The C3 content in preoperative stool of patients with CPB is correlated with the degree of myocardial I/R injury. (A-B) The correlation analysis between the level of propionate in the patient's feces before surgery and the level of Ang II in the patient's plasma before surgery (T0, A), and at the time of myocardial reperfusion (T3, B). (C-F) The correlation analysis between the level of propionate in the patient's feces before surgery and the level of CK-MB, cTn-I in the patient's plasma before surgery (T0, C&D), and at the time of myocardial reperfusion (T3, E&F). The results are expressed as the mean ± SEM, n = 38. * p < .05, ** p < .01, *** p < .001 by spearman analysis.