Outcomes of Restrictive Cardiomyopathy in Childhood and the Influence of Phenotype: A Report from the Pediatric Cardiomyopathy Registry
Background—Restrictive cardiomyopathy (RCM) has been associated with poor prognosis in childhood. The goal of the present analysis was to use the Pediatric Cardiomyopathy Registry (PCMR) to analyze outcomes of childhood RCM, with focus on the impact of phenotype comparing ‘pure’ RCM to cases with additional features of hypertrophic cardiomyopathy (HCM).
Methods and Results—We analyzed the PCMR database (1990-2008; N=3375) for cases of RCM. Cases were defined as 'pure' when RCM was the only assigned diagnosis. Additional documentation of HCM at any time was used as the criteria for RCM/HCM phenotype. RCM accounted for 4.5% of cases of cardiomyopathy. In 101 (66%), pure RCM was diagnosed; in 51 (34%) there was mixed phenotype. Age at diagnosis was not different between groups, but 10% of the pure RCM group was diagnosed in infancy versus 24% of RCM/HCM. Freedom from death was comparable between groups with 1, 2, and 5 year survival of RCM 82, 80, 68% versus RCM/HCM 77, 74, 68%. Transplant-free survival was 48, 34, 22% and 65, 53, and 43% respectively (P=0.011). Independent risk factors at diagnosis for lower transplant-free survival were heart failure (HR 2.20, P=0.005), lower fractional shortening z-score (HR 1.12 per 1 SD decrease in z-score, P=0.014) and higher posterior wall thickness in the RCM/HCM group only (HR 1.32, P<0.001). Overall, outcomes were worse than for all other forms of cardiomyopathy.
Conclusions—Transplant-free survival is poor for RCM in childhood. Survival is independent of phenotype; however, the RCM/HCM phenotype has significantly better transplant-free survival.
Clinical Trials Registration Information—clinicaltrials.gov; Identifier: NCT00005391
- Received March 13, 2012.
- Accepted July 18, 2012.
- Copyright © 2012, American Heart Association, Inc. All rights reserved. Unauthorized use prohibited