Three-Dimensionally Printed Self-Expanding Polylactic Acid Stent for Assisting Arteriovenous Fistula Maturation

This study presents the development of a novel biodegradable, self-expanding stent designed to facilitate arteriovenous fistula (AVF) maturation. The stent, made of polylactic acid (PLA), is engineered to be crimped into a standard 6 Fr (2 mm) catheter for delivery and to self-expand, increasing the vein diameter beyond 4.2 mm with the aid of pre-strained elastic lines, thereby enhancing maturation rates. A validated finite element model was utilized to design the stent, ensuring it meets functional requirements with less than 3% strain in both crimped and fully expanded states. The stent prototype was fabricated using a modified fused deposition modeling (FDM) 3D printer, and the Taguchi method was employed to optimize manufacturing parameters, achieving strut width and thickness variations of less than 5%. Experimental validation demonstrated that the PLA stent could be crimped to 2 mm, self-expand to 6.4 mm, and deliver a radial force of 0.08 N/mm, meeting the performance requirements of AVF stents. Additionally, the stent exhibits excellent elasticity post-implantation, minimizing the risk of damage from external forces, and fully degrades after AVF maturation, reducing the risk of long-term vascular obstruction and related complications. This novel stent design offers a promising biodegradable solution for enhancing AVF maturation and improving patient outcomes.