Circulating inflammatory mediators and organ dysfunction after cardiovascular surgery with cardiopulmonary bypass: a prospective observational study.

INTRODUCTION: Cardiovascular surgery with cardiopulmonary bypass (CPB) has improved in past decades, but inflammatory activation in this setting is still unpredictable and is associated with several postoperative complications. Perioperative levels of macrophage migration inhibitory factor (MIF) and other inflammatory mediators could be implicated in adverse outcomes in cardiac surgery. METHODS: Serum levels of MIF, monocyte chemoattractant protein (MCP)-1, soluble CD40 ligand, IL-6 and IL-10 from 93 patients subjected to CPB were measured by enzyme-linked immunosorbent assay and compared with specific and global postoperative organ dysfunctions through multiple organ dysfunction score (MODS) and sequential organ failure assessment (SOFA). RESULTS: Most of the cytokines measured had a peak of production between 3 and 6 hours after CPB, but maximum levels of MIF occurred earlier, at the cessation of CPB. Among specific organ dysfunctions, the most frequent was hematological, occurring in 82% of the patients. Circulatory impairment was observed in 73.1% of the patients, and 51% of these needed inotropics or vasopressors within the first 24 hours after surgery. The third most frequent dysfunction was pulmonary, occurring in 48.4% of the patients. Preoperative levels of MIF showed a relevant direct correlation with the intensity of global organ dysfunction measured by SOFA (rho = 0.46, p < 0.001) and MODS (rho = 0.50, p < 0.001) on the third day after surgery. MCP-1 production was associated with postoperative thrombocytopenia, and MIF was related to the use of a high dose of vasopressors in patients with cardiovascular impairment and also to lower values of the ratio of partial arterial oxygen tension (PaO2) to fraction of inspired oxygen (FiO2) registered in the first 24 hours after CPB. CONCLUSION: Despite the multifactorial nature of specific or multiple organ dysfunctions, MIF should be explored as a predicting factor of organ dysfunction, or even as a potential therapeutic target in decreasing postoperative complications.

Macrophage migration inhibitory factor is associated with positive cultures in patients with sepsis after cardiac surgery.

This prospective consecutive observational study describes the blood levels of macrophage migration inhibitory factor (MIF), other cytokines, and markers of acute-phase response in 49 consecutive patients who developed the clinical syndrome of sepsis after cardiac surgery. Before starting antimicrobial treatment, all patients underwent microbiologic screening, and blood samples were collected. These samples subsequently were assayed for MIF, macrophage chemoattractant protein-1 (MCP-1), tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-6 and -10, procalcitonin (PCT), and C-reactive protein (CRP). Patients with positive cultures (n = 25) had a higher mortality (P = 0.046) and higher levels of MIF (P < 0.001) than those with negative cultures (n = 24). We could not detect significant difference between the groups concerning the levels of CRP, PCT, IL6, IL10, MCP-1, or TNF-alpha. MIF levels showed an area under receiver operator curve of 0.823 for the prediction of culture-proven bacterial infection, with the best cut-off value at 988.5 pg/mL. In conclusion, circulating levels of MIF could be indicated as a valuable marker of microbiologically documented sepsis in patients after cardiac surgery, which suggests that MIF may be prospectively explored as a useful diagnostic tool in this setting.

Circulating levels of macrophage migration inhibitory factor are associated with mild pulmonary dysfunction after cardiopulmonary bypass.

Macrophage migration inhibitory factor (MIF) is a central mediator of inflammatory response and acute lung injury that is secreted in response to corticosteroids. A rise in systemic MIF levels was described after cardiac surgery in steroid-treated patients. This study aimed to investigate the circulating levels of MIF and the possible relationship of this cytokine to pulmonary dysfunction after cardiopulmonary bypass (CPB). We included 74 patients without previous organ dysfunction undergoing elective coronary artery bypass surgery (CABS). The same team performed all CABS via a standard technique adding methylprednisolone (15 mg/kg) to the CPB priming solution (Group MP, n = 37). In the remaining patients (Group NS, n = 37), methylprednisolone was withdrawn from the CPB priming. MIF, C-reactive protein (CRP), and total C3 were assayed in peripheral blood sampled immediately before anesthesia induction and 3, 6, and 24 h post-CPB. Preoperative risk scores and peri- and postoperative variables were documented. Postoperative kinetics of MIF and C3 were similar for both groups. Levels of CRP 24 h post-CPB were higher in Group MP (P = 0.003). Higher MIF levels were detected 6 h post-CPB, and returned to preoperative levels 24 h after CPB. MIF levels 6 h post-CPB were inversely related to the postoperative PaO2/FiO2 ratio (P = 0.0021) and were directly related to the duration of mechanical ventilation (P = 0.014). Perioperative use of methylprednisolone did not modify the MIF response to CPB, but it was related to an enhanced acute phase response. Higher circulating MIF levels 6 h post-CPB were associated with worse postoperative pulmonary short-course outcome.