The significance of surface changes on explanted polyurethane pacemaker leads.

Area of Science:

• Biomaterials Science
• Medical Device Engineering
• Cardiovascular Research

Background:

• Over 140,000 polyurethane leads are implanted in humans.
• Controversy exists regarding surface irregularities on explanted leads and their link to lead failure.

Purpose of the Study:

• To investigate the significance of surface irregularities on polyurethane leads.
• To assess the relationship between these irregularities and lead failure in a canine model.

Main Methods:

• Implanted atrial and ventricular polyurethane leads in dogs for 26-29 weeks.
• Removed leads using metered force or surgical extraction.
• Conducted physical testing (tensile strength, elongation) and scanning electron microscopy (SEM).
• Performed chemical analysis (X-ray, electron emission spectroscopy) and immersion in sodium hydroxide.

Main Results:

• No significant relationship found between physical testing results and extraction force, lead size, integrity, location, or SEM scores.
• Polyurethane insulator disconnected from the electrode in some forcibly removed leads.
• Chemical analysis did not reveal protein adsorption or liquid impregnation.
• SEM irregularities were observed in samples soaked in sodium hydroxide.

Conclusions:

• A clear link between chronic surface irregularities and polyurethane lead function, integrity, or strength has not been established in this short-term study.
• The potential time-dependent impact of these surface changes on lead performance remains unevaluated.
• The long-term clinical efficacy of polyurethane pacing leads requires further investigation.