Abstract 15154: T1-mapping and Outcomes in Non-ischemic Cardiomyopathies- An Investigator-led Multicenter Observational Longitudinal Study

Abstract

Introduction: Nonischemic cardiomyopathy (NICM) is a recognised cause of poor clinical outcome. NICM is characterised by intrinsic myocardial impairment, which is driven by interstitial myocardial fibrosis in a considerable majority of NICM. The lack of accurate and noninvasive characterisation of interstitial myocardial fibrosis limits recognition of disease and effective clinical management in NICM. Hypothesis: T1 mapping by CMR is a novel non-invasive imaging application with a recognized potential to significantly improve the management of patients with NICM, supporting characterization of interstitial myocardial disease, assessment of severity of disease, risk stratification as well as development of targeted therapies. Comparative prognostic relevance of T1-mapping parameters in subjects with NICM for adverse outcome is unknown. Methods: an investigator-led multicenter observational longitudinal study in patients with NICM. We standardized imaging acquisition based on the modified Look-Locker sequence (MOLLI) (3(3)3(3)5) and post-processing approach of T1 mapping, and transferred the methodology to several other centres. We determined reference ranges for T1 mapping values and provided proof of concept studies in NICM in discrimination between health and disease. The primary endpoint was all-cause mortality. Results: 805 consecutive patients (mean age (years) 50±16; males: n=499, 62%) with NICM underwent contrast-enhanced CMR with T1-mapping. During a median follow-up period of 17 months (range 36 months), we observed a total of 26 deaths (18 cardiac). Native T1, ECV and extent of LGE were strongly associated with an increased likelihood of all-cause mortality (p<0.001). In multivariate analyses, native T1 was the sole independent predictor of all-cause and cardiac mortality, over and above ECV and LGE. Native T1 was also superior in correctly classifying subjects and adverse events over a 17-months period. Conclusions. In patients with NICM, non-invasive measures of interstitial myocardial fibrosis are useful in prediction of outcome. Native T1 is an independent predictor over and above conventional markers of risk, providing a basis for a novel algorithm of risk stratification in NICM.