Lack of long-term patency has hindered the clinical use of small-diameter prosthetic vascular grafts with the majority of these failures due to the development of neointimal hyperplasia. Previous studies by our laboratory revealed that small-diameter expanded polytetrafluoroethylene (ePTFE) grafts coated with antioxidant elastomers are a promising localized therapy to inhibit neointimal hyperplasia. This work is focused on the development of poly(diol-co-citrate-co-ascorbate) (POCA) elastomers with tunable properties for coating ePTFE vascular grafts. A bioactive POCA elastomer (@20 : 20 : 8, [citrate] : [diol] : [ascorbate]) coating was applied on a 1.5 mm diameter ePTFE vascular graft as the most promising therapeutic candidate for reducing neointimal hyperplasia. Surface ascorbate density on the POCA elastomer was increased to 67.5 ± 7.3 ng mg⁻¹ cm⁻². The mechanical, antioxidant, biodegradable, and biocompatible properties of POCA demonstrated desirable performance for in vivo use, inhibiting human aortic smooth muscle cell proliferation, while supporting human aortic endothelial cells. POCA elastomer coating number was adjusted by a modified spin-coating method to prepare small-diameter ePTFE vascular grafts similar to natural vessels. A significant reduction in neointimal hyperplasia was observed after implanting POCA-coated ePTFE vascular grafts in a guinea pig aortic interposition bypass graft model. POCA elastomer thus offers a new avenue that shows promise for use in vascular engineering to improve long-term patency rates by coating small-diameter ePTFE vascular grafts.

Cardiovascular disease (CVD) is the number one cause of death globally. CVD treatments range from dietary to pharmaceutical to surgical interventions. Vascular grafts are used to replace or bypass a damaged or occluded vessel, and prosthetic grafts are used when autologous vein is not available. However, a major limitation, especially of small-diameter prosthetic grafts, is reduced

Severe peripheral arterial disease (PAD) is often treated with surgical bypass grafting using autologous vein. When veins are unavailable, small-diameter expanded polytetrafluoroethylene (ePTFE) grafts are used but are associated with long-term poor performance. To address this, we developed poly(1,8-octanediol-co-citrate-co-ascorbate) (POCA) elastomer coatings for small-diameter ePTFE grafts that indirectly release nitric oxide via decomposition of circulating S-nitrosothiols (RSNO). Graft in vivo efficacy was assessed using a guinea pig aortic interposition model to evaluate neointimal formation. After 4 weeks, POCA-Grafts demonstrated significantly less occlusion compared to uncoated ePTFE grafts (16.8 % versus 29.7 %, p < 0.0005) and POC (poly(1,8-octanediol-co-citrate))-Grafts without ascorbate (16.8 % versus 19.9 %, p < 0.005). POCA-Grafts showed a 1.6-fold increase in endothelial cell coverage and significantly reduced leukocyte and macrophage infiltration compared to uncoated ePTFE grafts, particularly in female animals. These results suggest that the POCA coating enhances graft biocompatibility by promoting endothelialization and reducing inflammation, thereby inhibiting neointimal hyperplasia and improving graft patency. Overall, these results highlight the therapeutic potential of an ascorbate-functionalized poly(diol-co-citrate) elastomer for vascular applications and support future evaluation in large animal models.