Abstract Body (Do not enter title and authors here):
Introduction
Pulmonary vascular remodeling is a key determinant of outcomes in patients undergoing surgery for congenital cardiac communications (CCCs). Respiratory epithelial cells infected by viruses express cytokines and growth factors with potential impact on airway and vascular remodeling.
Hypothesis
Preoperative exposure to respiratory viruses renders CCC patients susceptible to postoperative pulmonary hypertension.
Aims
To investigate if asymptomatic patients carrying respiratory viral genomes (RVGs) in the airways are at risk for pulmonary hypertension following cardiac surgery. To analyze the role of postoperative inflammatory reaction.
Methods
The study comprised patients with unrestrictive CCCs undergoing surgery under cardiopulmonary bypass (CPB). In the absence of any signs of recent infection, RVGs were searched for in nasopharyngeal aspirates 2-3 days before surgery, and in tracheal aspirates collected in the operating room (RT-PCR, panel for 19 viruses). Serum levels of 36 inflammatory proteins were measured by chemiluminescence preoperatively and 4 hours post CPB. Pulmonary/systemic mean arterial pressure ratio (PAP/SAP) computed during the first 12 hours postoperatively (invasive assessment) was defined as the study outcome. A cutoff level was set at 0.40.
Results
Sixty patients were enrolled (age 11 [7-16] months, median with interquartile range). Preoperative PAP/SAP was 0.78 (0.63-0.88). RVGs were present in nasopharyngeal and tracheal aspirates in 64% and 38% of patients, respectively. The presence of RVGs in tracheal aspirates was associated with an upward shift of postoperative PAP/SAP curve (p=0.006). The same was not observed for positive tests in nasopharyngeal aspirates (p=0.343). Of all factors analyzed as possible predictors of postoperative PAP/SAP >0.40, only preoperative peripheral oxygen saturation and the presence of RVGs in the trachea were selected at multivariate analysis (respective OR with 95% CI, 0.40 [0.23-0.72] and 4.42 [1.17-16.78]. Heightened post-CPB levels of interleukin-1 receptor antagonist and chemokines MIF and MCP-1 were found to increase the risk of having a PAP/SAP >0.40 in RVG carriers (respective OR with 95% CI, 2.04 [1.09-3.81], 2.34 [1.15-4.74] and 2.18 [1.07-4.43].
Conclusion
The observed relation of postoperative hemodynamics to respiratory viruses and post-CPB inflammatory reaction may have pathophysiological and therapeutic implications in pulmonary hypertension associated with congenital heart disease.