The RIKADA-Study: Risk Stratification in Pediatric Patients with Primary Inherited Cardiomyopathies

Objectives: The outcome of primary cardiomyopathies (CMP) is heterogeneous, especially in children and adolescents. Patients may be diagnosed prenatally, present with acute heart failure or suffer from sudden cardiac death. In the RIKADA study a systematic phenotype and genotype characterization of CMP patients and first degree family members is performed. The aim is to establish parameters which allow the detection of individuals at high risk for adverse outcome.

Methods: An analysis of patients enrolled between February 2014 and May 2017 was performed. The study protocol included physical examination, ECG, echocardiography, if applicable cardiopulmonary exercise testing, cardiovascular magnetic resonance (CMR) imaging, and laboratory analyses. Follow-up examinations are planned every 3 years in patients and every 6 years in siblings until the age of 21 years.

Results: 61 patients with CMP were included (34% dilated CMP, DCM; 28% hypertrophic CMP, HCM; 25% left ventricular noncompaction CMP, LVNC; 8% restrictive CMP, RCM; 5% arrhythmogenic right ventricular CMP, ARVC). Median age (range) of index patients was 7.8 (0.06–18.1) years, 59% male. 28% had symptoms of heart failure. 25% underwent heart transplantation, 2 died. Pro brain natriuretic peptide (proBNP) was 1,465.5 (5.0–81,694.0) pg/mL (n = 54/61). Echo (n = 59/61): monoplane LV-EF 54.5 (7–77) %. CMR (n = 29/61): LV-EF 57.0 (11–88) %, LV-EDV 94.9 (50.6–253.0) mL/m². Between the CMP groups there were significant differences in proBNP values (p = 0.039), monoplane LV-EF in Echo (p < 0.001), and LV-EF (p < 0.001) and LVEDV (p = 0.012) in CMR. Comparing LVNC and DCM, the DCM group had significantly lower LV-EF (p < 0.001), increased LV-EDV (p = 0.003), but not higher proBNP levels (p = 0.114). In DCM and RCM patients NYHA classes III (n = 6/8) and IV (n = 2/2) accumulated, corresponding proBNP levels were elevated (DCM: 4,947.0 (6.9–81,694.0) pg/mL; RCM: 2,384 (951.6–13,059.0) pg/mL).

Conclusion: Within the RIKADA cohort we found significant variability of morphologic and functional parameters for specific CMP groups. Especially for DCM patients our data revealed more severe courses compared with LVNC patients supporting the concept of two independent entities. DCM and RCM patients present as high risk groups with severe clinical outcomes. The planned follow-ups will enable detailed risk stratification and may help to identify patients that benefit from early intensive heart failure treatment.

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