Echocardiography is a key diagnostic tool for medical decision-making following congenital heart surgery. Overall utilisation of echocardiography for specific congenital heart lesions following cardiac surgery has not previously been reported. This study aims to assess echocardiogram utilisation following the surgical repair of CHD to describe the variation in use across centres and provide clinical benchmarks.

All patients < 18 years of age undergoing surgical repair of CHD were identified from the Pediatric Health Information System from 2010 to 2019. Surgeries were grouped based on their Risk Adjustment for Congenital Heart Surgery-1 scores. Detailed billing data were used to assess the frequency/cost of post-operative echocardiograms, phase of hospital care, and hospital length of stay.

In total, 37,238 surgical encounters were identified for inclusion across 48 centres. Higher Risk Adjustment for Congenital Heart Surgery scores were associated with an increased median number of post-operative echocardiograms (2 versus 4 in Risk Adjustment for Congenital Heart Surgery score 1 versus 6, p < 0.001), and longer median post-operative length of stay (3 days versus 31 days in Risk Adjustment for Congenital Heart Surgery score 1 versus 6, p < 0.001). After accounting for surgical complexity, there was significant variability in echocardiogram utilisation across centres (median daily echocardiogram utilisation range 0.2/day–0.6/day, p < 0.001). There is no difference in the proportion of patients with high surgical complexity (Risk Adjustment for Congenital Heart Surgery ≥ 4) between centres with high versus low echocardiogram utilisation (p = 0.44).

Increasing surgical complexity is associated with longer post-operative length of stay and increased utilisation of echocardiography. There is wide variability in echocardiography resource utilisation across centres, even when accounting for surgical complexity.

Myocardial strain measurements are increasingly used to detect complications following heart transplantation. However, the temporal association of these changes with allograft rejection is not well defined. The aim of this study was to describe the evolution of strain measurements prior to the diagnosis of rejection in paediatric heart transplant recipients.

All paediatric heart transplant recipients (2004–2015) with at least one episode of acute rejection were identified. Longitudinal and circumferential strain measurements were assessed at the time of rejection and retrospectively on all echocardiograms until the most recent negative biopsy. Smoothing technique (LOESS) was used to visualise the changes of each variable over time and estimate the time preceding rejection at which alterations are first detectable.

A total of 58 rejection episodes were included from 37 unique patients. In the presence of rejection, there were decrements from baseline in global longitudinal strain (−18.2 versus −14.1), global circumferential strain (−24.1 versus −19.6), longitudinal strain rate (−1 versus −0.8), circumferential strain rate (−1.3 versus −1.1), peak longitudinal early diastolic strain rate (1.3 versus 1), and peak circumferential early diastolic strain rate (1.5 versus 1.3) (p<0.01 for all). The earliest detectable changes occurred 45 days prior to rejection with simultaneous alterations in myocardial strain and ejection fraction.

Changes in graft function can be detected non-invasively prior to the diagnosis of rejection. However, changes in strain occur concurrently with a decline in ejection fraction. Strain measurements aid in the non-invasive detection of rejection, but may not facilitate earlier diagnosis compared to more traditional measures of ventricular function.

Outcome analyses in large administrative databases are ideal for rare diseases such as Becker and Duchenne muscular dystrophy. Unfortunately, Becker and Duchenne do not yet have specific International Classification of Disease-9/-10 codes. We hypothesised that an algorithm could accurately identify these patients within administrative data and improve assessment of cardiovascular morbidity.

Hospital discharges (n=13,189) for patients with muscular dystrophy classified by International Classification of Disease-9 code: 359.1 were identified from the Pediatric Health Information System database. An identification algorithm was created and then validated at three institutions. Multi-variable generalised linear mixed-effects models were used to estimate the associations of length of stay, hospitalisation cost, and 14-day readmission with age, encounter severity, and respiratory disease accounting for clustering within the hospital.

The identification algorithm improved identification of patients with Becker and Duchenne from 55% (code 359.1 alone) to 77%. On bi-variate analysis, left ventricular dysfunction and arrhythmia were associated with increased cost of hospitalisation, length of stay, and mortality (p<0.001). After adjustment, Becker and Duchenne patients with left ventricular dysfunction and arrhythmia had increased length of stay with rate ratio 1.4 and 1.2 (p<0.001 and p=0.004) and increased cost of hospitalization with rate ratio 1.4 and 1.4 (both p<0.001).

Our algorithm accurately identifies patients with Becker and Duchenne and can be used for future analysis of administrative data. Our analysis demonstrates the significant effects of cardiovascular disease on length of stay and hospitalisation cost in patients with Becker and Duchenne. Better recognition of the contribution of cardiovascular disease during hospitalisation with earlier more intensive evaluation and therapy may help improve outcomes in this patient population.