Respiratory viruses and postoperative hemodynamics in patients with unrestrictive congenital cardiac communications: a prospective cohort study.

BACKGROUND: Pulmonary vascular abnormalities pose a risk for severe life-threatening hemodynamic disturbances following surgical repair of congenital cardiac communications (CCCs ). In the distal lung, small airways and vessels share a common microenvironment, where biological crosstalks take place. Because respiratory cells infected by viruses express a number of molecules with potential impact on airway and vascular remodeling, we decided to test the hypothesis that CCC patients carrying viral genomes in the airways might be at a higher risk for pulmonary (and systemic) hemodynamic disturbances postoperatively.

METHODS: Sixty patients were prospectively enrolled (age 11 [7-16] months, median with interquartile range). Preoperative pulmonary/systemic mean arterial pressure ratio (PAP/SAP) was 0.78 (0.63-0.88). The presence or absence of genetic material for respiratory viruses in nasopharyngeal and tracheal aspirates was investigated preoperatively in the absence of respiratory symptoms using real-time polymerase chain reaction (kit for detection of 19 pathogens). Post-cardiopulmonary bypass (CPB) inflammatory reaction was analyzed by measuring serum levels of 36 inflammatory proteins (immunoblotting) 4 h after its termination. Postoperative hemodynamics was assessed using continuous recording of PAP and SAP with calculation of PAP/SAP ratio.

RESULTS: Viral genomes were detected in nasopharynx and the trachea in 64% and 38% of patients, respectively. Rhinovirus was the most prevalent agent. The presence of viral genomes in the trachea was associated with an upward shift of postoperative PAP curve (p = 0.011) with a PAP/SAP of 0.44 (0.36-0.50) in patients who were positive versus 0.34 (0.30-0.45) in those who were negative (p = 0.008). The presence or absence of viral genomes in nasopharynx did not help predict postoperative hemodynamics. Postoperative PAP/SAP was positively correlated with post-CPB levels of interleukin-1 receptor antagonist (p = 0.026), macrophage migration inhibitory factor (p = 0.019) and monocyte chemoattractant protein-1 (p = 0.031), particularly in patients with virus-positive tracheal aspirates.

CONCLUSIONS: Patients with CCCs carrying respiratory viral genomes in lower airways are at a higher risk for postoperative pulmonary hypertension, thus deserving special attention and care. Preoperative exposure to respiratory viruses and post-CPB inflammatory reaction seem to play a combined role in determining the postoperative behavior of the pulmonary circulation.