selfexpandingstentit

Self-expanding stents are intravascular implants designed to keep arteries open by exerting outward radial force after deployment. They are typically made from nitinol, a shape-memory or superelastic alloy, and are delivered in a constrained state through a catheter. Upon release, they autonomously expand to their preset diameter, conforming to the vessel wall.

Design and behavior rely on the material properties rather than balloon inflation to achieve expansion. They are often braided or laser-cut from a tube and may conform better to tortuous anatomy and irregular vessel contours than balloon-expandable devices. They can provide gradual expansion and adaptive fit to vessel shape, but some designs may exhibit foreshortening during deployment or incomplete apposition in certain lesions.

Clinical use includes treatment of atherosclerotic stenosis in peripheral arteries such as the superficial femoral and iliac arteries, as well as intracranial vessels where navigation and flexibility are advantageous. They are commonly employed in carotid and neurovascular procedures where gentle radial force and conformity to vessels are beneficial. Post-implantation antithrombotic therapy is typically required, with decisions guided by the vessel treated and the device used.

Considerations and limitations include potential differences in radial strength compared with balloon-expandable stents and risks such as stent recoil, malapposition, or restenosis depending on design and lesion characteristics. Long-term patency depends on patient factors and lesion biology, making selection of device type and strategy case-specific.

History notes that self-expanding stents gained prominence in the 1990s with nitinol technology, offering enhanced conformability in tortuous vessels. They have since become widely used in both peripheral and neurovascular interventions alongside balloon-expandable stents.