Thrombogenicity of biodegradable metals

Area of Science:

• Biomaterials Science
• Cardiovascular Engineering
• Materials Science

Background:

• Biodegradable metals offer an alternative to biostable metals in vascular devices, potentially reducing long-term risks.
• Current drug-eluting stents carry a significant risk of long-term thrombosis.
• The hemocompatibility and thrombogenicity of biodegradable metals are largely unknown.

Purpose of the Study:

• To evaluate the hemocompatibility and thrombogenicity of pure biodegradable metals (Fe, Zn, Mg, Mo) and common cardiovascular alloys (NiTi, CoCr, SS).
• To investigate the activation of platelets, coagulation factors, and inflammation by these metals.
• To assess the potential of biodegradable metals for use in vascular stents.

Main Methods:

• In vitro hemocompatibility assays were performed.
• An ex vivo non-human primate arteriovenous shunt model was utilized.
• Platelet activation, coagulation factor activation, and fibrin attachment were measured.

Main Results:

• All tested metals promoted downstream activation of platelets and coagulation in flowing whole blood.
• Magnesium (Mg) exhibited markedly reduced platelet and fibrin attachment.
• Iron (Fe) and Molybdenum (Mo) showed trends toward higher platelet attachment and contact pathway activation.

Conclusions:

• Magnesium may delay, but not eliminate, clot initiation, highlighting the need for further thrombosis research in Mg alloys.
• Understanding the blood reactivity of biodegradable metals is critical for the development of safer cardiovascular devices.
• These findings are crucial for the clinical translation of biodegradable metal stents.