Latest National ICD Registry captures data of about “90% of all ICDs implanted in the USA”

Mark Kremers
Mark Kremers

On 12 March, the Heart Rhythm Society (HRS) and the American College of Cardiology Foundation (ACCF) released the National implantable cardioverter defibrillator (ICD) Registry Report: Version 2.1. The new version expands upon version 1 of the US ICD Registry 2009 Annual Report including data of about 90% of all ICDs implanted in the USA in 2010 and 2011. Cardiac Rhythm News spoke to Mark S Kremers, chairman, ICD Registry Steering Committee, on the results from the latest registry.

What was the objective of this registry?

The ICD Registry was mandated by the Center for Medicare and Medicaid Services in 2005 to determine the extent to which Medicare Primary Prevention implantable cardioverter defibrillator (ICD) utilisation in the real world was consistent with indications based on criteria from published randomised controlled trials. A recent publication in the Journal of the American Medical Association (JAMA) by Dr Sana Al Khatib of Duke University (JAMA 2013; 309:55-62) has used registry data to address that question with affirmative results.

Why is this registry important in clinical practice in the USA?

Even though the registry is mandated for only Medicare Primary Prevention patients, about 80% of the 1,700+ centres enrolling patients in the registry have chosen to submit data on all of their patients. Thus about 90% of all ICDs implanted in the USA are tracked. This is an incredible source of clinical (not administrative) data that allows us to better understand contemporary ICD utilisation, track changes over time, and improve the decision making and processes of care that impact the quality and cost of care this population receives. Thus it is both a quality improvement tool and an incredible source of research data.

This new version highlights the inclusion of data on leads and paediatric implants. What are the key findings from these data?

The leads data largely confirm known issues with a couple of underperforming leads but also allows a real world look at how these problems with leads are being dealt with. It also underscores the huge base of implanted technology (totaling >550,000 leads) in the ~260,000 patients. Leads are technologically complex and must deal with consider mechanical and biological stresses, challenging their long term performance. The registry and the FDA hope that tracking the large volumes of leads entered into the registry will potentially provide an early signal source for lead problems should they develop in the future.

There are too few paediatric implants (<400) as yet to draw major conclusion but the registry has great potential for informing the paediatric EP world about these challenging cases by aggregating data from many sources.

Can you summarise key general findings?

  • Implants continue to grow but there is a shift to more complex devices and more replacements.
  • Complications continue to trend in a favourable direction.
  • New implant volume may in fact be stabilising or even decreasing.
  • Based on the large base of implanted leads and recognised performance issues, lead management issues will remain with us in the future.

What are the differences found compared to the results obtained from the version 1 of the registry (2006–2009)?

More complete and accurate representation of the population by the addition of new data elements allowing a truer picture of care and capturing more completely a larger number of implants.

According to this new report, some concerns have been raised, for example, inappropriate device use and that ICD’s are underused in some populations. Could you explain further these issues and also tell us about other concerns raised?

One study (Al Khatib
et al; JAMA 2011; 305:43-49) has suggested about one in four to five ICDs are implanted outside of guideline indications. This is not however synonymous with unnecessary or inappropriate utilisation. Some were very likely appropriate based on a different view of the indications and some may simply be in areas with insufficient data upon which to accurately judge appropriateness. Alternatively, based on populations of patients post myocardial infarction and with heart failure, one can estimate that more patients are potentially eligible for ICDs than actually get them. Additionally there are recognised demographic variances, including race and gender, that impact device utilisation. A Department of Justice investigation into ICD utilisation and the concern raised about use of ICDs outside guideline indication may unfortunately have exacerbated the problem of underuse. An appropriate use criteria document just published (JAm Coll Cardiol 2013; 61:1323-73) promises to enlighten us further as to what are the clinically reasonable circumstances in which to consider device utilisation. However, as funding of ICDs is tightly tied to the Medicare National Coverage Determination, much work remains to be done to align medical decisions about device implants and the economic decisions to support funding for those implants.

Mark S Kremers is from Mid Carolina Cardiology, Charlotte, North Carolina, USA.