Patency Rates and Complications of Exxcel Yarn-Wrapped Polytetrafluoroethylene Grafts Versus Gore-Tex Stretch Polytetrafluoroethylene Grafts: A Prospective Study

Purpose. Polytetrafluoroethylene (PTFE) has long been used for hemodialysis access when there is no suitable superficial vein. We conducted a prospective randomized study to compare two PTFE grafts; the stretch Gore-tex graft and the Exxcel graft.Methods. Between May 2000 and February 2001, PTFE grafts were implanted for hemodialysis access in the upper extremities of 94 consecutive patients with end-stage renal disease. Graft selection was randomized, with patients receiving either a Gore-tex or an Exxcel graft. All grafts were monitored for signs of thrombosis or other complications. Graft survival was analyzed using a life-table analysis and the log-rank test was applied to compare graft patency.Results. The primary patency rates 1 and 2 years after implantation were 51% and 36% for the Exxcel grafts, and 71% and 45% for the Gore-tex grafts, respectively. The difference between the two groups was not significant at any time. The incidence of complications needing further surgical management was 8.2% in the Exxcel group and 6.7% in the Gore-tex group, without a significant difference.Conclusion. Exxcel grafts or Gore-tex stretch grafts can be used for dialysis access with similar expected outcomes for up to 2 years, despite the differences in their outer surface design. The yarn-wrapped design does not appear to enhance the graft patency and we found no remarkable difference.     

Long-term patency rates, complications and cost-effectiveness of polytetrafluoroethylene (PTFE) grafts for hemodialysis access: a prospective study that compares Impra versus Gore-tex grafts.

Manufacturers of polytetraflouroethylene (PTFE) grafts used for chronic hemodialysis access describe specific advantages for their respective grafts, which presumably result in greater graft patency rates, reduced complications and decreased overall costs. There are few data available in the literature to support or contradict these alleged benefits. Therefore, this prospective study was undertaken to evaluate and compare patency rates, complications and costs between two of the leading brands of PTFE that are currently being marketed for use as hemodialysis access grafts. Totals of 190 primary PTFE grafts (100 Gore-tex (W. L. Gore and Associates, Flagstaff, AZ) and 90 Impra (C. R. Bard Inc., Tempe, AZ)) were implanted in 168 consecutive patients with end-stage renal disease. A policy of non-interventions was employed for patent grafts, as no attempt was made to assist primary patency. Grafts that occluded during follow-up underwent secondary revision to maintain patency. There was no difference in primary and secondary patency by life-table analysis between Gore-tex and Impra grafts at 2 years (P > 0.53 and P > 0.13, respectively). There was also no significant difference between Gore-tex and Impra in the number of days before the first thrombectomy or in the number of thrombectomies or revisions per graft (P > O.50). Likewise, the incidence of complications was similar between the two grafts. The cost of graft implantation and maintenance of patency was not significantly different between Gore-tex and Impra grafts. It is concluded that either graft can be used for hemodialysis access with similar expected outcomes for at least 2 years following implantation.     

The expanded polytetrafluoroethylene graft. Three years' experience with 362 grafts.

A total of 362 polytetrafluoroethylene (PTFE) grafts were implanted in patients as vascular substitutes in a variety of vascular reconstructive procedures. A total of 184 were used in femoropopliteal bypass operations. Cumulative patency rates showed 74% patency at the end of the first year of observation and 58% after two and three years. Seventeen grafts were used for femorotibial bypasses, with a cumulative patency rate of 40.4% after one year. Ninety-eight grafts were implanted in the upper or lower extremity to serve as vascular access for hemodialysis. For this group, the cumulative one-year patency rate was 83%. Sixty-three additional grafts were implanted in various other anatomic locations. Based on this experience, the PTFE graft seems to be a promising and versatile vascular prosthesis, although it should be used cautiously.     

Reduction of Vascular Intimal-Medial Hyperplasia in Polytetrafluoroethylene Arteriovenous Grafts via Expression of an Inhibitor of G Protein Signaling

Polytetrafluoroethylene (PTFE) arteriovenous (AV) grafts are performed routinely for vascular access. The limited life span of PTFE grafts is a major cause of morbidity. Graft failure is attributed to venous outflow tract vascular smooth muscle (VSM) hyperplasia, which is linked to heterotrimeric G protein signaling. We proposed that expression of a peptide inhibitor of G_βγ signaling (βARKct) in the venous outflow of PTFE grafts would reduce hyperplasia and prolong graft patency. Left carotid to right external jugular vein PTFE AV grafts were placed in swine. The isolated external jugular vein was treated with an adenovirus encoding βARKct, empty adenovirus, or phosphate-buffered saline for approximately 25 min. After 7 or 28 days, flow probe analysis was performed and the vein was harvested and analyzed for cross-sectional area comparison. After both 7 and 28 days, when compared to controls, treated animals demonstrated a statistically significant reduction in VSM hyperplasia with a reduction in cross-sectional intimal and medial areas of >40% (p < 0.05). Flow was maintained in treated grafts, while control groups demonstrated a >50% reduction (p < 0.05) at 7 days. Further, treated grafts demonstrated significant improvement in graft patency at 28 days (100% vs. 12% for treated and untreated grafts, respectively). The inhibition of G_βγ signaling reduces intimal-medial hyperplasia and prolongs graft patency in PTFE AV grafts. This represents a novel molecular therapeutic strategy for improving the patency of vascular access grafts.Part of this work was presented at the American Heart Association Annual Meeting, Chicago, IL, September 2002.     

A single center experience in the use of polyurethaneurea arteriovenous grafts

BACKGROUND: Polytetrafluoroethylene (PTFE) grafts often require temporary catheters, which increase costs as well as risk of infection, bleeding, and poor blood flow. Polyurethaneurea (PUU) grafts can be cannulated within 24 hours of placement, avoiding the need for temporary catheters. METHODS: Hemodialysis patients who were not candidates for arteriovenous fistula (AVF) were eligible for the study. Those requiring urgent (<48 hours) hemodialysis access received PUU grafts; all others received PTFE grafts. One surgeon performed all implantations. RESULTS: 133 PUU grafts were implanted, 31 (24%) patients died (unrelated to graft placement). Within the first 4 days after graft placement, 108 of 133 grafts (81%) were cannulated. None required a temporary catheter. Of 102 surviving patients, 50 (49%) had graft thrombosis; 47/50 (94%) underwent successful percutaneous thrombectomy (PT). Primary patency at 6 months and at 1 year was 51% and 33%, respectively. Secondary patency at 6 months and 1 year was 78% and 61%, respectively. Mean bleeding time (after withdrawal of dialysis needle) was 4.0 (range 1-14) minutes in PUU grafts vs. 9.2 (1-30) minutes in PTFE grafts. CONCLUSIONS: Polyurethane graft placement allowed early graft cannulation without temporary catheters. Patency rates are comparable with previous reports. Decreased bleeding time with PUU grafts reduced aggregate blood exposure for patients and staff, lowering the risk of infection and anemia exacerbation and speeding time between treatments.     

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.     

Long-term complication and patency rates of Vectra and IMPRA Carboflo vascular access grafts with aggressive monitoring, surveillance and endovascular management

The purpose of this study is to compare infection, pseudoaneurysm formation and patency rates during long-term follow-up of polyurethane and polytetrafluoroethylene (PTFE) vascular access grafts maintained with contemporary endovascular methods. During a 34-month period, 239 polyurethane and 125 carbon-impregnated PTFE vascular access grafts were placed in 324 consecutive patients. Thirty-six patients (9.9%) developed a pseudoaneurysm (anastomotic, n = 6 or at the needle-stick site, n = 30). An additional 19 patients (5.2%) required graft excision for infection. Three-year graft infection and pseudoaneurysm formation (at needle-stick site) rates were similar in polyurethane and PTFE grafts (11% versus 8%, P = 0.61, and 17% versus 23%, P = 0.72, respectively). Three-year secondary patency was better in polyurethane than PTFE grafts (69% versus 57%, respectively, P = 0.012). Straight upper arm polyurethane grafts had the best secondary patency (P = 0.001). Contemporary long-term secondary patency of vascular access grafts is satisfactory. Further follow-up is necessary to compare late infection and pseudoaneurysm formation rates.     

Usability of ringed polytetrafluoroethylene grafts for middle hepatic vein reconstruction during living donor liver transplantation

Large vein allografts are suitable for middle hepatic vein (MHV) reconstruction, but their supply is often limited. Although polytetrafluoroethylene (PTFE) grafts are unlimitedly available, their long-term patency is relatively poor. We intended to enhance the clinical usability of PTFE grafts for MHV reconstruction during living donor liver transplantation (LDLT). Two sequential studies were performed. First, PTFE grafts were implanted as inferior vena cava replacements into dogs. Second, in a 1-year prospective clinical trial of 262 adults undergoing LDLT with a modified right lobe, MHV reconstruction with PTFE grafts was compared with other types of reconstruction, and the outcomes were evaluated. In the animal study, PTFE grafts induced strong inflammatory reactions and luminal thrombus formation, but the endothelial lining was well developed. In the clinical study, the reconstruction techniques were revised to make a composite PTFE graft with an artery patch on the basis of the results of the animal study. MHVs were reconstructed with cryopreserved iliac veins (n = 122), iliac arteries (n = 43), aortas (n = 13), and PTFE (n = 84), and these reconstructions yielded 6-month patency rates of 75.3%, 35.2%, 92.3%, and 76.6%, respectively. The overall 6-month patency rates for the iliac vein and PTFE grafts were similar (P = 0.92), but the 6-month patency rates with vein segment 5 were 51.0% and 34.7%, respectively (P = 0.001). The overall graft and patient survival rates did not differ among these 4 groups. In conclusion, ringed PTFE grafts combined with small vessel patches showed high patency rates comparable to those of iliac vein grafts; thus, they can be used for MHV reconstruction when other sizable vessel allografts are not available.     

Experience with Cryopreserved Cadaveric Femoral Vein Allografts Used for Hemodialysis Access

The purpose of this study was to review the patency and complications of cryopreserved vein allografts used for hemodialysis access, and to compare them to a group with polytetrafluoroethylene (PTFE) grafts. Patients without adequate vasculature for native fistula were implanted with vein allografts or PTFE grafts at the surgeons discretion. Only cryopreserved (CRY) veins were used until January 2001, when decellularized, cryopreserved Synergraft (SYN) veins became available. The CRY group had 48 patients; the SYN group, 42 patients; the PTFE group, 100 patients, who were selected from billing records listing PTFE graft insertion. Patient demographics were similar. Primary and secondary patencies were not significantly different at 1 or 2 years between groups. Complications in PTFE versus CRY and SYN groups were as follows: infection, 10 % vs. 0% (p < 0.01); aneurysm, 2% vs. 18% (p < 0.001); and steal syndrome, 12% vs. 12% (p = NS). Significantly more vein allograft patients lost their accesses to aneurysm (p < 0.01) and multiple stenoses (p < 0.05), whereas PTFE patients lost significantly more accesses to infection (p < 0.01) and recurrent thrombosis (p < 0.05). We conclude that cadaver vein allografts have similar patency to PTFE grafts. These allografts are more resistant to infection but significantly more susceptible to aneurysms. When used, vein allografts should be monitored aggressively for the development of aneurysms.Abstract presented at the 84th Annual Meeting of the New England Surgical Society, Newport, RI, September 19, 2003, and American Society of Nephrology 36th Annual Meeting, San Diego, CA, November 12, 2003.     

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.     

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.     

Haemodialysis dose is independent of type of surgically-created vascular access

Background: In the United States, the use of polytetraflourotheylene (PTFE) graft compared with native arteriovenous fistula (AVF) for haemodialysis vascular access has been increasing despite a greater than two-fold higher incidence of thrombosis and infection associated with PTFE grafts. Methods: We studied 214 haemodialysis patients with not more than two revisions of their vascular access, to determine whether any relationship exists between the type of haemodialysis vascular access and dialysis dose assessed primarily by urea reduction ratio (per cent reduction in blood urea nitrogen concentration after a dialysis session). Serum albumin concentration was used as a secondary outcome measure of dialysis adequacy. Urea reduction ratio and predialysis serum albumin concentration were measured at onset of study and at 4-week intervals and mean values were calculated for each subject. Results: The 214 patients (118 males, 96 females) included 173 Blacks (81%), 26 Whites (15%), and 15 Hispanics (7%), of mean (±SD) age 55.6±15.5 years. Of these 214 subjects, 111 (52%) had a native AVF, while 103 (48%) had a PTFE graft. Both mean urea reduction ratio (native AVF=69±6.7% vs PTFE graft=70±7.3%; P=0.31), and mean serum albumin concentration (native AVF=4.02±0.39 g/dl vs PTFE graft=4±0.33 g/dl; P=0.59) were equivalent in both groups. Separate multiple logistic regression analyses with type of vascular access as one of the independent variables, found no significant relationship between type of vascular access and either a urea reduction ratio >65% (P=0.67), or a serum albumin concentration >4 g/dl (P=0.89), after adjustment for age of vascular access, access revision, location of access, dialyser urea clearance, length of dialysis treatment, body weight, and age. Conclusion: We conclude that PTFE grafts do not permit delivery of better dialysis than native AVF. The increasing use of PTFE grafts in the United States does not have any clinical justification.     

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.     

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.     

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.     

Use of arm and lesser saphenous vein compared with prosthetic grafts for infrapopliteal arterial bypass: Are they worth the effort?

Purpose: Arm and lesser saphenous veins (ALSVs) are generally considered to be the best alternative for infrapopliteal arterial bypass grafts when greater saphenous vein is not available. The need for additional incisions and repositioning of the patient, along with occasional use of general anesthesia for arm vein harvesting, led to our perception that the use of ALSVs increased operative time and possibly patient discomfort. Therefore, we compared the outcome of ALSVs with that of prosthetic infrapopliteal arterial bypass procedures performed at our hospital. Methods: Between July 1, 1991, and Dec. 31, 1996, we performed 96 infrapopliteal arterial bypass procedures using 45 ALSVs (28 arm vein, 17 lesser saphenous) and 51 polytetrafluoroethylene (PTFE) grafts. Seventy grafts were single-length ALSV or PTFE bypass grafts, and 26 grafts were placed as the distal segment of a sequential or composite bypass graft. Every attempt was made to use ALSV and avoid the use of PTFE, even if a short segment of the vein graft measured less than 4.0 mm in diameter. There were no significant differences between patients with ALSV compared with PTFE grafts in terms of age, sex, indication for surgery, or number of previous revascularization procedures (2.1 vs 1.7), respectively (p > 0.05). However, ALSV grafts had more factors associated with an expected worse outcome: they were more commonly anastomosed to pedal arteries (17% [8 of 45] vs 0%; p = 0.0009), less commonly single-segment grafts (62% [28 of 45] vs 82% [42 of 51]; p = 0.03), had higher average runoff resistance values (2.3 vs 1.5; p = 0.001), and were less frequently treated with lifelong warfarin (65% [29 of 45] vs 95% [48 of 51]; p = 0.0001). Results: The hospital mortality rate was 3.1% (3 of 96; 3 PTFE). All deaths were cardiac-related. Despite the potential factors associated with worse patency rates for ALSVs, 2-year assisted primary patency rates tended to be higher for arm veins (46%) than for lesser saphenous veins (23%) and PTFE grafts (26%), although this difference was not statistically significant. Limb salvage rates were similar between ALSV and PTFE grafts (76% vs 71%, respectively). The average operative time was significantly longer for ALSV bypass procedures (mean, 6.2 hours) than for PTFE bypass procedures (mean, 4.9 hours; p = 0.003), and for single-length conduits when revision of previously placed grafts was not attempted, the operative time was 4.0 hours for ALSV grafts and 2.5 hours for PTFE grafts. Conclusion: In our experience ALSV bypass grafts to infrapopliteal arteries do not function as well as reported by some others. In spite of the extra effort involved, arm vein grafts are preferred over PTFE grafts for their likely higher assisted primary patency rates and equivalent, if not better, limb salvage rates. (J Vasc Surg 1997;26:919-27.)     

Femoropopliteal bypass for claudication: Vein vs. PTFE

The vascular graft of choice for femoropopliteal bypass in patients with intolerable claudication is controversial. We retrospectively reviewed our experience with 239 patients suffering from claudication secondary to superficial femoral artery obstruction. Femoropopliteal reconstruction was performed with saphenous vein to the below-knee popliteal artery in 66 patients (BK-vein). Polytetrafluoroethylene (PTFE) was used in 128 patients as a bypass graft to the above-knee popliteal artery (AK-PTFE) and 45 patients had a PTFE graft to the below-knee popliteal artery (BK-PTFE). All patients were enrolled in a postoperative graft surveillance program with graft revision when appropriate. There was one perioperative death (0.4%). Primary patency at 5 years for AK-PTFE, BK-PTFE, and BK-vein was 58.0%, 55.0%, and 60.3%, respectively, and was not significantly different among the graft groups. Graft revision for failed/failing grafts resulted in 5-year secondary patency rates of 79.2% (AK-PTFE), 73.3% (BK-PTFE), and 74.4% (BK-vein). These secondary patency rates were not statistically different. Eventual conversion to a vein graft in patients initially treated with PTFE maximized patency in the femoropopliteal segment with 5-year patency rates of 84.6% and 93.0% for the AK-PTFE and BK-PTFE graft groups, respectively. Major leg amputation was necessary during the entire course of the study in eight (3.3%) patients. We conclude that long-term patency rates for femoropoliteal bypass in patients with intolerable claudication are similar for PTFE and autologous saphenous vein grafts.Presented at the Twentieth Annual Meeting of the Peripheral Vascular Surgery Society, New Orleans, La., June 10, 1995.     

Patency Rates of Cuffed and Noncuffed Extended Polytetrafluoroethylene Grafts in Dialysis Access: A Prospective,Randomized Study

Background  Although autogenous arteriovenous fistulae are the optimal route for dialysis access, extended polytetrafluoroethylene (ePTFE) grafts continue to be the preferred access for patients without suitable superficial veins. Among the common complications related to dialysis grafts, thrombosis due to graft outlet stenosis is the most frequently encountered clinical problem. A cuffed graft was designed to eliminate the outflow turbulence to reduce outlet stenosis and to enhance the clinical patency of ePTFE grafts. We conducted a prospective, randomized study to compare the clinical outcomes of cuffed ePTFE grafts and noncuffed grafts in dialysis access. Methods  Between November 2004 and October 2005, 89 ePTFE grafts were implanted for hemodialysis access in the upper extremities of end-stage renal patients. Graft selection was randomized, with patients receiving a cuffed graft (Venaflo) or a regular noncuffed graft (Stretch Gore-Tex). All patients were monitored for signs of thrombosis or other complications. Primary and secondary graft patency was analyzed by using a life-table analysis, and the log-rank test was applied to compare graft patencies. Results  Demographic data for both groups were similar without statistical difference. The primary patency rates and secondary patency rates at 12 months after implantation were 56% and 91% for cuffed grafts, and 41% and 78% for noncuffed grafts, respectively. The cuffed group outperforms the noncuffed group regarding primary and secondary patencies statistically. However, the incidence of other complications that required further surgery was similar in both groups. Conclusions  This investigation revealed that the cuffed ePTFE graft, which was designed to decrease graft outlet stenosis, may enhance the clinical patency rates of dialysis grafts.     

Impact of endothelial cell seeding on long-term patency and subendothelial proliferation in a small-caliber highly porous polytetrafluoroethylene graft

Previous reports have demonstrated that endothelial cell seeding of polytetrafluoroethylene (PTFE) grafts enhances short-term patency. This experiment was undertaken to study its impact on the long-term patency of a highly porous, experimental PTFE graft and to determine whether increasing the internodal distance of the graft material resulted in increased proliferation of the subendothelium. Ten centimeter long, 4 mm internal diameter segments of an unreinforced, experimental PTFE graft were implanted into 36 mongrel dogs as carotid interpositions. In each animal, one graft was seeded with autologous endothelial cells, enzymatically derived from the external jugular veins, whereas the contralateral graft was treated in identical fashion except that endothelial cells were not added to the preclot mixture. Nineteen animals were killed at 12 weeks; six at 22 weeks; eight at 26 weeks; and three at 52 weeks. The mean follow-up period was 20.1 weeks. The overall patency rate was 58.3% (21 of 36 grafts) for seeded grafts vs. 27.8% (10 of 36 grafts) for control grafts (p less than 0.01). The thrombus-free area was planimetrically measured at 83.4% +/- 4.5% in seeded grafts vs. 55.1% +/- 9.7% in control grafts (p less than 0.05). Scanning electron microscopy confirmed the presence of a confluent cellular monolayer in seeded grafts, whereas control grafts exhibited a variable coagulum of fibrin, platelets, and endothelial cells. The thickness of the subendothelial layer varied from 56 to 95 micron with no progressive increase in thickness between 12 and 52 weeks.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of Gore-Tex graft patency in hemodialysis access

Aim: The purpose of this retrospective study was to analyze the patency and complications of Gore-Tex grafts used in hemodialysis (HD) access. Methods: In the last 16 years, 1649 surgical procedures were performed on 655 patients to ensure and maintain permanent HD access. The study group consisted of 64 HD patients on whom 81 vascular synthetic PTFE Gore-tex grafts were performed. There were 28 males and 36 females, 3 of them were children (4.7%). Mean age was 54.2 years (range 15-77). Two types of Gore-Tex prosthesis were used: Diastat and Stretch. All grafts were implanted in the upper extremities. Kaplan-Meier survival curves were calculated to determine primary and secondary patency. Log-rank analysis was used to determine differences between curves. Results: Primary and secondary patency at 12 months was 52.5% and 67.5%, and at 18 months respectively 41.5% and 58.2%. The Diastat graft had a lower primary and secondary patency compared with the Stretch graft (respectively p = 0.02 and p = 0.008). Factors such as gender, coexisting diabetes and hypertension did not determine graft patency. Thrombosis was one of the most frequent complications. The remaining complications included stenosis, pseudoaneurysms, infection, steal syndrome and seroma. Conclusion: On the basis of our experience Stretch grafts appear a better option for creating vascular access for HD than Diastat grafts.