Impact of High-Sensitivity Cardiac Troponin I Elevation after On- and Off-pump Coronary Artery Bypass Grafting on Long-term Prognosis.

Background: Postoperative myocardial injury is correlated with long-term prognosis after coronary artery bypass grafting (CABG) and is diagnosed with troponin levels, which vary substantially upon surgical strategies. We aimed to explore the troponin I cut-off values for prognostically significant myocardial injury separately in on-pump and off-pump procedures with a high-sensitivity assay (hs-cTnI).

Methods: Patients who underwent isolated CABG from 2018 to 2020 with available perioperative hs-cTnI measurements were included in the current study and followed up. We explored the relationships between hs-cTnI levels and different outcomes. To identify hs-cTnI threshold levels indicative of higher risks, restrictive spline regressions were performed for on-pump and off-pump procedures.

Results: A total of 7813 patients were included with a median follow-up of 2.7 years (interquartile range [IQR]: 1.7-3.3 years) years, 218 (2.8%) of whom experienced death. Upon adjusting for clinical variables, the study found a significant association between peak hs-cTnI levels within the first 48 hours after surgery and all endpoints. The spline regressions demonstrated that the hs-cTnI levels measured within 48 hours after surgery, which were associated with a hazard ratio of more than 1.00 for all-cause death, were 1,446ng/L (55.6×upper reference limit [URL], 95% CI: 45.0-106.5) for on-pump and 564ng/L (21.7×URL, 95% CI: 21.0-30.2) for off-pump.

Conclusions: Elevated hs-cTnI levels after CABG were associated with poorer longer-term outcomes. A prognosis relevant hs-cTnI cut-off value within 48 hours post-CABG for on-pump is significantly higher than that for off-pump.