Relative vs. absolute values: Using patient and population norms for echocardiography in pediatric cardiac transplant recipients

Intrapatient consistency and relative utility of TDI as well as other echocardiographic parameters are incompletely understood in pediatric HTx recipients. We sought to evaluate the relative strength of common echocardiographic parameters used in the evaluation of pediatric HTx recipients, including TDI. We reviewed 388 echocardiograms and 73 catheterizations from 34 pediatric HTx recipients without coronary disease over an 18-month period. Data included systolic and diastolic parameters, with VCFc and mitral annular TDI velocities. We used descriptive statistics, and analyzed intrapatient variability using MSR from one-way anova. Echocardiographic data were compared with invasively measured hemodynamic data. For most echocardiographic parameters, including TDI velocities, intrapatient variability was smaller than total population variability. VCFc was higher than normal in most patients. TDI parameters were approximately 10% slower than in previously published studies of normal subjects. Pediatric HTx normal ranges are not the same as healthy population norms, and the range of findings in healthy HTx recipients without rejection is relatively broad. Serial assessment is important when interpreting echocardiograms in pediatric HTx recipients.