Evaluation of the in vivo chemical reactivity of a novel copolymer insulation on cardiac leads in a single-center study

Rand Ibrahim; Kimberly Chaffin; Anand Shah; Stacy Westerman; Michael Lloyd; Neal Bhatia; Faisal M Merchant; Mikhael El-Chami

doi:10.1016/j.hrthm.2024.02.062

Evaluation of the in vivo chemical reactivity of a novel copolymer insulation on cardiac leads in a single-center study

Heart Rhythm. 2024 Mar 2:S1547-5271(24)00234-0. doi: 10.1016/j.hrthm.2024.02.062. Online ahead of print.

Authors

Rand Ibrahim¹, Kimberly Chaffin², Anand Shah¹, Stacy Westerman¹, Michael Lloyd¹, Neal Bhatia¹, Faisal M Merchant¹, Mikhael El-Chami³

Affiliations

¹ Department of Medicine, Division of Cardiology, Emory University School of Medicine, Atlanta, Georgia.
² Medtronic, Minneapolis, Minnesota.
³ Department of Medicine, Division of Cardiology, Emory University School of Medicine, Atlanta, Georgia. Electronic address: melcham@emory.edu.

PMID: 38437891
DOI: 10.1016/j.hrthm.2024.02.062

Abstract

Background: Human in vivo data on the chemical stability of different transvenous lead materials, particularly Optim^TM leads, are lacking.

Objectives: The purpose of this study was to determine the chemical reactivity of insulation materials by analyzing the molar mass of extracted pacing and defibrillator leads METHODS: We collected extracted leads at Emory University Hospitals and sent the leads with thermoplastic outer insulation material for molar mass analysis, a material characteristic that informs biostability. Leads were separated based on the chemical identity of the outer insulation material, and the molar mass was measured by an independent party. The extent of chemical reaction was compared across leads having different materials: poly(ether)urethane 55D, poly(ether)urethane 80A, and Optim.

Results: A total of 70 leads were extracted. The subset of extracted leads having outer insulation materials composed of PEU or Optim were analyzed for molar mass, where implant times ranged from 0.12 to 16.26 years. The rate of chemical degradation was compared by plotting the extent of reaction [M_n(t = 0)/M_n(t)] as a function of implant time. The Optim molar mass decreased to 40% of its initial value at 10 years of implant. No change in the molar mass of the PEU insulations could be resolved over the same 10-year implant time.

Conclusion: Because the molar mass of a polymer is directly related to its mechanical integrity, the observed decrease in molar mass of Optim likely translates into premature insulation defects and is consistent with the observed increased rate of electrical malfunction/noise in this subset of cardiac leads.

Keywords: Insulation defect; Lead extraction; Lead failure; Optim insulation; Polymer degradation.