LGE and NT-proBNP Identify Low Risk of Death or Arrhythmic Events in Patients With Primary Prevention ICDs

Abstract

The aim of this study was to investigate whether late gadolinium enhancement (LGE) magnetic resonance imaging or N-terminal pro-B-type natriuretic peptide (NT-proBNP) could identify patients with a low risk of death or use of implantable cardioverter-defibrillator (ICD) in patients receiving a primary prevention ICD. ICDs reduce mortality in patients with heart failure (HF), although two-thirds may never use their device. Current risk stratification, based on New York Heart Association functional class and left ventricular ejection fraction, still leads to implantation of ICDs in patients who may never need their device. We examined 157 patients with HF (61 with ischemic cardiomyopathy and 96 with dilated cardiomyopathy; mean age 50.5 years; 78% male) who underwent primary prevention defibrillator implantation. Presence and volume of LGE was measured before device implantation, and serum NT-proBNP level was measured before ICD implantation. The combined primary endpoint was cardiovascular death or appropriate ICD therapy (either appropriate shock or antitachycardia pacing). The primary outcome occurred in 32 patients (20.4%) over a median follow-up period of 915 days. Percentage of LGE (hazard ratio [HR]: per 1% increase: 1.06; 95% confidence interval [CI]: 1.04 to 1.09; p < 0.001) and (ln) NT-proBNP (HR: 1.44; 95% CI: 1.04 to 1.98; p = 0.027) were predictors of death or appropriate ICD activation and remained significant when entered into multivariable analysis. When the cohort was stratified into tertiles based on LGE percentage and NT-proBNP, we were able to identify a low-risk group (event rate 3% per year, compared with the intermediate- and high-risk groups [6% and 10% per year, respectively]). Both percentage of LGE and NT-proBNP were associated with higher risk of death or appropriate ICD activation. The use of these markers in combination may be useful in identifying individuals most likely to benefit from this costly intervention, and more specifically, in the identification of a group at lower risk in whom ICD implantation may be deferred.