Matching Static and Dynamic Compliance of Small-Diameter Arteries, with Poly (lactide-co-caprolactone)Copolymers: In Vitro and In Vivo Studies.

Mechanical mismatch between vascular grafts and blood vessels is a major cause of smaller diameter vascular graft failure. To minimize this mismatch, several poly-l-lactide-co-e-caprolactone (PLC)copolymers are evaluated as candidate materials to fabricate a small diameter graft. Using these materials, tubular prostheses of 4 mm inner diameter are fabricated by dip-coating. In vitro static and dynamic compliance tests are conducted, using custom-built apparatus featuring a closed flow system with water at 37 °C. Grafts of PLC monomer ratio of 50:50 are the most compliant (1.56percent ± 0.31·mm Hg-2), close to that of porcine aortic branch arteries (1.56 percent ± 0.43·mm Hg-2), but underwent high continuous dilatation (87 µm min-1). Better matching is achieved by optimizing the thickness of a tubular conduit made from 70:30 PLC grafts. In vivo implantation and function of a PLC 70:30 conduit of 150 µm wall-thickness (WT)are tested as a rabbit aorta bypass. An implanted 150 µm WT PLC 70:30 prosthesis is observed over 3 h. The recorded angiogram shows continuous blood flow, no aneurysmal dilatation, leaks, or acute thrombosis during the in vivo test, indicating the potential for clinical applications