Preoperative Pulmonary Blood Flow, Cardiopulmonary Bypass, and Lung Inflammation in Children With Congenital Heart Disease: Post Hoc Analysis of a Single-Center Prospective Cohort

OBJECTIVE: To evaluate inflammatory biomarkers and lipidomic profiles in tracheal aspirates (TA) of infants with congenital heart disease (CHD), by pulmonary blood flow (Qp) high/low grouping at the time of cardiac surgery on cardiopulmonary bypass (CPB), and to examine associations across CHD phenotypes. DESIGN: Post hoc analysis of patient samples obtained from a single-center prospective study. SETTING: Pediatric Cardiovascular Surgery Unit, Padova, Italy. PATIENTS: Samples from 79 infants with CHD who were enrolled in a prospective study were analyzed and classified by Qp (33/79 low and 46/79 high) according to pulmonary valve size at surgery. We also studied 23 infants without cardiorespiratory disease who served as controls. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Clinical data and lung mechanics at the time of anesthesia induction, at surgery end, and every 6 hours for 24 hours were collected. TA samples collected before and after surgery were used to quantify epithelial lining fluid (ELF) total proteins (TP), surfactant protein B (SP-B), and cytokines. The lipidomic profile was generated by mass spectrometry. Before surgery, ELF TP and SP-B were increased in CHD infants compared with controls. Sphingomyelin and phosphatidylglycerol percentages were significantly increased, whereas lysophosphatidylcholines and plasmalogens were significantly decreased. In the post-surgery samples, proinflammatory cytokines increased, especially in the low Qp group. This inflammatory response was associated with reduced dynamic compliance in the first 12 hours, and with longer respiratory support and ICU stay compared with the high Qp group. In the low Qp group, cytokine increase was associated with reduced oxygen diffusion capacity, and with the degree and length of minimum temperature during CPB. CONCLUSIONS: In this post hoc analysis of TA samples from CHD infants undergoing surgery with CPB, we have shown that preoperative Qp phenotype was associated with an enhanced inflammatory response, highlighting potential opportunities for phenotype-specific strategies to improve postoperative outcome.