Silicone-based vascular prosthesis: assessment of the mechanical properties

We introduce a silicone-based vascular prosthesis that may be optimized in various ways. The current work describes the theoretical background, the fabrication process, and the mechanical properties of these new prostheses, allowing objectification and comparison of materials used in vascular surgery. A production process to coat polyester prostheses with silicone-rubber (polydimethylsiloxane, PDMS) was established. Further modifications (surface improvements, drug incorporation for release) can be performed wet-chemically. Measurement of the physical properties included longitudinal and circumferential stability and elasticity, suture retention strength and puncture resistance (tensile testing machine), permeability, and compliance (circulation model). Prostheses can be multiply coated with PDMS. Sufficiently low levels of permeability (<5 mL/cm(2)/min at 120 mm Hg) were achieved with a PDMS content >15 mg/cm(2). Considering stability, elasticity, and compliance, prostheses with a silicone-rubber content of 15-20 mg/cm(2) are comparable to conventional, primarily tight prostheses. Coating with PDMS decreases suture retention strength and puncture resistance compared to conventional alloplastic materials (collagen-coated polyester and expanded polytetrafluorethylene) materials. The silicone coating surrounds the passing threads ("self-sealing surface") and is resistant to clamping trauma. The complete measurement procedures described here allow for a comparison of new materials with conventional ones and allow the handling characteristics of implants to be objectified. The primarily tight, silicone-coated prostheses can be compared to conventional bovine-coated materials without drawbacks regarding physical properties.