Abstract 13337: Left Atrial Ejection Fraction by Cardiac Magnetic Resonance Imaging as a Predictor of Adverse Outcomes in Patients With Advanced Ischemic Cardiomyopathy

Background: The prognostic significance of cardiac magnetic resonance (CMR) based left atrial ejection fraction (LAEF) is not well defined in the ischemic cardiomyopathy (ICM) cohort.We assess the additive effect of LAEF in a model to predict outcomes in patients with ICM. Methods: Patients with ICM, who underwent CMR between April 2001 and March 2019 were retrospectively included. Clinical characteristics and CMR parameters were collected and analyzed and LAEF was calculated in addition to myocardial infarct size (MIS) using late gadolinium enhancement (LGE) and CMR based mitral regurgitant fraction (MRF). The primary clinical endpoint was a composite of all-cause mortality and cardiac transplant. A multiple-variable Cox proportional hazards regression model which included established predictors of outcome was constructed, followed by the addition of LAEF. Four pre-specified interactions of LAEF with left ventricular end systolic volume index (LVESVi), MIS and mitral regurgitant fraction (MRF) were tested at a significance level of 0.05. RESULTS: LA functional data was measured in 718 patients. There were 416 deaths and/or transplants, with a median duration of follow up of 1763 days (4.8 years) The mean LA EF was 36 [2 ,74]. In univariate analysis, lower LAEF and higher LAVI were significant predictors of worse outcome, HR= 0.12, 95% CI [0.06, 0.25], p<0.001; HR 1.008, (1.003-1.014) p = 0.003. After addition to the multivariable model, a normal LAEF was highly predictive of reduced risk, HR 0.24, (0.12, 0.48), p<0.001. In the interaction between LAEF and MIS with MR Fraction, the highest risk was observed in patients with an LAEF < 20% and an MIS of > 30%, with MR Fraction of >35%, HR of 3.2 (1.73-5.93), p= 0.009. The lowest risk was in patients with an LAEF of >50% with an MIS of <15 and MR Fraction of <35%, HR 1.07 (0.81-1.42), p=0.009. Figure 1. CONCLUSION: Reduced LAEF is an important predictor of increased mortality in patients with ICM and additive to MIS and MR Fraction.