In our study, the absorbance value of the PMI-1 phage clone was found significantly correlated with the peak serum cTnI level after CABG. This suggests that PMI-1 could also be used to predict the severity of PMI after CABG, which will be examined in our future study with a larger patient sample. Since the PMI-1 mimic peptide showed no significant homology with other protein sequences, it is likely derived from an unknown protein. Exploration into the identity K6PC-5 and functional roles of PMI-1 and its parent protein may provide new insights into the molecular mechanisms underlying PMI pathogenesis. In comparison to PMI-1, the PMI-2 mimic peptide showed low predictive validity in the validation phase, which was likely due to low-specificity binding between phages and sera IgG from the PMI group in the discovery/screening phase. This was in line with the screening data that in 20 randomly picked phage clones, only 4 clones with relatively low absorbance values expressed PMI-2, while 11 clones with relatively high absorbance values expressed PMI-1. Additionally, this was also supported by our findings that the absorbance value of the PMI-1, DCAI but not the PMI-2 phage clone showed statistically significant correlation with the peak postoperative serum cTnI level. There are some limitations to this study: We only enrolled patients undergoing CABG with CPB, for this was the predominant type of patients we could have for an adequate sample size. It will be interesting to find out the predictive validity of PMI-1 in patients undergoing off-pump CABG and other cardiac surgeries. Only Chinese Han patients were enrolled in this study, which minimized background noise for the screening tests. Although Chinese Han accounts for 90% of the population in China and 19% of global population, enrollment of a single ethnicity in this study may limit the generalizability of our findings. Thus, it will be interesting to test the predictive validity of PMI-1 or screen for its counterparts in other ethnicities in future studies. In conclusion, we identified a mimic peptide PMI-1 with high validity in preoperative prediction of PMI after CABG.