Correlation between high-sensitivity cardiac troponin I, lactate levels, and clinical outcomes in on-pump coronary artery bypass grafting

Background: On-pump coronary artery bypass graft (CABG) causes myocardial damage and hypoperfusion. However, it is unknown how varied timings of combining serum high-sensitivity cardiac troponin I (hs-cTnI) and lactate levels in on-pump CABG surgery would affect clinical outcomes. Objectives: This study aims to evaluate serum hs-cTnI and lactate levels and their influence on postoperative clinical outcomes in patients with on-pump CABG. Materials and methods: Eleven coronary artery disease (CAD) patients were included for on-pump CABG surgery. The biomarkers were collected at four stages of onpump CABG: before sternotomy (T0, pre-cardiopulmonary bypass (pre-CPB)), 5 minutes before aortic cross-clamp of CPB (T1, preaortic cross-clamp), after aortic cross-clamp (T2, postaortic cross-clamp), and 24 hrs post-surgery in an intensive care unit (T3, ICU at 24 hrs). Results: Correlation analysis revealed that during the study period, average hs-cTnI is positively associated with lactate levels (r=0.775, p=0.005). However, 24 hours after surgery, lactate levels return more quickly than hs-cTnI levels. The average hs-cTnI and lactate levels were positively correlated with CPB time and aortic clamp time. Regarding clinical outcomes, average hs-cTnI, and lactate levels were positively associated with a length of ICU stay (r=0.717 and 0.612, p=0.013 and 0.045, respectively). However, only the lactate levels were associated with ventilator support time (r=0.674, p=0.023). Conclusion: We demonstrated that hs-cTnI and lactate levels are important markers of myocardial injury in association with hypoperfusion during on-pump CABG, and it could be used to monitor the postoperative outcome.