Impaired Cardiac Dimensions and Function in Children and Adolescents after Heart Transplantation Assessed by Cardiac Magnetic Resonance

Objectives: Cardiac growth after heart transplantation (HTx) in children has been reported to be normal in the long-term follow-up. The aim of our study was to evaluate ventricular volumes, mass and function in a cohort of pediatric HTx patients using cardiac magnetic resonance (CMR).

Methods: Seventy-five pediatric HTx patients (mean age: 14.0 ± 4.2 years, 26 females) were assessed by CMR 11.2 ± 5.4 years after HTx (time interval between HTx and CMR at least 1 year). Right (RV) and left ventricular (LV) volumes and LV mass were derived from short-axis cine images. The results were compared with a healthy reference population of 79 patients (mean age: 13.7 ± 3.7 years, 29 females, p = 0.30) from the German Competence Network for Congenital Heart Defects. LV strain measurements were performed using CMR feature tracking (FT) software (TomTec, Germany) and were compared with a group of 29 healthy controls (mean age: 13.3 ± 3.5 years, 13 females).

Results: Both LV and RV end-diastolic and -systolic volumes were significantly smaller in the HTx group compared with healthy controls while LV and RV mass-to-volume ratio were significantly higher in HTx patients. RV ejection fraction was significantly reduced in HTx patients whereas LV ejection fraction was preserved and did not differ between the two groups. LV longitudinal (LS) and radial strain (RS) as well as early diastolic strain rate (EDSR) were significantly reduced in the HTx group. LV-CS and LV-RS correlated with LV end diastolic volume (r = −0.24, p = 0.04 and r = 0.25, p = 0.03) and LV mass-to-volume ratio was inversely related to systolic and diastolic LV strain values.

Conclusion: Cardiac remodeling after HTx in children and adolescents is characterized by reduced biventricular dimensions and increased mass-to-volume ratio. Although global LV pump function is preserved, HTx patients are affected by biventricular systolic and diastolic dysfunction, which are associated with smaller LV dimensions.