End of Life Biocompatibility Assessment for Chronically Implanted Cardiac Leads

Area of Science:

• Biomaterials Science
• Medical Device Engineering
• Analytical Chemistry

Background:

• Medical device biocompatibility is crucial throughout its lifecycle.
• Current evaluations typically assess new devices, not long-term changes.
• Long-term implantable devices like cardiac leads require understanding lifecycle material behavior.

Purpose of the Study:

• To investigate changes in extractable species in human-implanted cardiac leads over time.
• To assess the impact of implantation duration on the chemical profile of cardiac leads.
• To evaluate the stability of biocompatibility for long-term implantable devices.

Main Methods:

• Analysis of extractables from human-implanted cardiac leads (3-130 months).
• Utilized liquid chromatography coupled to mass spectrometry (LC-MS) for identification and quantification.
• Performed exhaustive extractions to identify all mobile species.

Main Results:

• No new extractable species were formed over implant times exceeding a decade.
• The quantity of mobile species remained constant or decreased over the implantation period.
• Polyurethane oligomers stayed constant; antioxidant additives showed diffusional release, not reactive consumption.

Conclusions:

• The chemical profile of mobile species in cardiac leads does not change over the implanted lifecycle.
• The biocompatibility of durable cardiac leads is maintained over time.
• The assumption of complete release of extractables from new devices is overly conservative compared to in-vivo release rates.