3D Printing Method Could Enable More Flexible Cardiovascular Implants

Rigid structures can become too stiff during compression, potentially increasing the risk of vascular injury. To support more flexible designs, researchers have developed a three-dimensional printing method for nitinol devices that could expand options for personalized cardiovascular implants.

An international team led by IMDEA Materials Institute and Universidad Politécnica de Madrid developed the method in collaboration with the Massachusetts Institute of Technology and the University of Galway. The approach uses three-dimensional printing of nitinol, a superelastic nickel-titanium alloy, to manufacture braided cardiovascular structures in a single production step. The technology has been patented and recognized with the National James Dyson Award.

The printed structures are designed to mimic blood vessels while providing the flexibility needed for catheter-based delivery. Their interwoven filaments move and reorient during deformation, whereas conventional lattice structures rely on bending rigid struts. To prepare the printed surfaces for potential implantation, the team applied chemical etching and electropolishing to achieve a biomedical-grade finish. This post-processing reduced fiber thickness by 47.7% and cross-sectional area by 71.1% compared with the as-printed structures.

Mechanical testing demonstrated how this braided architecture performed under compression. The stents withstood compression of up to 50% of their original diameter while maintaining more than 90% elastic recovery, and their chronic outward force was up to five times lower than that of conventional lattice structures.

By comparison, the researchers reported that conventional lattices became excessively stiff during compression and faced fracture risk at strains approaching 25%. Prototype validation used widely accepted mechanical performance indicators and a single compression-expansion cycle designed to replicate catheter insertion and deployment.

The findings were published in npj Metamaterials on September 30, 2026.. Further work will include in vitro biocompatibility testing and animal studies before clinical investigations in patients can begin. The researchers also identified neurovascular devices for difficult-to-access brain vessels as a future direction. This work will require further miniaturization of complex nitinol structures and exploration of ultra-high-precision three-dimensional printing and magnetic functionalization.

“The clinical impact of nitinol-based MITDs has been transformative for cardiovascular interventions. However, despite their widespread clinical adoption, current manufacturing methods impose fundamental geometric limitations that restrict their optimization and personalization. While recent advances in powder metallurgy-based techniques, such as spark plasma sintering, have expanded the manufacturing possibilities for these devices, it remains challenging to develop implants that combine complex geometries, mechanical flexibility and patient-specific anatomical adaptation,” said Dr. Carlos Aguilar Vega, one of the authors of the publication.

Related Links
MDEA Materials Institute
Universidad Politécnica de Madrid