Stent types and uses
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Types of Stents: Cardiovascular, Ureteral, Airway, and More
Stents are small, tube-like medical devices used to keep various body passages open, most commonly blood vessels, but also the ureter, airways, and other conduits. The main types of stents include vascular (such as coronary artery stents), ureteral stents, airway stents, and specialized stents for other body conduits like the esophagus and trachea 1259.
Cardiovascular Stents: Bare Metal, Drug-Eluting, and Bioresorbable
Cardiovascular stents are primarily used to treat narrowed or blocked arteries, especially in coronary artery disease. The main types are:
- Bare Metal Stents (BMS): The earliest stents, made of metal, provide structural support to keep arteries open but are prone to restenosis (re-narrowing) 1378.
- Drug-Eluting Stents (DES): These stents are coated with drugs that help prevent tissue growth that can block the artery again, significantly reducing restenosis compared to BMS 13478.
- Bioresorbable Stents (BRS): Designed to dissolve over time, these stents provide temporary support and drug delivery, then gradually transfer the load to the vessel wall, eliminating the need for removal and reducing long-term complications 1457.
Ureteral Stents: Materials and Innovations
Ureteral stents are used to maintain urine flow from the kidney to the bladder, often after surgery or to relieve obstruction. The most common type is the double J stent, made from materials like polyurethane or silicone. Metal stents are used for long-term cases due to their resistance to compression, while biodegradable stents are being developed to avoid the need for removal, though their safety is still under evaluation. Coated and drug-eluting ureteral stents are experimental but show promise in reducing stent-related symptoms 25.
Airway Stents: Silicone and Metallic Options
Airway stents are used to keep the trachea or bronchi open, mainly in cases of malignant or benign obstruction. Both silicone and metallic stents are available, each with specific advantages and limitations. Stents are typically used when surgery is not an option, and their design and removal can be complex 59.
Stent Design and Performance: Self-Expanding vs. Balloon-Expandable
Stents can be categorized by their expansion mechanism:
- Self-Expanding Stents: Made from materials like nitinol, these stents expand on their own once deployed, providing flexible, anatomically conforming support, especially useful in vessels that move or bend .
- Balloon-Expandable Stents: These require a balloon to be inflated during placement, offering rigid support and precise placement, often used in coronary arteries .
Materials and Coatings: Enhancing Stent Functionality
Stents are made from metals (such as stainless steel, cobalt-chromium, or nitinol) or polymers. Coatings can include drugs, polymers, biological agents, or inorganic materials to improve biocompatibility, control degradation, and reduce complications like restenosis and thrombosis 37.
Uses and Applications Across the Body
While most commonly associated with cardiovascular disease, stents are also used in:
- Ureteral obstructions (kidney stones, tumors)
- Airway obstructions (tumors, strictures)
- Other conduits such as the esophagus and bile ducts
Future Trends and Innovations in Stent Technology
The stent market is growing, with ongoing research focused on improving materials, coatings, and designs to enhance safety, reduce complications, and expand applications. Bioresorbable and drug-eluting stents are key areas of innovation, aiming to provide temporary support and targeted therapy without long-term foreign material in the body 1457.
Conclusion
Stents are vital medical devices used to maintain the patency of various body conduits, with types and materials tailored to specific uses such as cardiovascular, ureteral, and airway applications. Advances in stent technology, including drug-eluting and bioresorbable designs, continue to improve patient outcomes and expand the range of treatable conditions 12345678+1 MORE.
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