Delta chemokine (fractalkine) - A novel mediator of pulmonary arterial hypertension in children undergoing cardiac surgery

Background: Fractalkine (FKN), a unique chemokine associated with pulmonary hypertension, may be involved in the acute stress response that regulates inflammation after cardiopulmonary bypass (CPB) surgery. We characterized FKN levels and correlated them with clinical parameters in children undergoing cardiac surgery involving CPB. Methods: Twenty-seven consecutive patients, aged 30. days to 11.5. years, who underwent surgery for correction of congenital heart defects, were prospectively studied. Serial blood samples were collected preoperatively, upon termination of CPB, and at six points postoperatively. Plasma was recovered immediately, aliquoted, and frozen at -70 °C until assayed. Clinical and laboratory data were collected. Results: Baseline FKN levels were skewed between patients. Patients with low FKN levels showed significantly higher levels of oxygen saturation in room air compared to patients with high FKN levels (p< 0.05). Moreover, there was a positive correlation between preoperative pulmonary arterial hypertension and FKN levels (p< 0.05). Surprisingly, FKN elevation from preoperative to postoperative levels displayed no discernible pattern. Conclusions: FKN levels significantly correlate with preoperative hypoxemia and PAH, suggesting that FKN may be up-regulated during hypoxemia. CPB is not associated with acute changes in circulating FKN levels. The role of FKN in the postoperative course should be further investigated.