<p>Hypertrophic cardiomyopathy (HCM) is often caused by pathogenic variants in sarcomeric genes and characterized by left ventricular (LV) hypertrophy, myocardial fibrosis and increased risk of heart failure and arrhythmias. There are no existing therapies to modify disease progression. In this study, we conducted a multi-center, double-blind, placebo-controlled phase 2 clinical trial to assess the safety and efficacy of the angiotensin II receptor blocker valsartan in attenuating disease evolution in early HCM. In total, 178 participants with early-stage sarcomeric HCM were randomized (1:1) to receive valsartan (320 mg daily in adults; 80-160 mg daily in children) or placebo for 2 years ( NCT01912534 ). Standardized changes from baseline to year 2 in LV wall thickness, mass and volumes; left atrial volume; tissue Doppler diastolic and systolic velocities; and serum levels of high-sensitivity troponin T and N-terminal pro-B-type natriuretic protein were integrated into a single composite z-score as the primary outcome. Valsartan (n = 88) improved cardiac structure and function compared to placebo (n = 90), as reflected by an increase in the composite z-score (between-group difference +0.231, 95% confidence interval (+0.098, +0.364); P = 0.001), which met the primary endpoint of the study. Treatment was well-tolerated. These results indicate a key opportunity to attenuate disease progression in early-stage sarcomeric HCM with an accessible and safe medication.</p>
<p><strong>BACKGROUND: </strong>Durable ventricular assist devices (VADs) are increasingly used to treat children with heart failure. Studies demonstrate worse outcomes for those in cardiogenic shock at the time of VAD, but limited data exist on less acutely ill children. We describe the association between illness severity and outcomes in this population.</p>
<p><strong>METHODS: </strong>Data were analyzed from 373 children (aged <19 years) receiving durable VADs from 46 centers in the Pediatric Interagency Registry for Mechanical Circulatory Support. Outcomes were compared by Interagency Registry for Mechanical Circulatory Support (INTERMACS) Patient Profile (PP) and pre-implant characteristics using competing risks methodology.</p>
<p><strong>RESULTS: </strong>Analyses identified 97 patients in cardiogenic shock (PP 1), 222 with progressive decline (PP 2), and 42 stable on inotropes (PP 3). There were 39 infants, 124 were aged 1 to 9 years and 210 were aged 10 to 19 years. A majority had cardiomyopathy and 66 had congenital heart disease (CHD). There were 224 (62%) continuous-flow VADs. Before implant, 40% received mechanical ventilation (MV). Within 6 months post-implant, 57% underwent transplant and 14% died. PP 1 mortality was highest (25% vs 10% for PP 2, hazard ratio [HR]: 2.5, 95% CI: 1.4-4.4, p = 0.02). In PP 1, CHD was an independent mortality risk factor (HR: 2.9, 95% CI: 1.1-7.8, p = 0.03). In PP 2, pulsatile VADs were associated with death (HR: 3.9, 95% CI: 1.6-9.5, p = 0.003). Patients on MV had high mortality (20%-30%) across PP 1 to PP 3 (HR: 3.0 vs no MV, p < 0.001).</p>
<p><strong>CONCLUSIONS: </strong>Children in shock at the time of VAD implant have poor outcomes. MV is associated with increased mortality even in lower acuity INTERMACS profiles. Further study is needed to identify modifiable risk factors in this population.</p>
<p>Pediatric cardiomyopathies are rare diseases with an annual incidence of 1.1 to 1.5 per 100 000. Dilated and hypertrophic cardiomyopathies are the most common; restrictive, noncompaction, and mixed cardiomyopathies occur infrequently; and arrhythmogenic right ventricular cardiomyopathy is rare. Pediatric cardiomyopathies can result from coronary artery abnormalities, tachyarrhythmias, exposure to infection or toxins, or secondary to other underlying disorders. Increasingly, the importance of genetic mutations in the pathogenesis of isolated or syndromic pediatric cardiomyopathies is becoming apparent. Pediatric cardiomyopathies often occur in the absence of comorbidities, such as atherosclerosis, hypertension, renal dysfunction, and diabetes mellitus; as a result, they offer insights into the primary pathogenesis of myocardial dysfunction. Large international registries have characterized the epidemiology, cause, and outcomes of pediatric cardiomyopathies. Although adult and pediatric cardiomyopathies have similar morphological and clinical manifestations, their outcomes differ significantly. Within 2 years of presentation, normalization of function occurs in 20% of children with dilated cardiomyopathy, and 40% die or undergo transplantation. Infants with hypertrophic cardiomyopathy have a 2-year mortality of 30%, whereas death is rare in older children. Sudden death is rare. Molecular evidence indicates that gene expression differs between adult and pediatric cardiomyopathies, suggesting that treatment response may differ as well. Clinical trials to support evidence-based treatments and the development of disease-specific therapies for pediatric cardiomyopathies are in their infancy. This compendium summarizes current knowledge of the genetic and molecular origins, clinical course, and outcomes of the most common phenotypic presentations of pediatric cardiomyopathies and highlights key areas where additional research is required.</p>
<p><strong>CLINICAL TRIAL REGISTRATION: </strong>URL: http://www.clinicaltrials.gov. Unique identifiers: NCT02549664 and NCT01912534.</p>