The NCDR® ICD Registry™ Version 2.0: Update and Inclusion of Pediatric ICDs and Implanted Leads

The NCDR® ICD Registry™ Version 2.0: Update and Inclusion of Pediatric ICDs and Implanted Leads
The NCDR® ICD Registry™ Version 2.0: Update and Inclusion of Pediatric ICDs and Implanted Leads
The NCDR® ICD Registry™ Version 2.0: Update and Inclusion of Pediatric ICDs and Implanted Leads
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Author(s): 

Mark S. Kremers, MD, FACC; Christine Lang RN, MSN*, Associate Director, ICD Registry; and Stephen C. Hammill, MD, FHRS†
Mid Carolina Cardiology, Charlotte, NC; *American College of Cardiology, Washington, DC; †Mayo Clinic, Rochester, Minnesota

In this article, the authors discuss the new ICD Registry Version 2.0 launch on April 1, 2010.

In January 2005 the Centers for Medicare and Medicaid Services (CMS) expanded the covered indications for primary prevention implantable cardioverter defibrillators (ICDs) to incorporate the findings from the recently published Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT) and the Multicenter Automatic Defibrillator Implantation Trial II (MADIT II). As part of this expansion, CMS mandated that a national registry be formed to compile data on Medicare patients implanted with primary prevention ICDs to confirm the appropriateness of ICD utilization in this patient population. Responding to this mandate, a collaborative effort of the Heart Rhythm Society (HRS) and the American College of Cardiology Foundation (ACCF), utilizing the expertise of the National Cardiovascular Data Registry (NCDR®), developed Version 1 of the ICD Registry™. CMS selected the NCDR ICD Registry as the mandated national registry in October 2005 and enrollment opened on January 1, 2006. In April 2006, QNet (the temporary repository that had been accruing data since the initial ruling) was closed and the NCDR’s ICD Registry became the sole repository of ICD implant data on Medicare recipients. The initial registry design, Version 1, contains 159 data elements and is heavily focused on the patient and the procedure. Data is submitted by centers on a quarterly basis and must pass a data quality report (DQR) to ensure accuracy and completeness to be entered into the database. An on-site audit of a sample of records from randomly selected hospitals is also performed to ensure accuracy.

As of February 2010, Version 1 of the ICD Registry has accrued about 470,000 records and is adding about 10,000 implants a month. About 77% of the 1,500+ centers implanting ICDs in the U.S. have chosen to enroll all of their ICD implants (Premier Centers), not just Medicare primary prevention cases (CMS Limited Centers). The Premier Centers enroll about 91% of the total number of implants tracked by the registry (Table 1); thus, the data set is broad-based and representative of the larger clinical spectrum of ICD implants beyond just primary prevention in older patients. As such, it provides insights into this clinical arena that were previously impossible. The ICD patient population thus far entered into the data set has a mean age of 68. Three out of four recipients are men, 5 out of 6 are Caucasian, and 2 out of 3 have coronary heart disease. The implants are for primary prevention in over 75%. ICDs are single chamber in about 20%, dual chamber in 40%, and 40% are cardiac resynchronization therapy (CRT) devices (Table 1). About 25% of the devices are replacements. This rich data set has served as the basis for several important abstracts and manuscripts about ICD implants, including the impact of gender on ICD utilization and outcomes,1 and the role of physician training on appropriateness of device use and complications of implants.2 The data collection also fosters utilization of the registry as a quality tool for benchmarking outcomes of hospitals and physicians on both a local and national basis.3 Participating institutions receive detailed quarterly reports on their data comparing it to the national data set, as well as comparable institutions based on implant volumes. These reports can highlight areas for improvements and promote constructive changes in the quality and cost of ICD implantation.

Therefore, Version 1 of the ICD Registry has successfully fulfilled its initial mandate and its utility has extended beyond its inaugural vision. Nonetheless, it was recognized that there were omissions in the original data set that left some important information unavailable. The need for a second version was recognized early after release of Version 1. Development of Version 2.0 has been under way over the past 18 months to correct these oversights, clarify some data issues, and delete some rarely used data elements. In addition, the Pediatric and Congenital Electrophysiology Society (PACES) approached the registry with the request that the registry be expanded to include data elements specific to the pediatric population. The potential value of the registry as a powerful tool to track implanted lead technology was also recognized by the FDA. Thus, Version 2.0 also includes a new section on leads utilized in ICD systems.

Pediatric ICD implantations are estimated to constitute <1% of the volume of total ICD implantations.4 Thus far, with no provision in Version 1 for specific data elements appropriate for a pediatric population, implants in individuals less than 18 years of age have numbered <800 of the more than 470,000 implants (0.2%). This small number likely not only reflects the inadequacy of Version 1 for appropriately characterizing the pediatric patient, but also suggests the potential value of the ICD Registry to this patient population. Because of the relatively small number of implants and the diversity of congenital and genetic arrhythmic syndromes in which ICDs are utilized, large randomized controlled studies to assess ICD utility are unavailable and unlikely to be performed. Therefore, experimental data in this patient population is sparse. The ICD Registry, while not a clinical study with a control arm and strict inclusion and exclusion criteria, will still yield important information. The large numbers of patients accrued can give a real world insight into clinical issues. As ICDs were developed for, and validated in adult populations, the information derived from Version 2 of the ICD Registry will provide valuable insights into the risk and benefits of this therapy in the unique pediatric population.

The addition of pediatric data elements impacts the original registry data set to only a minor degree. However, the Version 2.0 data set has grown from 159 data elements to 298, largely due to the addition of data on ICD leads. Leads involved in ICD systems include: standard pacing electrodes in the right atrium (and rarely the right ventricle); right ventricular defibrillation leads that are complex multi-electrode leads used to sense, pace and deliver high energy shocks; and specially-designed small diameter pacing electrodes for introduction into the coronary venous anatomy for pacing the epicardial surface of the left ventricle. Other epicardial hardware or subcutaneous electrodes are infrequently incorporated in systems in patients with challenging anatomy or electrophysiology. In contrast to ICD pulse generators that are typically superficially implanted and have an anticipated obsolescence due to battery depletion, endovascular lead hardware has a potential service life that may approximate that of the patient. The leads’ structural complexity, the mechanical stresses of millions of cardiac contractions and upper body movement, and chemical interactions with body fluids threaten long-term lead integrity. Service life declines with time, and beyond 10 years is significantly impaired.5 Meanwhile, chronic fibrosis to fragile cardiovascular structures makes extraction potentially hazardous contributing to retention of non-functional hardware and accumulation of leads over time. This impacts vein patency and future lead implantation. Unfortunately, despite bench testing and clinical investigation in hundreds of patients over relatively short time frames, lead issues may only become manifest after many thousands of implants and years of service.6 Therefore, it is not surprising that leads are considered the weak link in ICD systems.7 Thus, in the hopes of improving post market surveillance, the FDA has assisted the ICD Registry with adding elements to Version 2.0 to allow assessment of lead performance.

At Premier Centers only, all leads utilized in ICD systems will be tracked at implantation, revision, removal, or abandonment. Placement issues, functionality, and structural integrity will be assessed at all ICD surgical procedures even if the leads are not manipulated. In Version 1, implantation of an ICD generator triggered entry into the registry. However, now lead-only related procedures will also be tracked at Premier Centers and a second shorter data form has been developed to address these procedures specifically (Figure 1). Despite implantation of an ICD as the threshold for data submission, Version 1 is mostly focused on the patient and procedure. Very little data is acquired about the ICD itself and product performance is not a significant focus. The inclusion of lead data will therefore not only substantially increase the volume of data acquired, but broaden the focus of the registry to include product performance as a major outcome. The new data elements have been selected specifically to address this goal.

Lead data acquisition via the registry confers potential advantages to that of other databases. Calculating for device replacements, there are an estimated 350,000 defibrillation leads implanted in registry recipients. Based on the distribution of device types, total leads implanted exceed an estimated 750,000. This enormous volume holds the potential to serve as an early detection system for lead performance issues and potentially detect lead problems at a level not possible with smaller numbers. The non-proprietary basis of the registry will eliminate bias and non-clinical considerations that could cloud data analysis.8 Manufacturer-based lead follow-up is partially limited by returned product analysis that includes products damaged in the extraction process, and underreporting of leads that are physically abandoned or functionally abandoned by programming. These data sets, however, will include some data on products from international markets and from the CMS limited implantation sites that will not track leads in the registry. With the advent of Internet-based remote follow-up systems, these databases will also have the potential to accrue serial data on lead performance. Thus, the ICD Registry will likely be complementary to other data sets, and in combination will give a truer picture of lead performance over time. Simple data accrual in the registry, however, is not sufficient to improve detection and understanding of lead performance issues. Methods and means for data surveillance and analysis must be developed to exploit this opportunity. The FDA and the NCDR are actively exploring these issues. The data will also be available, via an established process, to investigators who request access to address specific questions.

Version 2.0 of the ICD Registry is scheduled to go live in April 2010 after a preview introduction at the NCDR Annual Meeting in Atlanta. Like Version 1, implementation of Version 2.0 may expose further imperfections in the data set and room for future improvement. However, the opportunity to learn from ongoing experience and improve the quality of care for ICD recipients has never looked so promising.

References: 

1. Peterson PN, Daugherty SL, Wang Y, et al. Gender differences in procedure-related adverse events in patients receiving implantable cardioverter-defibrillator therapy. Circulation 2009;119:1078-1084. 2. Curtis JP, Luebbert JJ, Wang Y, et al. Association of physician certification and outcomes among patients receiving an implantable cardioverter-defibrillator. JAMA 2009;301:1661-1670. 3. Hammill SC, Kremers MS, Kadish AH, et al. Review of the ICD Registry's third year, expansion to include lead data and pediatric ICD procedures, and role for measuring performance. Heart Rhythm 2009;6:1397-1401. 4. Berul CI, Van Hare GF, Kertesz NJ, et al. Results of a multicenter retrospective implantable cardioverter-defibrillator registry of pediatric and congenital heart disease patients. J Am Coll Cardiol 2008;51:1685-1691. 5. Kleemann T, Becker T, Doenges K, et al. Annual rate of transvenous defibrillation lead defects in implantable cardioverter-defibrillators over a period of >10 years. Circulation 2007;115:2474-2480. 6. Hauser RG, Hayes DL. Increasing hazard of Sprint Fidelis implantable cardioverter-defibrillator lead failure. Heart Rhythm 2009;10:605-610. 7. Maisel WH. Transvenous implantable cardioverter-defibrillator leads: The weakest link. Circulation 2007;115:2461-2463. 8. Maisel WH, Hauser RG. Proceedings of the ICD Lead Performance Conference. Heart Rhythm 2008;5:1331-1338.


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