A comparison of femorocrural bypasses performed with modified heparin-bonded expanded polytetrafluorethylene grafts and those with great saphenous vein grafts to treat critical limb ischemia.

BACKGROUND: The purpose of this study was to evaluate our results involving femorocrural bypasses by comparing heparin-bonded expanded polytetrafluoroethylene (HePTFE) graft (Propaten) modified with handmade distal compliant HePTFE cuffs (mHePTFE graft) to great saphenous vein (GSV) graft. METHODS: A retrospective study involving 74 femorocrural bypasses performed from January 2010 to May 2013 at a single institution was carried out. The indication for revascularization was critical limb ischemia (Rutherford stages 4-6. Forty-one femorocrural bypasses were created in 37 patients with unavailable GSVs using modified ringed HePTFE grafts with a handmade distal radial stretch HePTFE cuff to reduce the mismatch compliance between the graft and the artery wall. Thirty-three femorocrural bypasses were created using a reversed GSV graft. The results were analyzed in terms of primary graft patency, limb salvage, and patient survival using univariate (Kaplan-Meier curves and log-rank test) and multivariate (Cox regression) analyses. RESULTS: The 2 groups were statistically comparable for main risk factors, Rutherford stage, and target artery for distal anastomoses. The run-off anatomy did not significantly differ between the prosthetic and the vein bypass group. The cumulative 30-day operative mortality rate was 2.9%. At 1, 2, and 3 years, the 2 groups were equivalent in primary graft patency (the mHePTFE group: 84%, 80%, and 70%, respectively; the GSV group: 84%,71%, and 71%, respectively; P = 0.93) and were also equivalent in terms of limb salvage (the mHePTFE group: 87%, 87%, and 76%, respectively; the GSV group: 84%, 75%, and 75%, respectively; P = 0.78) and patient survival (the mHePTFE group: 87%, 75%, and 75%, respectively; the GSV group: 87%, 73%, and 65%, respectively; P = 0.86). At Cox regression analysis, only postoperative treatment with warfarin therapy compared with double antiplatelet therapy was independently associated with poorer primary patency (P = 0.003; 95% confidence interval, 1.80-18.00; hazard ratio, 5.7). CONCLUSIONS: In this retrospective study regarding femorocrural bypasses, the mHePTFE grafts had 1-, 2-, and 3-year primary patency and limb salvage results which were not significantly different from those in the GSV grafts. Additional randomized data and larger studies are needed to confirm these results.

Prevention of neointimal hyperplasia associated with modified stretch expanded polytetrafluoroethylene hemodialysis grafts (Gore) in an experimental preclinical study in swine.

OBJECTIVE: Stenosis is the main cause of hemodialysis vascular graft failure and it is primarily caused by neointimal hyperplasia (NH) development at the vein-graft anastomosis. Even though NH development factors are well known, their activation pathway still remains disputed and the real role of the mismatch compliance between the vein and the graft wall has not yet been resolved. The purpose of this experimental study in swine was to verify the possibility of preventing the development of NH at the vein-graft anastomosis using a modified commercially available longitudinal stretch expanded polytetrafluoroethylene (ePTFE) Gore (W. L. Gore & Associates, Flagstaff, Ariz) graft (either standard or heparin-bonded) with an added handmade ePTFE radial stretch cuff at one end to reduce the compliance between the graft and the vein wall. METHODS: Twelve ePTFE stretch grafts (6 modified and 6 unmodified) were surgically placed as arterovenous grafts (AVGs) between the carotid artery and the external jugular vein in 6 pigs. In each pig, one modified graft was placed on one side and one corresponding unmodified graft on the other side as a control. In 4 pigs, standard stretch ePTFE Gore grafts were used, and in 2 pigs, heparin-bonded stretch Gore grafts were used; 2 pigs were also treated with antiplatelet drugs. All the implanted grafts had a total length of 8 cm and a diameter of 6 mm. The modified graft was realized by cutting a short segment of the commercially available graft lengthwise which was then sewn crosswise (rotated 90°) with the same diameter as the original graft and was then added to it. A Doppler ultrasound scan was used for monitoring the graft patency immediately, weekly, and before death. At death (21-28 days after implantation), artery, vein, and graft specimens were collected "en bloc" for histopathology. RESULTS: The modified grafts in the antiplatelet-treated animals were able to completely prevent NH development on vein wall (100% in 2 subjects) which was also reduced in antiplatelet untreated animals (66.5%, 96.4%, and 100% in 3 subjects, respectively). The modified standard stretch grafts and similarly modified heparin-bonded stretch grafts obtained the same good results in NH prevention. CONCLUSION: Data provide evidence of the efficacy of modified stretch ePTFE grafts with an added radial stretch cuff for the prevention of NH in swine models and support the hypothesis of the pivotal role of mismatch compliance between the graft and the vein wall in NH development.