Graft Description ( Identifier) Type of Tissue/Material Method Results Advantages Challenges
Cytograft Lifeline Graft (NCT00850252) Completely Biological-based, uses decellularized fibroblast scaffold seeded with fibroblasts and endothelial cells. Using cell sheet based techniques, autologous cells harvested and cultured.  Sheet of fibroblasts wrapped around mandrel and cultured, followed by decellularization.  Scaffolds wrapped in additional fibroblast sheet and lumen seeded with endothelial cells. Used as AV haemodialysis access, demonstrates primary patency of 78% at one month and 63% at 6 months.  Causes of graft failure include thrombosis, aneurysm, graft dilation [6]. Autologous and biologically based, allowing for the integration and dynamic remodeling of tissue.  Samples demonstrate mechanical properties similar to native vasculature.  Samples took 6 to 9 months for complete fabrication and maturation.  Use of autologous cells has high production costs, limited scale-up ability, and limited availability [88]. Cytograft is considering removing the endothelial layer, eliminating autologous fibroblasts to use allogenic cells. Also investigating alternative manufacturing process involving thread-based tissue engineering.
Angiotech Lifespan Graft (NCT00448708) Lifespan ePTFE graft Combined with Paclitaxel-eluting vascular mesh. Wrap placed around anastomosis to cover both heel and toe of graft, used for haemodialysis access. Clinical trial terminated due to number of graft infections.* ­Paclitaxel eluting mesh shown to inhibit neointimal hyperplasia in vivo. Clinical studies terminated prematurely due to number of graft infections. Previous separate clinical trials as peripheral bypass graft showed no significant differences compared to pure ePTFE grafts (109 subjects) [201].
NonWoTecc Medical Gmbh ProEndoTecc Vascular Graft (NCT01095237) Proprietary form of polycarbonate urethane (PCU). PCU exterior with biomimetic ECM allowing for the recruitment of intraluminal endothelium progenitor cells (EPC) as well as connective tissue. Trials in-progress. Estimated completion date: December 2012. Used as femoral artery bypass/interponate grafts.* Luminal surface allows for EPC seeding thereby reducing thrombogenesis. Extraluminal connective tissue integration mimics natural mechanical and elastic properties. Polyurethanes have shown variable clinical results in vascular solutions due to thrombogenecity and aneurysm formation [61, 64,67], often attributed to degradation mechanisms and byproducts.
Gore Propaten Vascular Graft (NCT00205790) CARMEDA Bioactive Surface (CBAS)-bound heparin ePTFE luminal surface. ePTFE graft with a heparin-treated luminal surface. Used in below-knee bypasses (femoral-popliteal & infrapopliteal). N=494. 82% patency after 12 mos. 75% patency after 24 mos., 68% patency after 36 mos. Coating reduces the risk of occlusion by 50% for patients with critical limb ischemia. Utilizes thromboresistant properties of heparin on luminal surfaces to achieve long-term patency similar to autologous vascular grafts. ePTFE graft is non-degradable and does not allow for complete tissue integration.
Gore Acuseal Vascular Graft (NCT01173718) Tri-layered graft with ePTFE outer layer, elastomeric middle and heparin-bonded ePFTE inner layer. Similar to Propaten graft with same heparin-bonded luminal surface with inclusion of elastomeric middle membrane imparting increased flexibility and resilience. CBAS-surface prevents occlusion when compared to totally occluded non-CBAS surface at 60 minutes. Explanted grafts remained clot free at 3 years. 20% improvement (n= 83 vs n=67) in clot-free survival compared to standard ePTFE grafts at 12 mos.** Elastomer yields flexibility for kink-resistance as well as minimizes cannulation-associated bleeding. Proprietary CBAS heparin binding provides thromboresistance.  ePTFE graft is non-degradable and does not allow for complete tissue integration.
Hemosphere, Inc. HeRO (Hemodialysis Reliable Outflow) Graft (NCT00890045) Two-component graft: nitinol (memory metal) venous outflow & ePTFE arterial graft components. Venous component inserted directly into right atrium and then connected to arterial graft, which is then anastomosed to target artery. Reduced infection rates by 69% compared to standard dialysis catheters. Improved dialysis adequacy (Kt/V = 1.7). Demonstrated patency similar to conventional grafts. Primary patency rates around 40%. ** Only FDA approved long-term AV access solution for patients with central vein stenosis. Significant cost savings associated with infection reduction as well as associated catheter-intervention costs and heparin therapies. Currently only used after central vein stenosis. Patients not candidates prior to stenosis. Possible allergic reactions to nickel-containing nitinol.  Initial reports require intervention to treat thrombosis, but maintain secondary patency [202, 203].
LeMaitre Vascular Expedial Vascular Access Graft (NCT00131872) Heparin-impregnated polycarbonate urethane (PCU) with kink-resistant diagonal outer mesh. N/A Clinical Trial terminated during Phase II due to unfavorable preliminary data.* Self-sealing device post-suturing minimizing blood loss and time to hemostasis. Heparin inclusion provides early-on thromboresistance. Not currently approved in U.S. International clinical trials have demonstrated acceptable patency, low complication rates, and short maturation times as an alternative AV access [204].
Artegraft Bovine Carotid Artery graft (NCT 01021839) Bovine xenograft composed of crosslinked collagen. Bovine Carotid Artery chemically processed to become an acellular, nonantigenic collagen graft. Collagen then crosslinked by a Dialdehyde starch process for added durability. 26 patients BCA 27 patients ePTFE. Primary & assisted primary patency rates higher in BCA than ePFTE at 1 year (60.5% vs 10.1% and 60.5% vs 20.8% respectively). Secondary patency similar, 64.1% for BCA and 59.2% for ePFTE at 2 years. Number of interventions & angioplasties significantly fewer in BCA group [205]. BCA graft has less inflammatory response at implantation site and less infectious complications. It also lends itself to easier surgical handling. Graft thrombosis most common complication. Long term durability of the BCA graft also an issue.
Breuer & Shin’oka TEVG – Yale University School of Medicine  (NCT01034007) L-lacide & ε-caprolactone (50:50) copolymer scaffold seeded with autologous bone marrow cells supported by polyglycolic acid woven fabric. Mononuclear cell component of autologous bone marrow was seeded onto biodegradable scaffold of polyglycolic acid and ε-caprolactone/L-lactide and implanted as extracardiac cavopulmonary conduits. Results from 25 grafts implanted as extracardiac cavopulmonary conduits demonstrated no evidence of aneurysm formation, graft rupture, calcification or any other graft-related mortality (Median follow-up time 5.8 yrs) [5]. Autologous cell seeding increases biocompatibility as well as decreases risk of immunogenicity.  Potential for wide variety of vascular applications. Studies show promising results in children, a challenging field in vascular engineering. Polymer interactions in body are not yet fully understood. Autologous cell harvesting increases risk of adverse side effects as well as increases time to availability. Currently only used for larger diameter vasculature (>12mm).
Maquet Vascular Grafts : EXXCEL and FUSION Bioline (NCT01113892) FUSION: ePFTE merged with PET. EXXCEL: ePTFE. FUSION: 2 layer construction: Inner layer of extruded ePFTE, outer layer knit polyester textile. Bioline coating composed of recombinant human albumin and heparin EXXCEL: Removable support coil for customization. PTFE graft wrapped with a cross-helical, nonporous PTFE yarn to increase radial strength properties, covering ~70% of the external graft surface. Trials in-progress. Estimated completion date: September 2013.* FUSION: High suture retention strength, better handling than standard ePFTE grafts, minimal suture hole bleeding, anthrombogenic coating. EXCELL: designed to improve lumen integrity for peripheral vascular bypass procedures and vascular access procedures for dialysis access management. Consistent strength throughout graft. Designed for good performance along line of anastomosis. EXXCEL does not have longitudinal elasticity.
ASC Coated ePTFE Vascular Graft (NCT01305863) ePFTE and adipose-derived stromal cells (ASC). ePFTE graft with ASC—  a stem-cell based biological coating, seeded onto lumen. The ASC is isolated from autologous adipose tissue by the company’s Cell Isolation System. Study uses coated BARD IMPRA ePTFE graft vs. Gore PROPATEN (heparin-coated ePTFE) graft, used for peripheral bypass graft. Trials in-progress. Estimated completion date: September 2013.* Closely mimics native veins. Expected to last longer functionally, as well as being more cost effective. Requires harvesting of autologous stem cells.
*Results/information from
**Results/information from Company Website
Table 1: Current / Recent Clinical Trials in the United States – Small Diameter Vascular Applications.