Computed tomography-derived normative values and z-scores of right ventricular outflow tract structures in the pediatric population

Background Recent advances in available percutaneous device technology require accurate measurements and quantification of relationships between right ventricular outflow tract (RVOT) structures in children with and without congenital heart disease to determine device suitability. To date, no population study has described normal reference ranges of these measurements by computed tomography (CT). We aimed to establish normative values for four CT-derived measurements between RVOT structures from a heterogeneous population without heart disease and develop z-scores useful for clinical practice. Methods Patients without heart disease who underwent cardiac CT between April 2014 and February 2021 at Children’s Hospital Colorado were included. Distance between the right ventricular (RV) apex to pulmonary valve (PV), PV to pulmonary trunk bifurcation, and bifurcation to the right and left pulmonary artery were measured. Previously validated models were used to normalize the measurements and calculate Z-scores. Each measurement was plotted against BSA and Z-scores distributions were used as reference lines. Results Three-hundred sixty-four healthy patients with a mean age of 8.8 years (range 1–21), 58% male, and BSA of 1 m 2 (range 0.4–2.1) were analyzed. The Haycock formula was used to present data as predicted values for a given BSA and within equations relating each measurement to BSA. Predicted values and Z-score boundaries for all measurements are presented. Conclusion We report CT-derived normative data for four measurements between RVOT structures from a heterogenous cohort of healthy children. Knowledge of this normative data will be useful in both determining device fit and customising future devices to accommodate the diverse pediatric size range. Clinical Perspective Recent advances in advanced percutaneous technology require accurate measurements and quantification of relationships between RVOT structures to determine patient selection and device suitability. The availability of a robust range of normal reference values can provide valuable information for current device selection and future development of customized devices for the RVOT tailored to accommodate the broad size, anatomic and physiologic heterogenicity seen in the pediatric population. We report CT-derived normative data for four measurements between cardio-pulmonary structures from a heterogenous cohort of healthy children and young adults. This data may be useful in planning surgical or catheter-guided interventions in the management of children with congenital heart disease.