The Pediatric Heart Network Normal Echocardiogram Database Study had unanticipated challenges. We sought to describe these challenges and lessons learned to improve the design of future studies.

Challenges were divided into three categories: enrolment, echocardiographic imaging, and protocol violations. Memoranda, Core Lab reports, and adjudication logs were reviewed. A centre-level questionnaire provided information regarding local processes for data collection. Descriptive statistics were used, and chi-square tests determined differences in imaging quality.

For the 19 participating centres, challenges with enrolment included variations in Institutional Review Board definitions of “retrospective” eligibility, overestimation of non-White participants, centre categorisation of Hispanic participants that differed from National Institutes of Health definitions, and exclusion of potential participants due to missing demographic data. Institutional Review Board amendments resolved many of these challenges. There was an unanticipated burden imposed on centres due to high numbers of echocardiograms that were reviewed but failed to meet submission criteria. Additionally, image transfer software malfunctions delayed Core Lab image review and feedback. Between the early and late study periods, the proportion of unacceptable echocardiograms submitted to the Core Lab decreased (14 versus 7%, p < 0.01). Most protocol violations were from eligibility violations and inadvertent protected health information disclosure (overall 2.5%). Adjudication committee reviews led to protocol changes.

Numerous challenges encountered during the Normal Echocardiogram Database Study prolonged study enrolment. The retrospective design and flaws in image transfer software were key impediments to study completion and should be considered when designing future studies collecting echocardiographic images as a primary outcome.

Despite improvements in outcomes after completion of the Fontan circulation, long-term functional state varies. We sought to identify pre- and postoperative characteristics associated with overall function.

We analyzed data from 476 survivors with the Fontan circulation enrolled in the Pediatric Heart Network Fontan Cross-sectional Study. Mean age at creation of the Fontan circulation was 3.4 plus or minus 2.1 years, with a range from 0.7 to 17.5 years, and time since completion was 8.7 plus or minus 3.4 years, the range being from 1.1 to 17.3 years. We calculated a functional score for the survivors by averaging the percentile ranks of ventricular ejection fraction, maximal consumption of oxygen, the physical summary score for the Child Health Questionnaire, and a function of brain natriuretic peptide. The mean calculated score was 49.5 plus or minus 17.3, with a range from 3 to 87. After adjustment for time since completion of the circulation, we found that a lower score, and hence worse functional state, was associated with: right ventricular morphology (p less than 0.001), higher ventricular end-diastolic pressure (p equals 0.003) and lower saturations of oxygen (p equals 0.047) prior to completion of the Fontan circulation, lower income for the caregiver (p equals 0.003), and, in subjects without a prior superior cavopulmonary anastomosis, arrhythmias after completion of the circulation (p equals 0.003). The model explained almost one-fifth (18%) of the variation in the calculated scores. The score was not associated with surgical centre, sex, age, weight, fenestration, or the period of stay in hospital after completion of the Fontan circuit. A validation model, using 71 subjects randomly excluded from initial analysis, weakly correlated (R equals 0.17, p equals 0.16) with the score calculated from the dataset.

Right ventricular morphology, higher ventricular end-diastolic pressure and lower saturations of oxygen prior to completion of the Fontan circuit, lower income for the provider of care, and arrhythmias after creation of the circuit, are all associated with a worse functional state. Unmeasured factors also influence outcomes.