The effects of the cardiopulmonary bypass on the gut microbiome and its contribution to postoperative SIRS

Cardiopulmonary bypass (CPB) made cardiac surgery possible. Despite its almost 70 years of existence and countless design improvements, it still represents one of the most invasive interventions on the human body's physiological integrity. The adverse effects of CPB present as systemic inflammatory response syndrome (SIRS), which in its most severe form with an incidence between 10% and 20% causes metabolic and immunological mayhem, accounting in many cases for uncontrollable hemodynamic, respiratory, and coagulative instability that may result in high rates of morbidity and mortality. Interestingly, the alterations of the intestinal microbiome during CPB and their role in immune regulation have not been thoroughly investigated. Our scientific efforts aim to identify compositional and metabolic shifts in the microbiome after CPB using metagenomics and metabolomics, to correlate these findings to the postoperative clinical outcomes of the patients, and to reveal a possible mechanistic link to the etiology SIRS. This could generate novel translational and therapeutic approaches for amelioration of SIRS after CPB-assisted cardiac surgery based on microbiome modulation. Furthermore, the detection of specific baseline microbiome compositions prone to SIRS susceptibility may provide a tool for risk stratification.