A STUDY OF IMPLANTABLE CARDIAC DEVICE ELIGIBILITY, UTILIZATION AND REASONS FOR NON-IMPLANTATION IN PATIENTS AT HEART FUNCTION CLINICS

Abstract

Despite evidence and guideline recommendations, there is a presumptive underutilization of implantable cardioverter defibrillator (ICD) therapy in patients with heart failure (HF) even when seen by specialists. The primary aim of this study was to determine the rates of ICD eligibility and utilization among patients seen at heart function clinics (HFC). Secondary aims were to identify reasons for non-implantation among eligible patients and to determine predictors of non-implantation. As part of the EP Expert Working group of the Cardiovascular Strategic Clinical Network, we performed a retrospective review of consecutive patients seen at two HFCs in Alberta from 2013-2015. A detailed chart review was performed to collect demographics, clinical indications, comorbidities and to identify reasons for non-implantation. Eligibility for an ICD was determined using the 2008 ACC/AHA/HRS ICD guidelines and the 2013 CCS CRT guidelines. Patients were considered “guideline eligible” if they met the following criteria; left ventricular ejection fraction (LVEF) ≤0.35, New York Heart Association (NYHA) Class I-III and an absence of either revascularization within 3 months or acute myocardial infarction within 40 days of determined device eligibility. Logistic regression was used (odd ratio, OR and 95% CI) to identify predictors of device non-implantation. Overall, 1239 unique patients were seen in a HFC, the majority were male (66%), the median age was 70 (IQR 59-80) and the median LVEF was 0.4 (IQR 0.28-0.53) Over the follow-up period, 55% of patients were never eligible for device therapy based on LVEF and NYHA criteria. Yearly rates of eligibility ranged from 32-37% and yearly rates of device utilization among eligible patients ranged from 19-34% (Figure 1). When a reason for non-implantation was accounted for, yearly utilization rates increased to 36-50%. Among eligible patients, independent predictors of device non-implantation were age >75 years (OR 1.90, 1.29-2.82), LVEF ≤0.35 (OR 3.50, 1.98-6.17) and cancer (OR 2.22, 1.04-4.74). In nearly half of the cases (n=283, 46%), no clear documented reason for non-implantation was found. When a reason was documented, it was most commonly patient preference (25%), technical reasons (19%) and medical reasons (10%). We found that less than half of eligible patients received an ICD even when seen by specialists in a HFC and a reason for non-implant was often missing. Appropriate ICD utilization could be improved with initiatives aimed at screening high-risk individuals, along with requirements for documentation on reasons for non-eligibility.