Abstract 2343: Outcomes in Children with Noonan Syndrome and Cardiomyopathy
OBJECTIVE: The presence of cardiomyopathy in some children with Noonan syndrome (NS) has been well described. The objective of this analysis was to determine the survival experience of these children and to identify clinical and echocardiographic predictors of outcome.
METHODS: The Pediatric Cardiomyopathy Registry enrolled 69 patients with NS diagnosed with hypertrophic cardiomyopathy (HCM) and 834 children with other HCM between 1990 and 2003. Clinical, echocardiographic and outcome data were collected by chart review annually.
RESULTS: Over half (52%) of the 69 NS patients were diagnosed with HCM at <6 months of age and 26% had congestive heart failure at presentation. Children with NS had lower survival compared to children with other HCM (74% vs. 91% at 1 year; 69% vs. 84% at 5 years, p=0.004). Left ventricular dimension Z-scores increased (p<0.01) and septal wall thickness Z-score (p=0.037) and posterior wall thickness to end diastolic dimension ratio (p<0.001) decreased over time. A multivariate model for mortality found congestive heart failure symptoms (p=0.002), fractional shortening Z-score < 6.7 (p=0.043) and septal wall thickness Z-score ≥ 2.1 (p=0.018) at the time of cardiomyopathy diagnosis as independent risk factors. A multivariate model incorporating longitudinal echocardiographic measures demonstrated that diagnosis at age <six months (p=0.048), congestive heart failure at diagnosis (p=0.027), and septal wall thickness Z-score ≥ 2.1 (p=0.027) just prior to death were independent predictors of mortality. LV mass Z-score just prior to death was also predictive but correlated with wall thickness Z-score.
CONCLUSIONS: The majority of children with NS are diagnosed with cardiomyopathy before age 6 months and 26% have congestive heart failure at the time of diagnosis. One-quarter die within one year and almost one-third die within 5 years of diagnosis, a poorer outcome than that of children with other forms of HCM. Symptoms of heart failure and diagnosis before age 6 months, in combination with lower fractional shortening at presentation and increased septal wall thickness are predictive of poor outcome.