Norepinephrine levels in children with single ventricle circulation

Abstract

Elevated plasma norepinephrine levels are a strong independent predictor of mortality in adults with heart failure with systolic dysfunction, and provide the mechanistic basis to its therapeutic paradigm. The pathogenesis of heart failure in the single ventricle circulation is unknown. It remains controversial whether conventional neurohormonal blockade in this population is beneficial. We hypothesize that norepinephrine levels can be elevated in children with single ventricle circulation and that it is associated with a poor outcome.Norepinephrine levels were collected from 22 consecutive single ventricle and 7 control patients at the time of catheterization. The disease group was followed for the development of heart failure and a composite outcome of death or transplant.Median age at norepinephrine level was 2.4years (interquartile range 93days–16.8years) and follow-up duration was 9.8years (range 75days–10.5years), during which 5 patients (23%) met a composite outcome of either death (n=4) or transplantation (n=1). While ventricular dysfunction and individual invasive hemodynamic parameters were not predictive of subsequent composite outcome, a norepinephrine level >369pg/mL at time of catheterization was associated with a decreased freedom from the composite outcome.In this study of children with single ventricle circulation, elevated norepinephrine levels were observed and were associated with a poor outcome. Consideration should be given to the further study of the role of neurohormonal activation and potentially its blockade, currently used for heart failure from systolic dysfunction, in the management of this high risk congenital heart disease population.