Use Of ePTFE Graft Research Articles

Anterior sector outflow reconstruction using polytetrafluoroethylene (PTFE) graft in right lobe living donor liver transplantation

Presenter: Ashish Singhal MBBS, DNB | Fortis Hospitals Background: Outflow reconstruction is very important especially in right lobe (RL) LDLT without MHV. Preserving the MHV with donors add to donor safety but leads to multiple segmental veins in the graft. We aim to describe our surgical technique of anterior sector venous reconstruction using expanded polytetrafluroethylene (ePTFE) graft. Methods: Retrospective analysis of 760 primary RL-LDLTs between December 2011 and June 2018. On bench, we created a “Neo-MHV” using ePTFE graft and anastomosing to segment 5/8 veins in an end-to-end/end-to-side fashion. In past, graft RHV and Neo-MHV were anastomosed to IVC at separate sites. Since February 2016, the end of Neo-MHV was anastomosed with end of graft RHV in side-to-side fashion to create a common ostium and this was anastomosed to caval RHV orifice (single composite drainage). Reconstruction of AS: ePTFE (group A, n = 705) and autologous vein (group B, n = 55). Results: Pre-transplant characteristics were comparable among both groups. Group A has significantly lower CIT (68.7 ±.3.5 minutes vs. 127.8 ± 7.2 minutes; p <.001) and anhepatic time (116.3 ± 5.5 mins vs. 190.81 ± 9.35 mins; p < 0.001). There was no difference in recovery pattern of liver functions, morbidity, and mortality between the two groups. One and 6-months patency rates of interposition grafts were 97.6% and 84.4% (group A) and 96.4% and 78.1% (group B) respectively. Conclusion: In centers with limited access to homologous or autologous vascular grafts, use of ePTFE graft for AS venous outflow reconstruction in RL-LDLT is a viable option with excellent patency and patient outcomes.

Improved Patency of ePTFE Grafts as a Hemodialysis Access Site by Seeding Autologous Endothelial Cells Expressing Fibulin-5 and VEGF.

Small caliber synthetic vascular grafts used for dialysis access sites have high failure rates due to neointima formation andthrombosis. Seeding synthetic grafts with endothelial cells (ECs) provides a biocompatible surface that may prevent graft failure. We tested the use of ePTFE grafts seeded with autologous ECs expressing fibulin-5 and vascular endothelial growth factor (VEGF), as a dialysis access site in a porcine model. We connected the carotid arteries and jugular veins of 12miniature pigs using 7-mm ePTFE grafts; five grafts were seeded with autologous venous ECs modified to express fibulin-5 and VEGF, and seven unseeded grafts were implanted at the same location and served as controls. At 6months, after completion of angiography, the carotid arteries and jugular veins with the connecting grafts were excised and fixed. Autologous EC isolation and transduction and graft seeding were successful in all animals. At 3months, 4 of 5 seeded grafts and 3 of 7 control grafts were patent. At 6months, 4 of 5 (80%) seeded grafts and only 2 of 7 (29%) control grafts were patent. Seeding ePTFE vascular grafts with genetically modified ECs improved long term small caliber graft patency. The biosynthetic grafts offera novel therapeutic modality for vascular access in hemodialysis.

Management of Extensive Retrohepatic Vena Cava Defect in Recipients of Living Donor Liver Transplantation

Certain complexities, such as extensive vena caval injury, unexpected dense adhesions between liver and retrohepatic vena cava, and liver tumor abutting retrohepatic vena cava, sometimes warrant resection of vena cava during living-donor liver transplantation. Because the donor graft is devoid of vena cava, reconstruction of the retrohepatic cava is required, which can be done with the use of either a cryopreserved venous graft or an artificial conduit. With only a few published reports, the experience in vena cava reconstruction with the use of expanded polytetrafluoroethylene (ePTFE) during living-donor liver transplantation remains limited. We present our experience of 4 patients who successfully underwent vena caval resection during liver transplantation for various indications, which was subsequently reconstructed with the use of ePTFE grafts. All of these patients except 1 recovered well without any undue complications, such as thrombosis or outflow inadequacies, thus proving this extensive surgical treatment to be a successful and life-saving procedure, though meticulous skills are prerequisite.

Dacron or ePTFE graft for above-knee femoropopliteal bypass reconstruction. A bi-centre randomised study

The objective of this study was to compare polyester (Dacron) and expanded polytetrafluorethilene (ePTFE) grafts for above-knee femoropopliteal bypass. Eighty five patients with disabling claudications or limb threatening ischemia suitable for above-knee femoropopliteal reconstruction were randomized into two groups. In the first group the surgery was performed using 8 mm Dacron graft, whereas the patients in the second group were operated using ePTFE grafts. The primary patency rates for Dacron and ePTFE were 100 %, and 88.37 % (p < 0.05), while secondary patency rates were 83.3 % and 75 % (p > 0.05) respectively. The early limb salvage rates for Dacron and ePTFE were 100 % and 97.7 % (p > 0.05). Early (30-day) complications (bleeding 2.38 % and 2.32 %; wound infection 11.9 % and 11.63 %) occurred in both groups with similar frequency (p > 0.05). The patients were followed up over a period of 6 to 12 months (mean 8.3 +/- 3.6 months). The overall mortality rate in the follow-up period was 2.38 % (one patient) for Dacron and 6.98 % (three patients) for ePTFE group (p > 0.05). Late graft infection was noted in three patients (7.1 %) in Dacron, and two patients (4.65 %) in ePTFE group (p > 0.05). Primary patency rates were not significantly influenced by obesity, diabetes, hypertension, hyperlipidemia, cigarette smoking, (p > 0.05). However, poor run-off (only one crural artery patent on preoperative angiography) significantly decreased patency of both grafts and favored the use of ePTFE graft (p < 0.05). This study confirms that both materials are suitable for above-knee femoropopliteal reconstructions. Above-knee femoropopliteal bypass does not have a good long-term prognosis in the presence of poor run-off.

Is the Preferential Use of ePTFE Grafts in Femorofemoral Bypass Justified?

The choice of prosthetic graft material for cross-femoral bypass has been evolving in the past two decades. Expanded polytetrafluoroethylene (ePTFE) has become our preferred graft material since 1995. However, few studies have looked into the optimal graft material in this procedure. Justification for the preferential use of ePTFE graft in lower limb revascularization remains unknown. The aim of the present study was to compare the long-term outcomes of Dacron and ePTFE grafts in femorofemoral bypass. The records of 61 consecutive patients who underwent femorofemoral bypass at the University of Hong Kong Medical Center from 1981 to 1998 were retrospectively reviewed. Dacron grafts were used in 27 patients and 34 patients had ePTFE grafts. The demographic features, patency, and limb salvage rates of the two groups of patients were compared. The 3-year primary patency rates of Dacron and ePTFE grafts were 85% (SE = 9.5%) and 66% (SE = 14.5%), respectively. The difference was not statistically significant. The limb salvage rates of Dacron and ePTFE grafts were 91% and 83% at 3 years, respectively (p = 0.27). The long-term outcomes of Dacron and ePTFE grafts in femorofemoral bypass were equivalent. The preferential use of ePTFE graft in femorofemoral bypass is not evidence based. Selection of an appropriate prosthetic graft for femorofemoral bypass should be based on the cost and its handling characteristics.

Femoral-infrapopliteal bypass with prosthetic grafts

Patients who require prosthetic infrapopliteal of the lower extremity have historically had dismal long-term results. This study examined the outcome of patients undergoing femoral-distal arterial bypass with expanded polytetrafluoroethylene (ePTFE) grafts. Femoral to infrapopliteal artery bypasses with ePTFE performed between 1990 and 1997 were reviewed. Graft patency, limb salvage, and survival rates were calculated by actuarial analysis. Different anastomotic adjuncts (direct end-to-side anastomosis, vein patch anastomosis, and arteriovenous fistula [AVF] anastomosis) were compared with the log-rank test. Seventy-four femoral-infrapopliteal bypasses with ePTFE were performed in 67 patients for limb salvage. At 24 months the primary patency, assisted primary patency, and secondary patency rates were 40% +/- 10% (SEMAI), 48% +/- 11%, and 52% +/- 11%, respectively. Limb salvage was successful in 62 % +/- 10% of the bypasses at 24 months. Forty-six percent of the bypasses were performed with an AVF; 35% were performed with direct end-to-side anastomosis, and 19% were performed with a vein patch anastomosis. Apparent trends in favor of the AVF group did not attain statistical significance with 24-month patency rates of 65% +/- 19%, 44% +/- 16%, and 35% +/- 20%, respectively, in the 3 subgroups. Limb salvage rates were similar (64% +/- 17%, 56% +/- 15%, and 76% +/- 22%, respectively) at 24 months. Patency and limb salvage rates are sufficient to justify the use of ePTFE grafts in infrapopliteal bypass when adequate autogenous material is unavailable.

Femoral-infrapopliteal bypass with prosthetic grafts

<h2>Abstract</h2> <b>Background:</b> Patients who require prosthetic infrapopliteal of the lower extremity have historically had dismal long-term results. This study examined the outcome of patients undergoing femoral-distal arterial bypass with expanded polytetrafluoroethylene (ePTFE) grafts. <b>Methods:</b> Femoral to infrapopliteal artery bypasses with ePTFE performed between 1990 and 1997 were reviewed. Graft patency, limb salvage, and survival rates were calculated by actuarial analysis. Different anastomotic adjuncts (direct end-to-side anastomosis, vein patch anastomosis, and arteriovenous fistula [AVF] anastomosis) were compared with the log-rank test. <b>Results:</b> Seventy-four femoral-infrapopliteal bypasses with ePTFE were performed in 67 patients for limb salvage. At 24 months the primary patency, assisted primary patency, and secondary patency rates were 40% ± 10% (SEM), 48% ± 11%, and 52% ± 11%, respectively. Limb salvage was successful in 62% ± 10% of the bypasses at 24 months. Forty-six percent of the bypasses were performed with an AVF; 35% were performed with direct end-to-side anastomosis, and 19% were performed with a vein patch anastomosis. Apparent trends in favor of the AVF group did not attain statistical significance with 24-month patency rates of 65% ± 19%, 44% ± 16%, and 35% ± 20%, respectively, in the 3 subgroups. Limb salvage rates were similar (64% ± 17%, 56% ± 15%, and 76% ± 22%, respectively) at 24 months. <b>Conclusions:</b> Patency and limb salvage rates are sufficient to justify the use of ePTFE grafts in infrapopliteal bypass when adequate autogenous material is unavailable. (Surgery 1999;126:759-65.)