Sustained Thromboresistant Bioactivity with Reduced Intimal Hyperplasia of Heparin-Bonded Polytetrafluoroethylene Propaten Graft in a Chronic Canine Femoral Artery Bypass Model.

BACKGROUND: Bypass graft thrombosis remains a significant mode of failure in prosthetic graft revascularization. The purpose of this investigation was to evaluate the long-term thromboresistant effect of heparin-bonded expanded polytetrafluoroethylene (ePTFE) graft using Carmeda BioActive Surface technology in a canine model. METHODS: Bilateral femorofemoral artery bypass grafts with ePTFE grafts were performed in 25 adult grayhound dogs. In each animal, a heparin-bonded ePTFE graft (Propaten, WL Gore) was placed on one side, whereas a control nonheparin graft was placed on the contralateral side. The graft patency was assessed at 1, 6, 12, 18, and 24 months (n = 5 per group) following the bypass. Heparin bioactivity of the graft material was analyzed. The effect of intimal hyperplasia was also assessed. RESULTS: All bypass grafts were patent at 1 month. Significantly greater patency rates were noted in the Propaten group compared to the control group at 12, 18, and 24 months, which were 84%, 80%, and 80% vs. 55%, 35%, and 20%, respectively (P < 0.02). There was a significant reduction in the anastomotic neointimal area and neointimal cell proliferation in Propaten grafts compared with control grafts at all groups between 6 and 24 months (P < 0.05). Heparin bioactivity as measured by antithrombin binding assay was demonstrated in the Propaten graft between 1 and 24 months. Mean heparin activities on Propaten grafts ranged from 26.3 ± 6.4 pmol/cm2 to 18.4 ± 8.7 pmol/cm2 between 1 and 24 months, which were significantly greater than the control group (P < 0.001). Differences between mean heparin activities of explanted Propaten graft samples at the various time points were nonsignificant (P > 0.05). CONCLUSIONS: Heparin-bonded ePTFE graft provides a thromboresistant surface and reduced anastomotic intimal hyperplasia at 2 years. The stable heparin bioactivity of the Propaten graft confers an advantage in long-term graft patency.

Comparison of ASPIRE Mechanical Thrombectomy Versus AngioJet Thrombectomy System in a Porcine Iliac Vein Thrombosis Model.

BACKGROUND: Percutaneous mechanical thrombectomy device has become an important therapeutic armamentarium in the management of venous thromboembolism. In this study, we compare the efficacy and safety profile of the AngioJet thrombectomy device and ASPIRE thrombectomy system in a porcine venous thrombosis model. METHODS: Twelve adult pigs underwent bilateral iliac venous thrombosis created by using a stent graft thrombosis model and subsequently underwent either AngioJet (n = 6) or ASPIRE mechanical thrombectomy (n = 6) 1 week later. Intravascular ultrasound (IVUS) was used to assess thrombectomy efficacy, and computed tomography was used to evaluate pulmonary embolism (PE). Hemolytic effect was measured by plasma-free hemoglobin (PfHgb). Iliac vein thrombogenicity was evaluated with radiolabeled platelet and fibrin deposition. Veins were harvested and evaluated with light microscopy and scanning electron microscopy (SEM). RESULTS: Similar thrombectomy efficacy by IVUS evaluation was noted in both groups. Significant greater PE and hemolysis were identified in the AngioJet group compared to the ASPIRE group. The AngioJet group had greater reduction in WBC and platelet compared to the ASPIRE group. No difference was found in thrombogenicity, light microscopic evaluation, or SEM. CONCLUSIONS: Both devices had similar thrombectomy efficacy and thrombogenicity response. The ASPIRE catheter incurred less PE and hemolysis compared to the AngioJet device. Vessel wall response by histological analysis and SEM was similar in both groups.