary patency rates did not differ in the two groups. Amputation-free survival was 53% (SE 0.05) in the HePTFE group and 58% (SE 0.06) in the ASF group (p = 0.6, log rank 0.2).ConclusionsHePTFE provided 5-year similar results to those obtained with use of the ASV in equivalent patients with CLI undergoing below-knee or tibial bypass.     

Endovascular Stent-Grafts for Aneurysms of the Femoral and Popliteal Arteries

n = 2); a true aneurysm of the popliteal artery (n= 4); an aneurysmal dilatation of a Biograft bypass (n= 2); a false aneurysm of the superficial femoral aneurysm (n= 1); and a false aneurysm of a composite bypass (n= 1). In 8 of the 10 patients the stent-graft was composed of one or more Palmaz stents sutured to an ePTFE tube graft; in the other 2 patients a venous covering was used in combination with Palmaz stents. The procedure was guided by angiography and intravascular ultrasound. The results of our investigation showed that endovascular stent-grafting of aneurysms of the femoropopliteal artery is a feasible but experimental technique that should be restricted to a selected group of patients.     

Prospective randomised trial of distal arteriovenous fistula as an adjunct to femoro-infrapopliteal PTFE bypass.

OBJECTIVES: To compare graft patency and limb salvage rate following femoro-infrapopliteal bypass using ePTFE grafts with and without the addition of adjuvant arterio-venous fistula. DESIGN: A prospectively randomised controlled trial. MATERIALS: Patients referred to two teaching hospital vascular surgery units in the U.K. for the treatment of critical limb ischaemia. METHODS: Eighty-seven patients (M:F; 2.3:1) undergoing 89 femoro-intrapopliteal bypass operations with ePTFE grafts for critical limb ischaemia were randomly allocated to have AVF included in the operative procedure (n = 48) or to a control group without AVF (n = 41). An interposition vein-cuff was incorporated at the distal anastomosis in all patients. RESULTS: The cumulative rates of primary patency and limb salvage at 1-year after operation for patients with AVF were 55.2% and 54.1% compared to 53.4% and 43.2%, respectively, for the control group. The differences between the AVF and control groups did not reach statistical significance, in terms of either graft patency or limb salvage, at any stage after operation (Log-Rank test). CONCLUSIONS: AVF confers no additional significant clinical advantage over interposition vein cuff in patients having femoro-infrapopliteal bypass with ePTFE grants for critical limb ischaemia.     

Endothelial seeding of polytetrafluoroethylene femoral popliteal bypasses: The failure of low-density seeding to improve patency

Purpose: We compared 66 seeded polytetrafluoroethylene and 53 autologous vein grafts to determine whether endothelial seeding could improve the patency of polytetrafluoroethylene femoral popliteal bypass grafts and to determine whether endothelial seeding could be performed consistently in multiple institutions. Methods: Nine surgeons at four hospitals randomized patients to receive either a seeded polytetrafluoroethylene or a vein graft, but if no satisfactory vein (n = 26) existed, an "obligatory" seeded polytetrafluoroethylene graft was used. Results: Scanning electron microscopy confirmed satisfactory initial attachment of endothelium on the discarded ends of the grafts. Patency was compared with the use of log rank analysis and revealed better patency in vein grafts at 30 months (vein = 91.6% ± 4.1%; seeded polytetrafluoroethylene = 37.8% ± 9.4%; p = 0.006). Failed grafts revealed anastomotic hyperplasia. Conclusions: (1) Vein graft patency was better than seeded polytetrafluoroethylene grafts; (2) seeding did not improve patency in below-the-knee bypasses as suggested by pilot studies; (3) the failure of seeded grafts was associated with anastomotic hyperplasia but not with the failure of initial endothelial attachment; and (4) each institution reported similar results. (J VASC SURG 1994;20:650-5.)     

Intensive surveillance of femoropopliteal-tibial autogenous vein bypasses improves long-term graft patency and limb salvage.

OBJECTIVE: The authors determined the impact of an intensive surveillance program of autogenous vein bypasses on patency and limb salvage. SUMMARY BACKGROUND DATA: Surveillance protocols of vein bypasses can identify graft-threatening lesions to permit elective revisions before thrombosis. The authors compared follow-up based on clinically indicated procedures with intensive surveillance. METHODS: From 1985 to 1994, 615 autogenous vein bypasses (454 in situ, 161 reversed/composite) to popliteal (n = 169) and tibial (n = 446) arteries were performed for critical limb ischemia (n = 507), claudication (n = 88), and popliteal aneurysm (n = 20). Intensive surveillance of autogenous vein bypasses consisted of ankle brachial index and duplex scan with graft velocities measured at 1 month, 3 months, 6 months, and every 6 months subsequently. After surgery 317 bypasses had intensive surveillance, 222 bypasses were clinically indicated for follow-up, and 76 bypasses were excluded because follow-up or patency was less than 31 days. RESULTS: Primary patency at 5 years was similar for bypasses treated by intensive surveillance (56%) and those treated with clinically indicated procedures (67%). Secondary patency and limb salvage at 5 years was significantly improved (p < 0.02) for bypasses followed by intensive surveillance (80% and 94%) compared with clinically indicated procedures (67% and 73%). Revision of patent bypasses was higher (p < 0.000001) for bypasses treated by intensive surveillance (61 of 70, 87%) compared with those treated with clinically indicated procedures (9 of 34, 26%). Secondary patency at 2 years was significantly higher (p < 0.02) for revision of patent bypasses (79%) compared with thrombosed bypasses (55%). CONCLUSIONS: Long-term autogenous vein bypass patency and limb salvage is significantly improved by intensive surveillance, permitting identification and correction of graft threatening lesions before thrombosis.     

Evaluation of Neointimal Hyperplasia on Tranilast-Coated Synthetic Vascular Grafts: An Experimental Study

Tranilast is an antiallergic drug that interferes with proliferation and migration of vascular smooth muscle cell induced by platelet-derived growth factor (PDGF) and transforming growth factor-β1 (TGF-β1). We investigated the local effect of tranilast on neointimal hyperplasia using tranilast-coated prosthetic grafts. The inner sides of the thin-walled polytetrafluoroethylene (PTFE) grafts were coated with chitosan and tranilast containing chitosan solution. Wistar albino rats (32) were used in the study. Patches (1 × 2 mm) for vascular grafts were prepared. Three groups were tested: group 1 (n = 12; tranilast coated), group 2 (n = 10; adhesive-only film-layer–coated), and group 3 (n = 10; normal ePTFE patch grafts sutured to the carotid arteries of the rats). Recipient sites of the carotid arteries were excised 4 weeks after surgery. All sections were examined histologically for graft patency, thrombus formation, and neointimal thickness. Expression of PDGF, fibroblast growth factor, and TGF-β1 on cross-sections of the neointima were evaluated by immunohistochemistry. No significant differences were found regarding mean neointimal thicknesses. PDGF and TGF-β-1 expressions were significantly lower in group 1. Although a decrease in local effect of tranilast was observed for growth factor expressions at a drug concentration of 0.05 mg/cm², a significant reduction in neointimal hyperplasia was not achieved. The coating concentration of 0.05 mg/cm² may have been too low to produce an antiproliferative effect. Given our promising results, further studies are recommended and planned using different drug concentrations and time intervals.