<p><strong>Background</strong> Despite excellent operative survival, correction of tetralogy of Fallot frequently is accompanied by residual lesions that may affect health beyond the incident hospitalization. Measuring resource utilization, specifically cost and length of stay, provides an integrated measure of morbidity not appreciable in traditional outcomes.</p>

<p><strong>Methods and Results</strong> We conducted a retrospective cohort study, using de-identified commercial insurance claims data, of 269 children who underwent operative correction of tetralogy of Fallot from January 2004 to September 2015 with ≥2&nbsp;years of continuous follow-up (1) to describe resource utilization for the incident hospitalization and subsequent 2&nbsp;years, (2) to determine whether prolonged length of stay (&gt;7&nbsp;days) in the incident hospitalization was associated with increased subsequent resource utilization, and (3) to explore whether there was regional variation in resource utilization with both direct comparisons and multivariable models adjusting for known covariates. Subjects with prolonged incident hospitalization length of stay demonstrated greater resource utilization (total cost as well as counts of outpatient visits, hospitalizations, and catheterizations) after hospital discharge (&lt;0.0001 for each), though the number of subsequent operative and transcatheter interventions were not significantly different. Regional differences were observed in the cost of incident hospitalization as well as subsequent hospitalizations, outpatient visits, and the costs associated with each.</p>

<p><strong>Conclusions</strong> This study is the first to report short- and medium-term resource utilization following tetralogy of Fallot operative correction. It also demonstrates that prolonged length of stay in the initial hospitalization is associated with increased subsequent resource utilization. This should motivate research to determine whether these differences are because of modifiable factors.</p>