NCDR Study Assesses ICD Device Therapy in Real-World Population

Device therapy for patients receiving primary prevention ICDs may vary across demographic and clinical characteristics, but may not be significantly different for patients in three subgroups the Centers for Medicare and Medicaid Services (CMS) has identified for further study, according to a study published in the Journal of the American Heart Association.

In 2005, CMS issued a “Coverage With Evidence Development” decision that established a national registry of patients receiving primary prevention ICDs to address knowledge gaps in patient selection and clinical decision-making. Three subgroups were identified for further study: patients with left ventricular ejection fraction of 31 percent to 35 percent; those with nonischemic dilated cardiomyopathy of less than nine months; and patients with NYHA class IV heart failure symptoms with a cardiac resynchronization therapy defibrillator (CRT-D). In an effort to assess these subgroups, Robert T. Greenlee, PhD, MPH, et al., used data from ACC’s ICD Registry and electronic health records to follow 2,540 patients who underwent ICD implantation between 2006 and 2009 for up to three years. Therapies were classified as appropriate when in response to a potentially malignant ventricular tachyarrhythmia and as inappropriate when attributable to other causes, including supraventricular arrhythmias or problems with device sensing or function.

According to the results, 29.1 percent of patients (738) experienced at least one episode that led to a device-related therapy during the median follow-up of 27 months. The researchers classified 55 percent of therapies as appropriate and 30 percent as inappropriate. Another 15 percent were considered unclassifiable based on available clinical information. Men and patients with a history of ventricular tachycardia were more than twice as likely to receive appropriate therapies. Patients with atrial fibrillation were more than twice as likely to have inappropriate therapies. In addition, the rate of inappropriate therapies was lower for participants who were 65 years or older and for those who received an ICD in 2009 vs. 2006. The adjusted rate of inappropriate therapy was lower among patients who received a CRT-D. The adjusted rates of both appropriate and inappropriate therapies were similar for the three CMS subgroups.

Therapy rates among the three CMS subgroups did not differ significantly when compared with the broader population, the researchers conclude. They add that their results provide “useful prognostic data for the growing population of patients treated with ICDs,” and “also offer policy stakeholders confidence in the coverage expansion decisions originally made on the basis of the select populations of randomized clinical trials.”

Keywords: National Cardiovascular Data Registries, ICD Registry, Cardiac Resynchronization Therapy, Atrial Fibrillation, Centers for Medicare and Medicaid Services, U.S., Cardiomyopathy, Dilated, Stroke Volume, Tachycardia, Ventricular, Defibrillators, Implantable, Primary Prevention, Heart Failure, Registries

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