Challenges in Cardiac Implantable Electronic Device Surveillance: Insights from Real-World DataGeorge S. Prousi, MD and Pamela K. Mason, MDUniversity of VirginiaCorresponding author:Pamela K. Mason, MDBox 800158Charlottesville, VA 22908434-924-2465Fax: 434-982-1998Pkm5f@virginia.eduDisclosures:Mason- Consulting and honoraria for Medtronic and Boston ScientificProusi- NoneCardiac implantable electronic devices (CIEDs), including permanent pacemakers (PPMs), implantable cardioverter-defibrillators (ICDs) and cardiac resynchronization therapy (CRT) devices have improved patient outcomes for a variety of cardiovascular conditions.1,2 There is an upward trend in the utilization of CIEDs due to multiple variables including an aging population with increased comorbidities and expanded indications.3 CIED technology has rapidly evolved and device components must undergo rigorous evaluation to ensure safety and efficacy. Despite pre-market testing and post-market surveillance, historically, there has been an underestimation of device and lead failures.4 It is well known that transvenous leads are the “weak link” in most CIED systems, and efforts to reduce CIED malfunctions must address this issue.To improve the reliability of transvenous leads, design and manufacturing has included a focus on insulation integrity. Optim™, a co-polymer of silicone and polyurethane is a form of insulation incorporated into the Abbott Tendril™ STS 2088TC (Tendril 2088) leads. It was developed with an aim to reduce the risk of lead abrasion. There have been several studies suggesting an accelerated degradation of materials and lead failure for leads using Optim™, and particularly the Tendril 2088 lead.5-7 However, most of the clinical studies are single-center and observational.In this edition of the Journal of Cardiovascular Electrophysiology, Ahmed et al. used an analytic real-world data model to compare the Tendril 2088 lead to pacing leads manufactured by competitors. This model uses patient device tracking, the Abbott device registration database, and the Medicare-fee-for-service database, and it has been validated previously.8 Probablistic linking was used to link the patients who were implanted with Tendril 2088 leads from the Abbott registry to the Medicare database. The authors then compared the rates of Tendril 2088 mechanical lead malfunction resulting in lead-related surgical intervention to competitors’ pacing leads. The numbers are substantial, with 89,629 Tendril 2088 leads identified compared to 433,481 competitive manufacturer leads. The groups were demographically similar, and the follow-up period was a minimum of two years. This real-world data analysis revealed no significant difference in surgical intervention-free survival rates between the two groups.The findings of this study present a contrast from other studies that suggested that there may be an increased risk of Tendril 2088 lead failures as compared to competitors’ pacing leads. The authors outline potential reasons for this variance, which include sample size, possible bias within the populations, and how “lead failure” is defined. This study had a rigorous definition of failure which needed surgical intervention but may not completely reflect all failure presentations and the effect on patient outcomes. This serves as a reminder of the challenges in product evaluation and surveillance.The authors have offered important insights into the Abbott Tendril 2088 lead, although evaluation of the Tendril 2088 lead and the Optim™ insulation will be ongoing.7 They also should also be congratulated for showing the added value of a real-world data model in post-market product monitoring. With these models, sample sizes can more accurately and expeditiously identify occurrences of device related malfunction and capture a wider range of patient demographics.Device manufacturers and the electrophysiology community are continually developing ways to analyze and follow products for safety and reliability. It is clear that the traditional methods of pre-market studies and post-market registries are inadequate to identify product deficiencies. This is particularly true for more uncommon issues or ones that only occur in specific populations or circumstances. Manufacturers are adding simulation modeling data to their product evaluation to enhance the reliability of their data.9 The addition of real-world data is another substantial advancement.It is important to note that many CIED manufacturers are making efforts to move away from traditional stylet-driven transvenous leads.10 This is a simple acknowledgement that these leads are still the “weak link” in most device systems despite sophisticated engineering and aggressive surveillance. Lumen-less transvenous leads are available which are thought to be more durable. For ICDs, subcutaneous and extravascular leads are both lumen-less and do not use the vasculature. Finally, leadless pacemakers avoid the issue all together.Regardless of these advances, millions of patients have transvenous CIED systems in place and these systems will continue to be the major mode of providing CIED therapies into the near future. We need robust mechanisms to follow all CIED products and real-world data models will play a role. Though there will be further question about the reliability of Tendril 2088 leads, there should be no dispute over the united pursuit for early identification of device related malfunctions and the use of large-scale data to achieve the best possible outcomes for our patients.Kusumoto FM, Schoenfeld MH, Barrett C, et al. 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay: Executive summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines, and the Heart Rhythm Society. Heart Rhythm. 2019;16:e227-e279.Al-Khatib SM, Stevenson WG, Ackerman MJ, et al. 2017 AHA/ACC/HRS Guideline for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. J Am Coll Cardiol. 2018;72:e91-e220.Greenspon AJ, Patel JD, Lau E, et al. . Trends in permanent pacemaker implantation in the United States from 1993 to 2009: increasing complexity of patients and procedures. J Am Coll Cardiol. 2012;60:1540-5.Roberts H, Matheson K, Sapp J, et al. Prevalence and management of electrical lead abnormalities in cardiac implantable electronic device leads. Heart Rhythm O2. 2023;4:417-426.Segan L, Samuel R, Lim M, et al. Incidence of Premature Lead Failure in 2088 TendrilTM Pacing Leads: A Single Centre Experience. Heart Lung Circ. 2021;30:986-9956.Shah AD, Hirsh DS, Langberg JJ. User-reported abrasion-related lead failure is more common with durata compared to other implantable cardiac defibrillator leads. Heart Rhythm. 2015;12:2376-80.El-Chami MF. The saga of tendril leads continues: Should we continue to bury our heads in the sand? J Cardiovasc Electrophysiol. 2021;32:1122-1123.Braghieri L, Ahmed A, Curtis AB, et al. Evaluating cardiac lead safety using observational, real-world data: EP PASSION proof-of-concept study. Heart Rhythm. 2024;S1547-5271(24)02819-4.Crossley, George H.Sanders, Prashanthan et al. Safety, efficacy, and reliability evaluation of a novel small-diameter defibrillation lead: Global LEADR pivotal trial results 2024;S1547-5271(24)02395-6.Wiles BM, Roberts PR. Lead or be led: an update on leadless cardiac devices for general physicians. Clin Med (Lond). 2017;17:33-36.