Prevalence and predictors of off-label use of cardiac resynchronization therapy in patients enrolled in the National Cardiovascular Data Registry Implantable Cardiac-Defibrillator Registry

Abstract

Objectives: The purpose of the study was to define the extent and nature of cardiac resynchronization therapy (CRT) device usage outside consensus guidelines using national data.

Background: Recent literature has shown that the application of CRT in clinical practice frequently does not adhere to evidence-based consensus guidelines. Factors underlying these practices have not been fully explored.

Methods: From the National Cardiovascular Data Registry's Implantable Cardiac-Defibrillator Registry, we defined a cohort of 45,392 cardiac resynchronization therapy-defibrillator (CRT-D) implants between January 2006 and June 2008 with a primary prevention indication. We defined "off-label" implants as those in which the ejection fraction was >35%, the New York Heart Association functional class was below III, or the QRS interval duration was <120 ms in the absence of a documented need for ventricular pacing. The relationships between patient, implanting physician, and hospital characteristics with off-label use were explored with multivariable hierarchical logistic regression models.

Results: Overall, 23.7% of devices were placed without meeting all 3 implant criteria, most often due to New York Heart Association functional class below III (13.1% of implants) or QRS interval duration <120 ms (12.0%). Atrial fibrillation/flutter, previous percutaneous coronary intervention, and the performance of an electrophysiology study before implant were independently associated with increased odds of off-label use, whereas diabetes mellitus, increasing age, and female sex were associated with decreased odds. Physician training and insurance payer were weakly associated with the likelihood of off-label use.

Conclusions: Nearly 1 in 4 patients receiving CRT devices in the study time frame did not meet guideline-based indications. Given the evolving evidence base supporting the use of CRT, these practices require careful scrutiny.

Figure 1. Derivation of Study Cohort

Flow diagram showing the derivation of the study cohort of patients receiving first-time cardiac resynchronization therapy-defibrillator (CRT-D) implants for primary prevention indications. ACC/AHA = American College of Cardiology/American Heart Association; EF = ejection fraction; ICD = implantable cardiac-defibrillator; NYHA = New York Heart Association; VT = ventricular tachycardia.

Figure 2. Time Trends for CRT-D Implants in NCDR ICD Registry

Time trends for cardiac resynchronization therapy-defibrillator (CRT-D) implants in the National Cardiovascular Data Registry (NCDR) Implantable Cardiac Defibrillator (ICD) Registry from January 2006 through June 2008. In each quarter examined, the proportion of implants defined as off-label (blue bars) ranged from 27% to 29%. Note that the appearance of growth in overall procedural volume from the first quarter to the second quarter of 2006 is likely due to incomplete data for Q1, 2006, the first quarter of data entry into the registry, rather than actual changes in procedure rates. The orange bars indicate on-label implants.