Abstract 9638: Left Atrial Volume Provides Independent and Incremental Prognostic Information in Non-Ischemic Dilated Cardiomyopathy

Abstract

Introduction: Echo data have shown that left atrial (LA) diameter and area predict adverse outcome in heart failure (HF) cohorts of mixed etiology. Since LA dilatation is asymmetric, LA volume (LAV) is a better measure of LA size. CMR allows more accurate measurement of LAV due to its superior spatial resolution and endocardial border definition. We hypothesized that CMR assessment of LAV provides independent and incremental prognostic information in non-ischemic dilated cardiomyopathy (DCM).

Methods: Consecutive patients with DCM referred for CMR between 2000-08 were prospectively enrolled. Patients with IHD, primary valvar disease and infiltrative CM were excluded. LAV was measured at LV end-systole by a single blinded specialist using the biplane area-length method and indexed to body surface area (LAVi). The primary endpoint was cardiovascular (CV) death or cardiac transplantation (CTx). The secondary endpoint was a composite of HF death, HF hospitalization or CTx.

Results: In total 483 patients (327 male, mean age 51 yrs, mean LVEF 37%) were followed up for a median duration of 64 months. There were 75 deaths (60 CV deaths) and 9 patients underwent CTx. ROC analysis identified that the optimal LAVi cut-off value for predicting the primary endpoint was 77 ml/m². Kaplan-Meier analysis demonstrated that patients with a LAVi>77 ml/m² had a significantly higher rate of CV death or CTx (p<0.001, Fig.1). After stepwise Cox regression multivariate analysis, LAVi remained a significant independent predictor of CV death or CTx (HR per 10 ml/m², 1.11, 95% CI 1.04 to 1.19; p=0.003) and the secondary HF composite (HR per 10 ml/m², 1.11, 95% CI 1.04 to 1.18; p=0.001), alongside conventional prognosticators such as LVEF and NYHA class.

Conclusions: LAV has independent and incremental prognostic value for the prediction of transplant-free CV survival and HF outcomes in DCM. Assessment of LAV improves risk stratification in DCM and should be incorporated into routine CMR examination.