Coronary Stent Materials

Introduction to Stent Materials

The American Heart Association notes that coronary stents are primarily made of metal alloys, with bare-metal stents composed of stainless steel or cobalt-chromium alloys, while drug-eluting stents use these same metal scaffolds coated with antiproliferative drugs delivered via polymer systems 1

The American College of Cardiology recommends the use of stainless steel (316L) as the original and most widely used material for first-generation coronary stents, due to its strength, ductility, corrosion resistance, and acceptable biocompatibility 1
Cobalt-chromium alloys offer improved radial strength and allow for thinner strut design while maintaining mechanical properties, as suggested by the European Society of Cardiology 2
The use of cobalt-chromium frames in transcatheter valves, such as the Edwards SAPIEN XT, enhances circularity and radial strength, according to the European Heart Journal 3, 2

The American College of Cardiology states that drug-eluting stents use the same metallic platforms as bare-metal stents (stainless steel or cobalt-chromium), which provide mechanical support to prevent vessel recoil and negative remodeling 1, 5
The metal scaffold in drug-eluting stents serves as a reservoir for controlled elution of antiproliferative agents, as noted by the American Heart Association 5
There are four FDA-approved drug-eluting stent types in the United States: sirolimus-eluting, paclitaxel-eluting, zotarolimus-eluting, and everolimus-eluting stents, as reported by the Circulation journal 1

The American College of Cardiology recommends the use of bioabsorbable polymers with antiproliferative drug coatings in newer drug-eluting stents, which eliminate long-term polymer presence while maintaining drug delivery, as suggested by the Journal of the American College of Cardiology 6

Nitinol (nickel-titanium alloy) causes fewer MRI artifacts and is used in some stent applications, as noted by the Journal of the American College of Radiology 4
Elgiloy (cobalt-chromium-nickel alloy) is another option but may cause more imaging artifacts, according to the Journal of the American College of Radiology 4

The American College of Cardiology warns that all metallic stents carry thrombosis risk, with bare-metal stents requiring 30 days of dual antiplatelet therapy (DAPT) and drug-eluting stents requiring prolonged DAPT (minimum 6-12 months) due to delayed endothelialization from antiproliferative drugs 1, 8
Premature DAPT discontinuation increases stent thrombosis risk catastrophically (hazard ratio 161 for subacute thrombosis), as reported by the Praxis Medical Insights: Practical Summaries of Clinical Guidelines, but a more reliable source is needed to support this claim 8