RESUMEN
BACKGROUND: The presence of interstitial fibrosis and lipofuscin in endomyocardial biopsies may indicate the chronicity of heart failure. Fibrosis is known to increase in the failing heart. Lipofuscin increases with age, but its relationship to heart function is unknown. This study investigated whether lipofuscin or fibrosis had predictive utility in indicating function or adverse event (death, transplant, assist device placement) at 1 year postbiopsy in adolescents and young adults. METHODS: A retrospective analysis was performed on nontransplant endomyocardial biopsies between 2000 and 2009 from individuals aged 10-40 years. Clinical and demographic information including ejection fraction (EF), EF at 1 year, and adverse events were obtained as available. Lipofuscin and fibrosis were scored retrospectively in a blinded fashion for 201 biopsies. Linear regression and Cox proportional hazard models were used for multivariable analysis. RESULTS: Increasing lipofuscin strongly correlated with patient age (P<.0001). Higher lipofuscin levels were correlated with a better EF at 1 year (P=.02). This remained significant (P=.04) after adjusting for age. The degree of fibrosis did not associate with any clinical variable and had no predictive capabilities in this study. CONCLUSIONS: This is the first study to incorporate lipofuscin in predicting future heart function. We found that more lipofuscin correlates with better EFs at 1 year, suggesting that lipofuscin is a marker for improved cardiac compensation. This information can help clinicians devise treatment plans for individuals in this age group.