Pulmonary Artery Size as a Predictor of Early Post-operative Pediatric and Congenital Heart Transplant Outcomes

Pulmonary artery size has been studied as an outcome predictor for selected congenital heart surgeries but has not been investigated in pediatric and congenital heart transplantation. We sought to evaluate pre-operative pulmonary artery size as a predictor of post-transplant outcomes. This single center retrospective study included all patients transplanted from 2014 to 2023. Echocardiography, computed tomography angiography (CTA), and catheter angiography were used to measure pre-operative pulmonary artery size. Cross-sectional areas were calculated and indexed to calculate Nakata index and lower lobe index. Outcomes included post-transplant cardiovascular and end-organ function, length of stay, and mortality. Statistical analyses included Spearman rank correlations, chi-squared tests, and Mann-Whitney U tests. Included were 68 patients with 37 (54%) having a diagnosis of congenital heart disease. Echocardiogram (n = 68), CTA (n = 52), and catheter angiogram (n = 31) measurements were analyzed. Smaller lower lobe index was associated with longer duration of post-transplant treatment with nitric oxide (p = 0.02). In the congenital heart disease cohort, smaller Nakata index was associated with pulmonary artery reconstruction during transplant (p = 0.003). Indexed pulmonary artery size was otherwise not associated with important outcomes in the entire population or congenital heart disease cohort. While pre-operative pulmonary artery size was associated with prolonged nitric oxide use, it was generally not predictive of other early post-transplant outcomes. No imaging modality was found to have superior predictive value. Use of advanced imaging to guide surgical technique during transplant may negate the impact of smaller pulmonary artery size.