Myocardial tissue expression of mRNA and preoperative neutrophil-lymphocyte ratio in children undergoing congenital heart surgery.

Background: The neutrophil-lymphocyte ratio (NLR) is an easily accessible and inexpensive biomarker that has been shown to predict morbidity and mortality in congenital cardiac surgery. However, its regulatory mechanism remains unclear. This study aims to compare and correlate the tumor necrosis factor alpha (TNF-α), interleukin (IL)-1β, IL-6, and IL-10 messenger RNAs (mRNAs) with the NLR in patients with tetralogy of Fallot (ToF) and ventricular septal defect (VSD).

Methods: A prospective translational study was conducted on 10 children with ToF and 10 with VSD, aged between 1 and 24 months. The NLR was calculated from the blood count taken 24 hours before surgery. The expression of these mRNAs was analyzed in the myocardial tissue of the right atrium prior to cardiopulmonary bypass.

Results: Patients with ToF exhibited a higher NLR [ToF 0.46 (interquartile range; IQR) 0.90; VSD 0.28 (IQR 0.17); P=0.02], longer mechanical ventilation time [ToF 24 h (IQR 93); VSD 5.5 h (IQR 8); P<0.001], increased use of vasoactive drugs [ToF 2 days (IQR 1.75); VSD 0 (IQR 1); P=0.01], and longer ICU [ToF 5.5 (IQR 1); VSD 2 (IQR 0.75); P=0.02] and hospital length of stays [ToF 18 days (IQR 17.5); VSD 8.5 days (IQR 2.5); P<0.001]. A negative correlation was found between NLR and oxygen saturation (SaO) (r=-0.44; P=0.002). In terms of mRNA expression, the ToF group showed a lower expression of IL-10 mRNA (P=0.03). A positive correlation was observed between IL-10-mRNA and SaO (r=0.40; P=0.07), and a negative correlation with NLR (r=-0.27; P=0.14).

Conclusions: Patients with ToF demonstrated a higher preoperative NLR and lower IL-10 mRNA expression by what appears to be a pro-inflammatory phenotype of cyanotic patients.